blocks|key|543204|text|一种方法是修改数据源以在行数为零时返回1，并在tableView:cellForRowAtIndexPath:方法中生成一个特殊用途的单元(可能具有不同的单元标识符)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|543205|-(NSInteger)tableView:(UITableView+*)tableView+numberOfRowsInSection:(NSInteger)section+{
++++NSInteger+actualNumberOfRows+=+<calculate+the+actual+number+of+rows>;
++++return+(actualNumberOfRows++==+0)+?+1+:+actualNumberOfRows;
}

-(UITableViewCell+*)tableView:(UITableView+*)tableView+cellForRowAtIndexPath:(NSIndexPath+*)indexPath+{
++++NSInteger+actualNumberOfRows+=+<calculate+the+actual+number+of+rows>;
++++if+(actualNumberOfRows+==+0)+{
++++++++//+Produce+a+special+cell+with+the+"list+is+now+empty"+message
++++}
++++//+Produce+the+correct+cell+the+usual+way
++++...
}|code-block|syntax|javascript|543206|如果您需要维护多个表视图控制器，这可能会变得有些复杂，因为最终会有人忘记插入零检查。更好的方法是创建一个UITableViewDataSource实现的单独实现，该实现总是返回带有可配置消息的单个行(让我们称之为EmptyTableViewDataSource)。当表视图控制器管理的数据发生更改时，管理更改的代码将检查数据是否为空。如果表视图控制器不是空的，则使用其常规数据源设置表视图控制器；否则，使用配置有适当消息的EmptyTableViewDataSource实例来设置它。|543207|entityMap^0|J|1|N|W|0|0|1G|L|2Y|O|5V|O|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

One way of doing it would be modifying your data source to return <code>1</code> when the number of rows is zero, and to produce a special-purpose cell (perhaps with a different cell identifier) in the <code>tableView:cellForRowAtIndexPath:</code> method.

<pre><code>-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
 NSInteger actualNumberOfRows = &lt;calculate the actual number of rows&gt;;
 return (actualNumberOfRows == 0) ? 1 : actualNumberOfRows;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 NSInteger actualNumberOfRows = &lt;calculate the actual number of rows&gt;;
 if (actualNumberOfRows == 0) {
 // Produce a special cell with the "list is now empty" message
 }
 // Produce the correct cell the usual way
 ...
}
</code></pre>

This may get somewhat complicated if you have multiple table view controllers that you need to maintain, because someone will eventually forget to insert a zero check. A better approach is to create a separate implementation of a <code>UITableViewDataSource</code> implementation that always returns a single row with a configurable message (let's call it <code>EmptyTableViewDataSource</code>). When the data that is managed by your table view controller changes, the code that manages the change would check if the data is empty. If it is not empty, set your table view controller with its regular data source; otherwise, set it with an instance of the <code>EmptyTableViewDataSource</code> that has been configured with the appropriate message.

blocks|key|543225|text|UITableView的backgroundView属性是您的朋友。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|543226|在viewDidLoad或reloadData的任何地方，您应该确定表是否为空，并使用包含UILabel的UIView更新UITableView的backgroundView属性，或者将其设置为零。就这样。|offset|length|style|CODE|543227|当然，可以让UITableView的数据源执行双重任务，并返回一个特殊的“列表是空的”单元格，我觉得这是一个假象。突然，numberOfRowsInSection:(NSInteger)section不得不计算其他部分的行数--它没有被要求确保它们也是空的。您还需要创建一个包含空消息的特殊单元格。另外，不要忘记，您可能需要更改单元格的高度以容纳空消息。这一切都是可行的，但看起来就像绷带上的绷带。|543228|entityMap^0|0|1|B|D|A|0|1O|14|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]|$D|P|E|Q|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|K|$]]

UITableView's backgroundView property is your friend.

In <code>viewDidLoad</code> or anywhere that you <code>reloadData</code> you should determine if there your table is empty or not and update the UITableView's backgroundView property with a UIView containing a UILabel or just set it to nil. That's it.

It is of course possible to make UITableView's data source do double duty and return a special "list is empty" cell, it strikes me as a kludge. Suddenly <code>numberOfRowsInSection:(NSInteger)section</code> has to compute the number of rows of other sections it wasn't asked about to make sure they are empty too. You also need to make a special cell that has the empty message. Also don't forget that you need to probably change the height of your cell to accommodate the empty message. This is all doable but it seems like band-aid on top of band-aid.

blocks|key|2653795|text|首先，其他流行方法的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2653796|BackgroundView|offset|length|style|BOLD|2653797|如果要使用设置为UILabel的简单示例，背景视图就不会很好地居中。|2653798|单元格、标头或页脚以显示消息|2653799|这会干扰您的功能代码，并引入奇怪的边缘情况。如果您想要完美地集中您的信息，这就增加了另一个层次的复杂性。|2653800|滚动您自己的表视图控制器|2653801|您将失去内置功能，如refreshControl，并重新发明车轮。坚持UITableViewController以获得最佳可维护的结果。|2653802|将UITableViewController添加为子视图控制器|2653803|我有种预感，你最终会在contentInset+7%2B中出现问题--还有为什么事情会变得复杂呢？|2653804|我的解决方案|2653805|我想出的最好的解决方案(当然，这并不理想)是创建一个特殊的视图，可以放在滚动视图的顶部，并相应地采取相应的行动。这显然在iOS+7中变得复杂了，contentInset疯狂，但它是可行的。|2653806|你必须小心的事情：|2653807|在reloadData的某个时刻，表分隔符会被带到前面--您需要防范这种情况。|unordered-list-item|2653808|contentInset/contentOffset+-在您的特殊视图中观察这些键|2653809|键盘--如果你不想让键盘挡道，那是另一种计算|2653810|自动收费表-您不能依靠帧更改来定位您的视图|2653811|一旦您在一个UIView子类中找到了这个问题，您就可以将它用于所有方面--加载旋转器、禁用视图、显示错误消息等等。|2653812|entityMap^0|0|0|E|0|0|0|E|0|0|0|C|0|0|0|V|0|0|0|6|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1F|8|@$D|1G|E|1H|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|1I|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1J|8|@$D|1K|E|1L|F|G]]|9|@]|A|$]]|$1|L|3|M|5|6|7|1M|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1N|8|@$D|1O|E|1P|F|G]]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|1R|8|@$D|1S|E|1T|F|G]]|9|@]|A|$]]|$1|T|3|U|5|6|7|1U|8|@]|9|@]|A|$]]|$1|V|3|W|5|6|7|1V|8|@$D|1W|E|1X|F|G]]|9|@]|A|$]]|$1|X|3|Y|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|11|3|12|5|13|7|20|8|@]|9|@]|A|$]]|$1|14|3|15|5|13|7|21|8|@]|9|@]|A|$]]|$1|16|3|17|5|13|7|22|8|@]|9|@]|A|$]]|$1|18|3|19|5|13|7|23|8|@]|9|@]|A|$]]|$1|1A|3|1B|5|6|7|24|8|@]|9|@]|A|$]]|$1|1C|3|-4|5|6|7|25|8|@]|9|@]|A|$]]]|1D|$]]

First, the problems with other popular approaches.

BackgroundView

Background view doesn't center nicely if you were to use the simple case of setting it to be a UILabel.

Cells, headers, or footers to display the message

This interferes with your functional code and introduces weird edge cases. If you want to perfectly center your message, that adds another level of complexity.

Rolling your own table view controller

You lose built-in functionality, such as refreshControl, and re-invent the wheel. Stick to UITableViewController for the best maintainable results.

Adding UITableViewController as a child view controller

I have a feeling you'll end up with contentInset issues in iOS 7+ - plus why complicate things?

My solution

The best solution I've come up with (and, granted, this isn't ideal) is to make a special view that can sit on top of a scroll view and act accordingly. This obviously gets complicated in iOS 7 with contentInset madness, but it's doable.

Things you have to watch out for:

<ul>
<li>table separators get brought to front at some point during reloadData - you need to guard against that</li>
<li>contentInset/contentOffset - observe those keys on your special view</li>
<li>keyboard - if you don't want the keyboard to get in the way, that's another calculation</li>
<li>autolayout - you can't depend on frame changes to position your view</li>
</ul>

Once you have this figured out once in one UIView subclass, you can use it for everything - loading spinners, disabling views, showing error messages, etc.

blocks|key|2653833|text|为此，我一直在使用titleForFooterInSection消息。我不知道这是不是次优，但它有效。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2653834|-(NSString*)tableView:(UITableView+*)tableView+titleForFooterInSection:(NSInteger)section+++{

++++NSString+*message+=+@"";
++++NSInteger+numberOfRowsInSection+=+[self+tableView:self.tableView+numberOfRowsInSection:section+];

++++if+(numberOfRowsInSection+==+0)+{
++++++++message+=+@"This+list+is+now+empty";
++++}

++++return+message;
}|code-block|syntax|javascript|2653835|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I have been using the titleForFooterInSection message for this. I don't know if this is suboptimal or not, but it works. 

<pre><code>-(NSString*)tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section {

 NSString *message = @"";
 NSInteger numberOfRowsInSection = [self tableView:self.tableView numberOfRowsInSection:section ];

 if (numberOfRowsInSection == 0) {
 message = @"This list is now empty";
 }

 return message;
}
</code></pre>

blocks|key|2653850|text|我只能建议在单元格之后将一个UITextView拖放到TableView中。建立到ViewController的连接，并在适当时隐藏/显示它(例如，每当表重新加载时)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2653851|​|2653852|📷|atomic|offset|length|2653853|2653854|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/ef4172b6c1e164d07ceffbf3499152f5.png|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@$G|V|H|W|1|X]]|A|$]]|$1|I|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q|R|-4]]]]

I can only recommend to drag&amp;drop a UITextView inside the TableView after the cells. Make a connection to the ViewController and hide/display it when appropriate (e.g. whenever the table reloads).

<a href="https://i.stack.imgur.com/YCA2Q.png" rel="noreferrer"><img src="https://i.stack.imgur.com/YCA2Q.png" alt="enter image description here"></a>

blocks|key|543347|text|根据这里的答案，这是我做的一个快速类，您可以在UITableViewController中使用它。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|543348|import+Foundation
import+UIKit

class+TableViewHelper+{

++++class+func+EmptyMessage(message:String,+viewController:UITableViewController)+{
++++++++let+rect+=+CGRect(origin:+CGPoint(x:+0,y+:0),+size:+CGSize(width:+self.view.bounds.size.width,+height:+self.view.bounds.size.height))
++++++++let+messageLabel+=+UILabel(frame:+rect)
++++++++messageLabel.text+=+message
++++++++messageLabel.textColor+=+UIColor.blackColor()
++++++++messageLabel.numberOfLines+=+0;
++++++++messageLabel.textAlignment+=+.Center;
++++++++messageLabel.font+=+UIFont(name:+"TrebuchetMS",+size:+15)
++++++++messageLabel.sizeToFit()

++++++++viewController.tableView.backgroundView+=+messageLabel;
++++++++viewController.tableView.separatorStyle+=+.None;
++++}
}|code-block|syntax|javascript|543349|在您的UITableViewController中，您可以在numberOfSectionsInTableView(tableView:+UITableView)+->+Int中调用它|543350|override+func+numberOfSectionsInTableView(tableView:+UITableView)+->+Int+{
++++if+projects.count+>+0+{
++++++++return+1
++++}+else+{
++++++++TableViewHelper.EmptyMessage("You+don't+have+any+projects+yet.\nYou+can+create+up+to+10.",+viewController:+self)
++++++++return+0
++++}
}|543351|​|543352|📷|atomic|543353|543354|在http://www.appcoda.com/pull-to-refresh-uitableview-empty/的帮助下|543355|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/57e71b7d4a82666141c869c08cabebae.png|imageAlt|1|LINK|MUTABLE|url|http://www.appcoda.com/pull-to-refresh-uitableview-empty/^0|N|L|0|0|3|L|U|1M|0|0|0|0|1|0|0|0|1|1L|1|0^^$0|@$1|2|3|4|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Q|3|R|5|S|7|1L|8|@]|D|@$9|1M|A|1N|1|1O]]|E|$]]|$1|T|3|P|5|6|7|1P|8|@]|D|@]|E|$]]|$1|U|3|V|5|6|7|1Q|8|@]|D|@$9|1R|A|1S|1|1T]]|E|$]]|$1|W|3|-4|5|6|7|1U|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13|14|-4]]|15|$5|16|10|17|E|$18|19]]]]

Based on the answers here, here is a quick class I made that you can use on in your <code>UITableViewController</code>.

<pre><code>import Foundation
import UIKit

class TableViewHelper {

 class func EmptyMessage(message:String, viewController:UITableViewController) {
 let rect = CGRect(origin: CGPoint(x: 0,y :0), size: CGSize(width: self.view.bounds.size.width, height: self.view.bounds.size.height))
 let messageLabel = UILabel(frame: rect)
 messageLabel.text = message
 messageLabel.textColor = UIColor.blackColor()
 messageLabel.numberOfLines = 0;
 messageLabel.textAlignment = .Center;
 messageLabel.font = UIFont(name: "TrebuchetMS", size: 15)
 messageLabel.sizeToFit()

 viewController.tableView.backgroundView = messageLabel;
 viewController.tableView.separatorStyle = .None;
 }
}
</code></pre>

In your <code>UITableViewController</code> you can call this in <code>numberOfSectionsInTableView(tableView: UITableView) -&gt; Int</code>

<pre><code>override func numberOfSectionsInTableView(tableView: UITableView) -&gt; Int {
 if projects.count &gt; 0 {
 return 1
 } else {
 TableViewHelper.EmptyMessage("You don't have any projects yet.\nYou can create up to 10.", viewController: self)
 return 0
 }
}
</code></pre>

<a href="https://i.stack.imgur.com/wpbHj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/wpbHj.png" alt="enter image description here"></a>

With a little help from <a href="http://www.appcoda.com/pull-to-refresh-uitableview-empty/" rel="noreferrer">http://www.appcoda.com/pull-to-refresh-uitableview-empty/</a>

blocks|key|1864190|text|我推荐以下库：DZNEmptyDataSet|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1864191|在项目中添加它的最简单方法是将它与Cocaopods一起使用，如：pod+'DZNEmptyDataSet'|style|CODE|1864192|在TableViewController中添加以下导入语句(Swift)：|1864193|import+DZNEmptyDataSet|code-block|syntax|javascript|1864194|然后确保类符合DNZEmptyDataSetSource和DZNEmptyDataSetDelegate，如下所示：|1864195|class+MyTableViewController:+UITableViewController,+DZNEmptyDataSetSource,+DZNEmptyDataSetDelegate|1864196|在viewDidLoad中添加以下代码行：|1864197|tableView.emptyDataSetSource+=+self
tableView.emptyDataSetDelegate+=+self
tableView.tableFooterView+=+UIView()|1864198|现在，要显示空状态，所要做的就是：|1864199|//Add+title+for+empty+dataset
func+titleForEmptyDataSet(scrollView:+UIScrollView!)+->+NSAttributedString!+{
++++let+str+=+"Welcome"
++++let+attrs+=+[NSFontAttributeName:+UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//Add+description/subtitle+on+empty+dataset
func+descriptionForEmptyDataSet(scrollView:+UIScrollView!)+->+NSAttributedString!+{
++++let+str+=+"Tap+the+button+below+to+add+your+first+grokkleglob."
++++let+attrs+=+[NSFontAttributeName:+UIFont.preferredFontForTextStyle(UIFontTextStyleBody)]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//Add+your+image
func+imageForEmptyDataSet(scrollView:+UIScrollView!)+->+UIImage!+{
++++return+UIImage(named:+"MYIMAGE")
}

//Add+your+button+
func+buttonTitleForEmptyDataSet(scrollView:+UIScrollView!,+forState+state:+UIControlState)+->+NSAttributedString!+{
++++let+str+=+"Add+Grokkleglob"
++++let+attrs+=+[NSFontAttributeName:+UIFont.preferredFontForTextStyle(UIFontTextStyleCallout)]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//Add+action+for+button
func+emptyDataSetDidTapButton(scrollView:+UIScrollView!)+{
++++let+ac+=+UIAlertController(title:+"Button+tapped!",+message:+nil,+preferredStyle:+.Alert)
++++ac.addAction(UIAlertAction(title:+"Hurray",+style:+.Default,+handler:+nil))
++++presentViewController(ac,+animated:+true,+completion:+nil)
}|1864200|这些方法不是强制性的，也可以只显示没有按钮的空状态等等。|1864201|Swift+4+4|BOLD|1864202|//+MARK:+-+Deal+with+the+empty+data+set
//+Add+title+for+empty+dataset
func+title(forEmptyDataSet+_:+UIScrollView!)+->+NSAttributedString!+{
++++let+str+=+"Welcome"
++++let+attrs+=+[NSAttributedStringKey.font:+UIFont.preferredFont(forTextStyle:+UIFontTextStyle.headline)]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//+Add+description/subtitle+on+empty+dataset
func+description(forEmptyDataSet+_:+UIScrollView!)+->+NSAttributedString!+{
++++let+str+=+"Tap+the+button+below+to+add+your+first+grokkleglob."
++++let+attrs+=+[NSAttributedStringKey.font:+UIFont.preferredFont(forTextStyle:+UIFontTextStyle.body)]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//+Add+your+image
func+image(forEmptyDataSet+_:+UIScrollView!)+->+UIImage!+{
++++return+UIImage(named:+"MYIMAGE")
}

//+Add+your+button
func+buttonTitle(forEmptyDataSet+_:+UIScrollView!,+for+_:+UIControlState)+->+NSAttributedString!+{
++++let+str+=+"Add+Grokkleglob"
++++let+attrs+=+[NSAttributedStringKey.font:+UIFont.preferredFont(forTextStyle:+UIFontTextStyle.callout),+NSAttributedStringKey.foregroundColor:+UIColor.white]
++++return+NSAttributedString(string:+str,+attributes:+attrs)
}

//+Add+action+for+button
func+emptyDataSetDidTapButton(_:+UIScrollView!)+{
++++let+ac+=+UIAlertController(title:+"Button+tapped!",+message:+nil,+preferredStyle:+.alert)
++++ac.addAction(UIAlertAction(title:+"Hurray",+style:+.default,+handler:+nil))
++++present(ac,+animated:+true,+completion:+nil)
}|1864203|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/dzenbot/DZNEmptyDataSet^0|7|F|0|0|X|L|0|0|0|7|L|T|N|0|0|1|B|0|0|0|0|0|7|2|0|0^^$0|@$1|2|3|4|5|6|7|1F|8|@]|9|@$A|1G|B|1H|1|1I]]|C|$]]|$1|D|3|E|5|6|7|1J|8|@$A|1K|B|1L|F|G]]|9|@]|C|$]]|$1|H|3|I|5|6|7|1M|8|@]|9|@]|C|$]]|$1|J|3|K|5|L|7|1N|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|1O|8|@$A|1P|B|1Q|F|G]|$A|1R|B|1S|F|G]]|9|@]|C|$]]|$1|Q|3|R|5|L|7|1T|8|@]|9|@]|C|$M|N]]|$1|S|3|T|5|6|7|1U|8|@$A|1V|B|1W|F|G]]|9|@]|C|$]]|$1|U|3|V|5|L|7|1X|8|@]|9|@]|C|$M|N]]|$1|W|3|X|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|L|7|1Z|8|@]|9|@]|C|$M|N]]|$1|10|3|11|5|6|7|20|8|@]|9|@]|C|$]]|$1|12|3|13|5|6|7|21|8|@$A|22|B|23|F|14]]|9|@]|C|$]]|$1|15|3|16|5|L|7|24|8|@]|9|@]|C|$M|N]]|$1|17|3|-4|5|6|7|25|8|@]|9|@]|C|$]]]|18|$19|$5|1A|1B|1C|C|$1D|1E]]]]

I recommend the following library: <a href="https://github.com/dzenbot/DZNEmptyDataSet" rel="noreferrer">DZNEmptyDataSet</a>

The easiest way to add it in your project is to use it with Cocaopods like so: <code>pod 'DZNEmptyDataSet'</code>

In your TableViewController add the following import statement (Swift): 

<pre><code>import DZNEmptyDataSet
</code></pre>

Then make sure your class conforms to the <code>DNZEmptyDataSetSource</code> and <code>DZNEmptyDataSetDelegate</code> like so:

<pre><code>class MyTableViewController: UITableViewController, DZNEmptyDataSetSource, DZNEmptyDataSetDelegate
</code></pre>

In your <code>viewDidLoad</code> add the following lines of code:

<pre><code>tableView.emptyDataSetSource = self
tableView.emptyDataSetDelegate = self
tableView.tableFooterView = UIView()
</code></pre>

Now all you have to do to show the emptystate is: 

<pre><code>//Add title for empty dataset
func titleForEmptyDataSet(scrollView: UIScrollView!) -&gt; NSAttributedString! {
 let str = "Welcome"
 let attrs = [NSFontAttributeName: UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)]
 return NSAttributedString(string: str, attributes: attrs)
}

//Add description/subtitle on empty dataset
func descriptionForEmptyDataSet(scrollView: UIScrollView!) -&gt; NSAttributedString! {
 let str = "Tap the button below to add your first grokkleglob."
 let attrs = [NSFontAttributeName: UIFont.preferredFontForTextStyle(UIFontTextStyleBody)]
 return NSAttributedString(string: str, attributes: attrs)
}

//Add your image
func imageForEmptyDataSet(scrollView: UIScrollView!) -&gt; UIImage! {
 return UIImage(named: "MYIMAGE")
}

//Add your button 
func buttonTitleForEmptyDataSet(scrollView: UIScrollView!, forState state: UIControlState) -&gt; NSAttributedString! {
 let str = "Add Grokkleglob"
 let attrs = [NSFontAttributeName: UIFont.preferredFontForTextStyle(UIFontTextStyleCallout)]
 return NSAttributedString(string: str, attributes: attrs)
}

//Add action for button
func emptyDataSetDidTapButton(scrollView: UIScrollView!) {
 let ac = UIAlertController(title: "Button tapped!", message: nil, preferredStyle: .Alert)
 ac.addAction(UIAlertAction(title: "Hurray", style: .Default, handler: nil))
 presentViewController(ac, animated: true, completion: nil)
}
</code></pre>

These methods aren't mandatory, it's also possible to just show the empty state without a button etc.

For Swift 4

<pre><code>// MARK: - Deal with the empty data set
// Add title for empty dataset
func title(forEmptyDataSet _: UIScrollView!) -&gt; NSAttributedString! {
 let str = "Welcome"
 let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)]
 return NSAttributedString(string: str, attributes: attrs)
}

// Add description/subtitle on empty dataset
func description(forEmptyDataSet _: UIScrollView!) -&gt; NSAttributedString! {
 let str = "Tap the button below to add your first grokkleglob."
 let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body)]
 return NSAttributedString(string: str, attributes: attrs)
}

// Add your image
func image(forEmptyDataSet _: UIScrollView!) -&gt; UIImage! {
 return UIImage(named: "MYIMAGE")
}

// Add your button
func buttonTitle(forEmptyDataSet _: UIScrollView!, for _: UIControlState) -&gt; NSAttributedString! {
 let str = "Add Grokkleglob"
 let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.callout), NSAttributedStringKey.foregroundColor: UIColor.white]
 return NSAttributedString(string: str, attributes: attrs)
}

// Add action for button
func emptyDataSetDidTapButton(_: UIScrollView!) {
 let ac = UIAlertController(title: "Button tapped!", message: nil, preferredStyle: .alert)
 ac.addAction(UIAlertAction(title: "Hurray", style: .default, handler: nil))
 present(ac, animated: true, completion: nil)
}
</code></pre>

blocks|key|1864260|text|使用backgroundView很好，但它不像在Mail.app中那样滚动得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1864261|我做了一些类似于xtravar所做的事情。|offset|length|1864262|我在tableViewController的视图层次结构之外添加了一个视图。|style|CODE|1864263|📷|atomic|1864264|​|1864265|然后我在tableView:numberOfRowsInSection:中使用了以下代码|1864266|if+someArray.count+==+0+{
++++//+Show+Empty+State+View
++++self.tableView.addSubview(self.emptyStateView)
++++self.emptyStateView.center+=+self.view.center
++++self.emptyStateView.center.y+-=+60+//+rough+calculation+here
++++self.tableView.separatorColor+=+UIColor.clear
}+else+if+self.emptyStateView.superview+!=+nil+{
++++//+Empty+State+View+is+currently+visible,+but+shouldn't
++++self.emptyStateView.removeFromSuperview()
++++self.tableView.separatorColor+=+nil
}

return+someArray.count|code-block|syntax|javascript|1864267|基本上，我添加了emptyStateView作为tableView对象的子视图。由于分隔符将与视图重叠，我将其颜色设置为clearColor。要回到默认的分隔符颜色，只需将其设置为nil即可。|1864268|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/22444746/4113940|1|IMAGE|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/6ed535b84391f4fc78a4e6d09e62f302.png|imageAlt^0|0|8|7|0|0|2|J|0|0|1|1|0|0|4|W|0|0|8|E|O|9|1O|A|2I|3|0^^$0|@$1|2|3|4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1C|8|@]|9|@$D|1D|E|1E|1|1F]]|A|$]]|$1|F|3|G|5|6|7|1G|8|@$D|1H|E|1I|H|I]]|9|@]|A|$]]|$1|J|3|K|5|L|7|1J|8|@]|9|@$D|1K|E|1L|1|1M]]|A|$]]|$1|M|3|N|5|6|7|1N|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1O|8|@$D|1P|E|1Q|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|S|7|1R|8|@]|9|@]|A|$T|U]]|$1|V|3|W|5|6|7|1S|8|@$D|1T|E|1U|H|I]|$D|1V|E|1W|H|I]|$D|1X|E|1Y|H|I]|$D|1Z|E|20|H|I]]|9|@]|A|$]]|$1|X|3|-4|5|6|7|21|8|@]|9|@]|A|$]]]|Y|$Z|$5|10|11|12|A|$13|14]]|15|$5|16|11|17|A|$18|19|1A|-4]]]]

Using the backgroundView is fine, but it does not scroll nicely like in Mail.app.

I did something similar to what <a href="https://stackoverflow.com/a/22444746/4113940">xtravar</a> did. 

I added a view outside the view hierarchy of the <code>tableViewController</code>.
<a href="https://i.stack.imgur.com/o2myj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/o2myj.png" alt="hierarchy"></a>

Then i used the following code in <code>tableView:numberOfRowsInSection:</code>:

<pre><code>if someArray.count == 0 {
 // Show Empty State View
 self.tableView.addSubview(self.emptyStateView)
 self.emptyStateView.center = self.view.center
 self.emptyStateView.center.y -= 60 // rough calculation here
 self.tableView.separatorColor = UIColor.clear
} else if self.emptyStateView.superview != nil {
 // Empty State View is currently visible, but shouldn't
 self.emptyStateView.removeFromSuperview()
 self.tableView.separatorColor = nil
}

return someArray.count
</code></pre>

Basically I added the <code>emptyStateView</code> as a subview of the <code>tableView</code> object. As the separators would overlap the view, I set their color to <code>clearColor</code>.
To get back to the default separator color, you can just set it to <code>nil</code>.

blocks|key|2654125|text|快速版本，但更好和更简单的形式。**3.0|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2654126|我希望这能达到你的目的.|2654127|在你的UITableViewController里。|2654128|override+func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{
++++if+searchController.isActive+&&+searchController.searchBar.text+!=+""+{
++++++++if+filteredContacts.count+>+0+{
++++++++++++self.tableView.backgroundView+=+.none;
++++++++++++return+filteredContacts.count
++++++++}+else+{
++++++++++++Helper.EmptyMessage(message:+ConstantMap.NO_CONTACT_FOUND,+viewController:+self)
++++++++++++return+0
++++++++}
++++}+else+{
++++++++if+contacts.count+>+0+{
++++++++++++self.tableView.backgroundView+=+.none;
++++++++++++return+contacts.count
++++++++}+else+{
++++++++++++Helper.EmptyMessage(message:+ConstantMap.NO_CONTACT_FOUND,+viewController:+self)
++++++++++++return+0
++++++++}
++++}
}|code-block|syntax|javascript|2654129|具有函数的帮助类:|2654130|+/*+Description:+This+function+generate+alert+dialog+for+empty+message+by+passing+message+and
+++++++++++associated+viewcontroller+for+that+function
+++++++++++-+Parameters:
++++++++++++-+message:+message+that+require+for++empty+alert+message
++++++++++++-+viewController:+selected+viewcontroller+at+that+time
+++++++++*/
++++++++static+func+EmptyMessage(message:String,+viewController:UITableViewController)+{
++++++++++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+viewController.view.bounds.size.width,+height:+viewController.view.bounds.size.height))
++++++++++++messageLabel.text+=+message
++++++++++++let+bubbleColor+=+UIColor(red:+CGFloat(57)/255,+green:+CGFloat(81)/255,+blue:+CGFloat(104)/255,+alpha+:1)

++++++++++++messageLabel.textColor+=+bubbleColor
++++++++++++messageLabel.numberOfLines+=+0;
++++++++++++messageLabel.textAlignment+=+.center;
++++++++++++messageLabel.font+=+UIFont(name:+"TrebuchetMS",+size:+18)
++++++++++++messageLabel.sizeToFit()

++++++++++++viewController.tableView.backgroundView+=+messageLabel;
++++++++++++viewController.tableView.separatorStyle+=+.none;
++++++++}|2654131|entityMap^0|0|L|0|0|0|0|5|4|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|Z|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|L|7|13|8|@]|D|@]|E|$M|N]]|$1|S|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|T|$]]

Swift version but better and simpler form . **3.0

I hope it server your purpose......

In your UITableViewController .

<pre><code>override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
 if searchController.isActive &amp;&amp; searchController.searchBar.text != "" {
 if filteredContacts.count &gt; 0 {
 self.tableView.backgroundView = .none;
 return filteredContacts.count
 } else {
 Helper.EmptyMessage(message: ConstantMap.NO_CONTACT_FOUND, viewController: self)
 return 0
 }
 } else {
 if contacts.count &gt; 0 {
 self.tableView.backgroundView = .none;
 return contacts.count
 } else {
 Helper.EmptyMessage(message: ConstantMap.NO_CONTACT_FOUND, viewController: self)
 return 0
 }
 }
}
</code></pre>

Helper Class with function :

<pre><code> /* Description: This function generate alert dialog for empty message by passing message and
 associated viewcontroller for that function
 - Parameters:
 - message: message that require for empty alert message
 - viewController: selected viewcontroller at that time
 */
 static func EmptyMessage(message:String, viewController:UITableViewController) {
 let messageLabel = UILabel(frame: CGRect(x: 0, y: 0, width: viewController.view.bounds.size.width, height: viewController.view.bounds.size.height))
 messageLabel.text = message
 let bubbleColor = UIColor(red: CGFloat(57)/255, green: CGFloat(81)/255, blue: CGFloat(104)/255, alpha :1)

 messageLabel.textColor = bubbleColor
 messageLabel.numberOfLines = 0;
 messageLabel.textAlignment = .center;
 messageLabel.font = UIFont(name: "TrebuchetMS", size: 18)
 messageLabel.sizeToFit()

 viewController.tableView.backgroundView = messageLabel;
 viewController.tableView.separatorStyle = .none;
 }
</code></pre>

blocks|key|1864483|text|根据苹果，使用容器视图控制器是正确的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1864484|我把我所有的空州视图放在一个单独的故事板上。每个子类都属于自己的UIViewController子类。我直接在他们的根目录下添加内容。如果需要任何操作/按钮，您现在已经有了一个控制器来处理它。|1864485|然后，只需从Storyboard实例化所需的视图控制器，将其添加为子视图控制器，并将容器视图添加到tableView的层次结构(子视图)中。您的空状态视图也将是可滚动的，这感觉很好，并允许您实现拉刷新。|1864486|关于如何实现的帮助，朗读章节“向内容中添加子视图控制器”。|1864487|只需确保您将子视图框架设置为(0,+0,+tableView.frame.width,+tableView.frame.height)，并且事情将正确地进行居中和对齐。|style|CODE|1864488|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW1|1^0|2|2|0|0|0|0|A|2|1|0|E|1H|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|C|$]]|$1|H|3|I|5|6|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]|$1|J|3|K|5|6|7|16|8|@$A|17|B|18|L|M]]|9|@]|C|$]]|$1|N|3|-4|5|6|7|19|8|@]|9|@]|C|$]]]|O|$P|$5|Q|R|S|C|$T|U]]|V|$5|Q|R|S|C|$T|U]]]]

Using a Container View Controller is the right way to do it according to <a href="https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW1" rel="nofollow noreferrer">Apple</a>.

I put all my empty state views in a separate Storyboard. Each under it's own UIViewController subclass. I add content directly under their root view. If any action/button is needed, you now already have a controller to handle it. 
Then its just a matter of instantiating the desired view controller from that Storyboard, add it as a child view controller and add the container view to the tableView's hierarchy (sub view).
Your empty state view will be scrollable as well, which feels good and allow you to implement pull to refresh.

<a href="https://developer.apple.com/library/content/featuredarticles/ViewControllerPGforiPhoneOS/ImplementingaContainerViewController.html#//apple_ref/doc/uid/TP40007457-CH11-SW1" rel="nofollow noreferrer">Read</a> chapter 'Adding a Child View Controller to Your Content' for help on how to implement.

Just make sure you set the child view frame as 
<code>(0, 0, tableView.frame.width, tableView.frame.height)</code> and things will be centered and aligned properly.

blocks|key|2654231|text|也许这不是最好的解决方案，但我只是在表的底部添加了一个标签，如果行=0，我就给它分配一些文本。非常简单，并实现了您试图用几行代码所做的工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2654232|我的桌子上有两个部分(工作和学校)|2654233|++++func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{

++++if+(jobs.count+==+0+&&+schools.count+==+0)+{
++++++++emptyLbl.text+=+"No+jobs+or+schools"
++++}+else+{
++++++++emptyLbl.text+=+""
++++}|code-block|syntax|javascript|2654234|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Probably not the greatest solution, but I did this by just putting a label at the bottom of my table and if the rows = 0 then I assign it some text. Pretty easy, and achieves what you are trying to do with a few lines of code. 

I have two sections in my table (jobs and schools)

<pre><code> func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {

 if (jobs.count == 0 &amp;&amp; schools.count == 0) {
 emptyLbl.text = "No jobs or schools"
 } else {
 emptyLbl.text = ""
 }
</code></pre>

blocks|key|1864502|text|和Jhonston的回答一样，但我更喜欢把它作为延期：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1864503|import+UIKit

extension+UITableView+{

++++func+setEmptyMessage(_+message:+String)+{
++++++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+self.bounds.size.width,+height:+self.bounds.size.height))
++++++++messageLabel.text+=+message
++++++++messageLabel.textColor+=+.black
++++++++messageLabel.numberOfLines+=+0
++++++++messageLabel.textAlignment+=+.center
++++++++messageLabel.font+=+UIFont(name:+"TrebuchetMS",+size:+15)
++++++++messageLabel.sizeToFit()

++++++++self.backgroundView+=+messageLabel
++++++++self.separatorStyle+=+.none
++++}

++++func+restore()+{
++++++++self.backgroundView+=+nil
++++++++self.separatorStyle+=+.singleLine
++++}
}|code-block|syntax|javascript|1864504|用法：|1864505|override+func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{
++++if+things.count+==+0+{
++++++++self.tableView.setEmptyMessage("My+Message")
++++}+else+{
++++++++self.tableView.restore()
++++}

++++return+things.count
}|1864506|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Same as Jhonston's answer, but I preferred it as an extension:

<pre><code>import UIKit

extension UITableView {

 func setEmptyMessage(_ message: String) {
 let messageLabel = UILabel(frame: CGRect(x: 0, y: 0, width: self.bounds.size.width, height: self.bounds.size.height))
 messageLabel.text = message
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0
 messageLabel.textAlignment = .center
 messageLabel.font = UIFont(name: "TrebuchetMS", size: 15)
 messageLabel.sizeToFit()

 self.backgroundView = messageLabel
 self.separatorStyle = .none
 }

 func restore() {
 self.backgroundView = nil
 self.separatorStyle = .singleLine
 }
}
</code></pre>

Usage:

<pre><code>override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
 if things.count == 0 {
 self.tableView.setEmptyMessage("My Message")
 } else {
 self.tableView.restore()
 }

 return things.count
}
</code></pre>

blocks|key|543635|text|这是最好的和简单的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|543636|UIView+*view+=+[[UIView+alloc]+initWithFrame:CGRectMake(0,+0,+self.view.frame.size.width,+60)];
UILabel+*label+=+[[UILabel+alloc]+initWithFrame:CGRectMake(0,+0,+self.view.frame.size.width,+60)];
label.text+=+@"This+list+is+empty";
label.center+=+self.view.center;
label.textAlignment+=+NSTextAlignmentCenter;
[view+addSubview:label];

self.tableView.backgroundView+=+view;|code-block|syntax|javascript|543637|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is the best and simple solution.

<pre><code>UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 60)];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 60)];
label.text = @"This list is empty";
label.center = self.view.center;
label.textAlignment = NSTextAlignmentCenter;
[view addSubview:label];

self.tableView.backgroundView = view;
</code></pre>

blocks|key|2654389|text|在故事板中选择您的tableviewController场景|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2654390|​|2654391|📷|atomic|offset|length|2654392|2654393|拖放带有消息的UIView添加标签(例如:没有数据)|2654394|2654395|2654396|在您的UIView上创建yournoDataView的出口(例如yournoDataView)。|2654397|在viewDidLoad中|2654398|self.tableView.backgroundView+=+yourNoDataView|2654399|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/9b2a15f233402bd6af25f043753eb7ef.png|imageAlt|1|https://developer.qcloudimg.com/http-save/yehe-900000/3da27ccbd1301954ff82e04fcad0d19a.png^0|0|0|0|1|0|0|0|0|0|0|1|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@$G|17|H|18|1|19]]|A|$]]|$1|I|3|C|5|6|7|1A|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1B|8|@]|9|@]|A|$]]|$1|L|3|C|5|6|7|1C|8|@]|9|@]|A|$]]|$1|M|3|E|5|F|7|1D|8|@]|9|@$G|1E|H|1F|1|1G]]|A|$]]|$1|N|3|O|5|6|7|1H|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1I|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|1J|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|U|$V|$5|W|X|Y|A|$Z|10|11|-4]]|12|$5|W|X|Y|A|$Z|13|11|-4]]]]

Select your tableviewController Scene in storyboard 

<a href="https://i.stack.imgur.com/XEVxD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XEVxD.png" alt="enter image description here"></a>

Drag and drop UIView
Add label with your message (eg: No Data)

<a href="https://i.stack.imgur.com/zSeSD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zSeSD.png" alt="enter image description here"></a> 

create outlet of UIView (say for eg yournoDataView) on your TableViewController.

and in viewDidLoad 

self.tableView.backgroundView = yourNoDataView

blocks|key|543731|text|因此，为了更安全的解决办法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|543732|extension+UITableView+{
func+setEmptyMessage(_+message:+String)+{
++++guard+self.numberOfRows()+==+0+else+{
++++++++return
++++}
++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+self.bounds.size.width,+height:+self.bounds.size.height))
++++messageLabel.text+=+message
++++messageLabel.textColor+=+.black
++++messageLabel.numberOfLines+=+0;
++++messageLabel.textAlignment+=+.center;
++++messageLabel.font+=+UIFont.systemFont(ofSize:+14.0,+weight:+UIFontWeightMedium)
++++messageLabel.sizeToFit()

++++self.backgroundView+=+messageLabel;
++++self.separatorStyle+=+.none;
}

func+restore()+{
++++self.backgroundView+=+nil
++++self.separatorStyle+=+.singleLine
}

public+func+numberOfRows()+->+Int+{
++++var+section+=+0
++++var+rowCount+=+0
++++while+section+<+numberOfSections+{
++++++++rowCount+%2B=+numberOfRows(inSection:+section)
++++++++section+%2B=+1
++++}
++++return+rowCount
++}
}|code-block|syntax|javascript|543733|对于UICollectionView也是如此：|offset|length|style|CODE|543734|extension+UICollectionView+{
func+setEmptyMessage(_+message:+String)+{
++++guard+self.numberOfItems()+==+0+else+{
++++++++return
++++}

++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+self.bounds.size.width,+height:+self.bounds.size.height))
++++messageLabel.text+=+message
++++messageLabel.textColor+=+.black
++++messageLabel.numberOfLines+=+0;
++++messageLabel.textAlignment+=+.center;
++++messageLabel.font+=+UIFont.systemFont(ofSize:+18.0,+weight:+UIFontWeightSemibold)
++++messageLabel.sizeToFit()
++++self.backgroundView+=+messageLabel;
}

func+restore()+{
++++self.backgroundView+=+nil
}

public+func+numberOfItems()+->+Int+{
++++var+section+=+0
++++var+itemsCount+=+0
++++while+section+<+self.numberOfSections+{
++++++++itemsCount+%2B=+numberOfItems(inSection:+section)
++++++++section+%2B=+1
++++}
++++return+itemsCount
++}
}|543735|更通用的解决方案：|543736|++++protocol+EmptyMessageViewType+{
++++++mutating+func+setEmptyMessage(_+message:+String)
++++++mutating+func+restore()
++++}

++++protocol+ListViewType:+EmptyMessageViewType+where+Self:+UIView+{
++++++var+backgroundView:+UIView?+{+get+set+}
++++}

++++extension+UITableView:+ListViewType+{}
++++extension+UICollectionView:+ListViewType+{}

++++extension+ListViewType+{
++++++mutating+func+setEmptyMessage(_+message:+String)+{
++++++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,
+++++++++++++++++++++++++++++++++++++++++++++++++y:+0,
+++++++++++++++++++++++++++++++++++++++++++++++++width:+self.bounds.size.width,
+++++++++++++++++++++++++++++++++++++++++++++++++height:+self.bounds.size.height))
++++++++messageLabel.text+=+message
++++++++messageLabel.textColor+=+.black
++++++++messageLabel.numberOfLines+=+0
++++++++messageLabel.textAlignment+=+.center
++++++++messageLabel.font+=+UIFont(name:+"TrebuchetMS",+size:+16)
++++++++messageLabel.sizeToFit()

++++++++backgroundView+=+messageLabel
++++}

+++++mutating+func+restore()+{
++++++++backgroundView+=+nil
+++++}
}|543737|entityMap^0|0|0|2|G|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

So for a safer solution:

<pre><code>extension UITableView {
func setEmptyMessage(_ message: String) {
 guard self.numberOfRows() == 0 else {
 return
 }
 let messageLabel = UILabel(frame: CGRect(x: 0, y: 0, width: self.bounds.size.width, height: self.bounds.size.height))
 messageLabel.text = message
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0;
 messageLabel.textAlignment = .center;
 messageLabel.font = UIFont.systemFont(ofSize: 14.0, weight: UIFontWeightMedium)
 messageLabel.sizeToFit()

 self.backgroundView = messageLabel;
 self.separatorStyle = .none;
}

func restore() {
 self.backgroundView = nil
 self.separatorStyle = .singleLine
}

public func numberOfRows() -&gt; Int {
 var section = 0
 var rowCount = 0
 while section &lt; numberOfSections {
 rowCount += numberOfRows(inSection: section)
 section += 1
 }
 return rowCount
 }
}
</code></pre>

and for <code>UICollectionView</code> as well:

<pre><code>extension UICollectionView {
func setEmptyMessage(_ message: String) {
 guard self.numberOfItems() == 0 else {
 return
 }

 let messageLabel = UILabel(frame: CGRect(x: 0, y: 0, width: self.bounds.size.width, height: self.bounds.size.height))
 messageLabel.text = message
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0;
 messageLabel.textAlignment = .center;
 messageLabel.font = UIFont.systemFont(ofSize: 18.0, weight: UIFontWeightSemibold)
 messageLabel.sizeToFit()
 self.backgroundView = messageLabel;
}

func restore() {
 self.backgroundView = nil
}

public func numberOfItems() -&gt; Int {
 var section = 0
 var itemsCount = 0
 while section &lt; self.numberOfSections {
 itemsCount += numberOfItems(inSection: section)
 section += 1
 }
 return itemsCount
 }
}
</code></pre>

More Generic Solution: 

<pre><code> protocol EmptyMessageViewType {
 mutating func setEmptyMessage(_ message: String)
 mutating func restore()
 }

 protocol ListViewType: EmptyMessageViewType where Self: UIView {
 var backgroundView: UIView? { get set }
 }

 extension UITableView: ListViewType {}
 extension UICollectionView: ListViewType {}

 extension ListViewType {
 mutating func setEmptyMessage(_ message: String) {
 let messageLabel = UILabel(frame: CGRect(x: 0,
 y: 0,
 width: self.bounds.size.width,
 height: self.bounds.size.height))
 messageLabel.text = message
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0
 messageLabel.textAlignment = .center
 messageLabel.font = UIFont(name: "TrebuchetMS", size: 16)
 messageLabel.sizeToFit()

 backgroundView = messageLabel
 }

 mutating func restore() {
 backgroundView = nil
 }
}
</code></pre>

blocks|key|1864705|text|显示空列表的消息，包括它的UICollectionView.+UITableView或|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1864706|extension+UIScrollView+{
++++func+showEmptyListMessage(_+message:String)+{
++++++++let+rect+=+CGRect(origin:+CGPoint(x:+0,y+:0),+size:+CGSize(width:+self.bounds.size.width,+height:+self.bounds.size.height))
++++++++let+messageLabel+=+UILabel(frame:+rect)
++++++++messageLabel.text+=+message
++++++++messageLabel.textColor+=+.black
++++++++messageLabel.numberOfLines+=+0
++++++++messageLabel.textAlignment+=+.center
++++++++messageLabel.font+=+UIFont.systemFont(ofSize:+15)
++++++++messageLabel.sizeToFit()

++++++++if+let+`self`+=+self+as?+UITableView+{
++++++++++++self.backgroundView+=+messageLabel
++++++++++++self.separatorStyle+=+.none
++++++++}+else+if+let+`self`+=+self+as?+UICollectionView+{
++++++++++++self.backgroundView+=+messageLabel
++++++++}
++++}
}|code-block|syntax|javascript|1864707|用法：|1864708|if+cellsViewModels.count+==+0+{
++++self.tableView.showEmptyListMessage("No+Product+In+List!")
}|1864709|或：|1864710|if+cellsViewModels.count+==+0+{
++++self.collectionView?.showEmptyListMessage("No+Product+In+List!")
}|1864711|记住：不要忘记删除消息标签，以防数据在刷新后出现。|1864712|entityMap^0|D|G|V|B|0|0|0|3|0|0|0|2|0|0|0|3|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|V|$]]

Show Message for empty list, Wether its UITableView or UICollectionView. 

<pre><code>extension UIScrollView {
 func showEmptyListMessage(_ message:String) {
 let rect = CGRect(origin: CGPoint(x: 0,y :0), size: CGSize(width: self.bounds.size.width, height: self.bounds.size.height))
 let messageLabel = UILabel(frame: rect)
 messageLabel.text = message
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0
 messageLabel.textAlignment = .center
 messageLabel.font = UIFont.systemFont(ofSize: 15)
 messageLabel.sizeToFit()

 if let `self` = self as? UITableView {
 self.backgroundView = messageLabel
 self.separatorStyle = .none
 } else if let `self` = self as? UICollectionView {
 self.backgroundView = messageLabel
 }
 }
}
</code></pre>

Usages:

<pre><code>if cellsViewModels.count == 0 {
 self.tableView.showEmptyListMessage("No Product In List!")
}
</code></pre>

OR:

<pre><code>if cellsViewModels.count == 0 {
 self.collectionView?.showEmptyListMessage("No Product In List!")
}
</code></pre>

Remember:
 Don't forget to remove the message label in case data will come after refresh.

blocks|key|2654500|text|最简单和最快捷的方法是将标签拖到tableView下的侧面板上。为标签和tableView创建一个出口，并添加一个if语句，以根据需要隐藏和显示标签和表。或者，您也可以将tableView.tableFooterView+=+UIView(frame:+CGRect.zero)添加到viewDidLoad()中，以给空表以一种感觉，即如果表和背景视图具有相同的颜色，则该表是隐藏的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2654501|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The easiest and quickest way to do this is to drag a label on to side panel under tableView. Create a outlet for the label and the tableView and add a if statement to hide and show the label and table as needed. Alternatively you can add tableView.tableFooterView = UIView(frame: CGRect.zero) this to you viewDidLoad() to give an empty table the perception that it is hidden if the table and background view have the same colour.

blocks|key|543822|text|使用Swift+4.2|type|unstyled|depth|inlineStyleRanges|entityRanges|data|543823|++func+numberOfSections(in+tableView:+UITableView)+->+Int
{
++++var+numOfSections:+Int+=+0
++++if+self.medArray.count+>+0
++++{
++++++++tableView.separatorStyle+=+.singleLine
++++++++numOfSections++++++++++++=+1
++++++++tableView.backgroundView+=+nil
++++}
++++else
++++{
++++++++let+noDataLabel:+UILabel++=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+tableView.bounds.size.width,+height:+tableView.bounds.size.height))
++++++++noDataLabel.text++++++++++=+"No++Medicine+available.Press+%2B+to+add+New+Pills+"
++++++++noDataLabel.textColor+++++=+UIColor.black
++++++++noDataLabel.textAlignment+=+.center
++++++++tableView.backgroundView++=+noDataLabel
++++++++tableView.separatorStyle++=+.none
++++}
++++return+numOfSections
}|code-block|syntax|javascript|543824|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Using Swift 4.2

<pre><code> func numberOfSections(in tableView: UITableView) -&gt; Int
{
 var numOfSections: Int = 0
 if self.medArray.count &gt; 0
 {
 tableView.separatorStyle = .singleLine
 numOfSections = 1
 tableView.backgroundView = nil
 }
 else
 {
 let noDataLabel: UILabel = UILabel(frame: CGRect(x: 0, y: 0, width: tableView.bounds.size.width, height: tableView.bounds.size.height))
 noDataLabel.text = "No Medicine available.Press + to add New Pills "
 noDataLabel.textColor = UIColor.black
 noDataLabel.textAlignment = .center
 tableView.backgroundView = noDataLabel
 tableView.separatorStyle = .none
 }
 return numOfSections
}
</code></pre>

blocks|key|543908|text|我做了一些更改，这样就不需要手动检查计数了，还为标签添加了约束，这样无论消息有多大，都不会出错，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|543909|extension+UITableView+{

++++fileprivate+func+configureLabelLayout(_+messageLabel:+UILabel)+{
++++++++messageLabel.translatesAutoresizingMaskIntoConstraints+=+false
++++++++let+labelTop:+CGFloat+=+CGFloat(UIDevice.current.userInterfaceIdiom+==+.pad+?+25:15)
++++++++messageLabel.topAnchor.constraint(equalTo:+backgroundView?.topAnchor+??+NSLayoutAnchor(),+constant:+labelTop).isActive+=+true
++++++++messageLabel.widthAnchor.constraint(equalTo:+backgroundView?.widthAnchor+??+NSLayoutAnchor(),+constant:+-20).isActive+=+true
++++++++messageLabel.centerXAnchor.constraint(equalTo:+backgroundView?.centerXAnchor+??+NSLayoutAnchor(),+constant:+0).isActive+=+true
++++}

++++fileprivate+func+configureLabel(_+message:+String)+{
++++++++let+messageLabel+=+UILabel(frame:+CGRect(x:+0,+y:+0,+width:+self.bounds.size.width,+height:+self.bounds.size.height))
++++++++messageLabel.textColor+=+.black
++++++++messageLabel.numberOfLines+=+0
++++++++messageLabel.textAlignment+=+.center
++++++++let+fontSize+=+CGFloat(UIDevice.current.userInterfaceIdiom+==+.pad+?+25:15)
++++++++let+font:+UIFont+=+UIFont(name:+"MyriadPro-Regular",+size:+fontSize)+??+UIFont()
++++++++messageLabel.font+=+font
++++++++messageLabel.text+=+message
++++++++self.backgroundView+=+UIView()
++++++++self.backgroundView?.addSubview(messageLabel)
++++++++configureLabelLayout(messageLabel)
++++++++self.separatorStyle+=+.none
++++}

++++func+setEmptyMessage(_+message:+String,+_+isEmpty:+Bool)+{
++++++++if+isEmpty+{+//+instead+of+making+the+check+in+every+TableView+DataSource+in+the+project
++++++++++++configureLabel(message)
++++++++}
++++++++else+{
++++++++++++restore()
++++++++}

++++}

++++func+restore()+{
++++++++self.backgroundView+=+nil
++++++++self.separatorStyle+=+.singleLine
++++}
}|code-block|syntax|javascript|543910|使用|offset|length|style|BOLD|543911|func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{
++++++++let+message:+String+=+"The+list+is+empty."
++++++++ticketsTableView.setEmptyMessage(message,+tickets.isEmpty)
++++++++return+self.tickets.count
++++}|543912|entityMap^0|0|0|0|2|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I made a few changes so that we don't need to check on the count manually, also i added constraints for the label so that nothing goes wrong no matter how large is the message as shown below:

<pre><code>extension UITableView {

 fileprivate func configureLabelLayout(_ messageLabel: UILabel) {
 messageLabel.translatesAutoresizingMaskIntoConstraints = false
 let labelTop: CGFloat = CGFloat(UIDevice.current.userInterfaceIdiom == .pad ? 25:15)
 messageLabel.topAnchor.constraint(equalTo: backgroundView?.topAnchor ?? NSLayoutAnchor(), constant: labelTop).isActive = true
 messageLabel.widthAnchor.constraint(equalTo: backgroundView?.widthAnchor ?? NSLayoutAnchor(), constant: -20).isActive = true
 messageLabel.centerXAnchor.constraint(equalTo: backgroundView?.centerXAnchor ?? NSLayoutAnchor(), constant: 0).isActive = true
 }

 fileprivate func configureLabel(_ message: String) {
 let messageLabel = UILabel(frame: CGRect(x: 0, y: 0, width: self.bounds.size.width, height: self.bounds.size.height))
 messageLabel.textColor = .black
 messageLabel.numberOfLines = 0
 messageLabel.textAlignment = .center
 let fontSize = CGFloat(UIDevice.current.userInterfaceIdiom == .pad ? 25:15)
 let font: UIFont = UIFont(name: "MyriadPro-Regular", size: fontSize) ?? UIFont()
 messageLabel.font = font
 messageLabel.text = message
 self.backgroundView = UIView()
 self.backgroundView?.addSubview(messageLabel)
 configureLabelLayout(messageLabel)
 self.separatorStyle = .none
 }

 func setEmptyMessage(_ message: String, _ isEmpty: Bool) {
 if isEmpty { // instead of making the check in every TableView DataSource in the project
 configureLabel(message)
 }
 else {
 restore()
 }

 }

 func restore() {
 self.backgroundView = nil
 self.separatorStyle = .singleLine
 }
}
</code></pre>

Usage

<pre><code>func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
 let message: String = "The list is empty."
 ticketsTableView.setEmptyMessage(message, tickets.isEmpty)
 return self.tickets.count
 }
</code></pre>

blocks|key|1864854|text|或者，您也可以使用一些可定制的轻量级库。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1864855|SwiftEmptyState|offset|length|1864856|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/EnesKaraosman/SwiftEmptyState^0|0|0|F|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

Or alternatively you can use a bit customizable light-weight library

<a href="https://github.com/EnesKaraosman/SwiftEmptyState" rel="nofollow noreferrer">SwiftEmptyState</a>

blocks|key|2654631|text|您可以将其添加到基类中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2654632|var+messageLabel+=+UILabel()

func+showNoDataMessage(msg:+String)+{
++++let+rect+=+CGRect(origin:+CGPoint(x:+0,+y+:self.view.center.y),+size:+CGSize(width:+self.view.bounds.width+-+16,+height:+50.0))
++++messageLabel+=+UILabel(frame:+rect)
++++messageLabel.center+=+self.view.center
++++messageLabel.text+=+msg
++++messageLabel.numberOfLines+=+0
++++messageLabel.textColor+=+Colors.grayText
++++messageLabel.textAlignment+=+.center;
++++messageLabel.font+=+UIFont(name:+"Lato-Regular",+size:+17)
++++self.view.addSubview(messageLabel)
++++self.view.bringSubviewToFront(messageLabel)
}|code-block|syntax|javascript|2654633|在从api获取数据时，在类中这样显示它。|2654634|func+populateData(dataSource+:+[PRNJobDataSource]){
++++self.dataSource+=+dataSource
++++self.tblView.reloadData()
++++if+self.dataSource.count+==+0+{self.showNoDataMessage(msg:+"No+data+found.")}
}|2654635|像这样藏起来。|2654636|func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{
++++if+self.dataSource.count+>+0+{self.hideNoDataMessage()}
++++return+dataSource.count
}

func+hideNoDataMessage(){
++++messageLabel.removeFromSuperview()
}|2654637|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can add this to your Base class.

<pre><code>var messageLabel = UILabel()

func showNoDataMessage(msg: String) {
 let rect = CGRect(origin: CGPoint(x: 0, y :self.view.center.y), size: CGSize(width: self.view.bounds.width - 16, height: 50.0))
 messageLabel = UILabel(frame: rect)
 messageLabel.center = self.view.center
 messageLabel.text = msg
 messageLabel.numberOfLines = 0
 messageLabel.textColor = Colors.grayText
 messageLabel.textAlignment = .center;
 messageLabel.font = UIFont(name: "Lato-Regular", size: 17)
 self.view.addSubview(messageLabel)
 self.view.bringSubviewToFront(messageLabel)
}
</code></pre>

Show it like this in the class on getting the data from api.

<pre><code>func populateData(dataSource : [PRNJobDataSource]){
 self.dataSource = dataSource
 self.tblView.reloadData()
 if self.dataSource.count == 0 {self.showNoDataMessage(msg: "No data found.")}
}
</code></pre>

Hide it like this.

<pre><code>func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
 if self.dataSource.count &gt; 0 {self.hideNoDataMessage()}
 return dataSource.count
}

func hideNoDataMessage(){
 messageLabel.removeFromSuperview()
}
</code></pre>

blocks|key|2654779|text|对于多个数据集和节，有一个特定的用例，其中每个部分都需要一个空状态。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2654780|您可以使用这个问题的多个答案中提到的建议--提供自定义空状态单元格。|2654781|我将尝试以更详细的方式向您介绍所有的步骤，希望这会有所帮助。以下是我们可以期待的结果：|2654782|​|2654783|📷|atomic|2654784|2654785|为了简单起见，我们将处理两个数据集(两个部分)，它们将是静态的。|2654786|我还将假设您的tableView逻辑的其余部分与数据集、tabvleView单元格和部分一起正常工作。|2654787|Swift+5，让我们这样做：|2654788|1.创建自定义的空状态UITableViewCell类：|2654789|class+EmptyTableViewCell:+UITableViewCell+{

++++override+init(style:+UITableViewCell.CellStyle,+reuseIdentifier:+String?)+{
++++++++super.init(style:+style,+reuseIdentifier:+reuseIdentifier)
++++++++setupView()
++++}

++++required+init?(coder:+NSCoder)+{
++++++++fatalError("init(coder:)+has+not+been+implemented")
++++}

++++let+label:+UILabel+=+{
++++++++let+label+=+UILabel()
++++++++label.translatesAutoresizingMaskIntoConstraints+=+false
++++++++label.text+=+"Empty+State+Message"
++++++++label.font+=+.systemFont(ofSize:+16)
++++++++label.textColor+=+.gray
++++++++label.textAlignment+=+.left
++++++++label.numberOfLines+=+1
++++++++return+label
++++}()

++++private+func+setupView(){
++++++++contentView.addSubviews(label)
++++++++let+layoutGuide+=+contentView.layoutMarginsGuide
++++++++NSLayoutConstraint.activate([
++++++++++++label.leadingAnchor.constraint(equalTo:+layoutGuide.leadingAnchor),
++++++++++++label.topAnchor.constraint(equalTo:+layoutGuide.topAnchor),
++++++++++++label.bottomAnchor.constraint(equalTo:+layoutGuide.bottomAnchor),
++++++++++++label.trailingAnchor.constraint(equalTo:+layoutGuide.trailingAnchor),
++++++++++++label.heightAnchor.constraint(equalToConstant:+50)
++++++++])
++++}
}|code-block|syntax|javascript|2654790|2.在UITableViewController类中添加以下内容以注册空单元格：|2654791|class+TableViewController:+UITableViewController+{
++++...
++++let+emptyCellReuseIdentifier+=+"emptyCellReuseIdentifier"
++++...
++++override+func+viewDidLoad(){
++++++++...
++++++++tableView.register(EmptyTableViewCell.self,+forCellReuseIdentifier:+emptyCellReuseIdentifier)
++++++++...
++++}
}|2654792|3.现在让我们突出上面提到的一些假设：|2654793|class+TableViewController:+UITableViewController+{
++++//+2+Data+Sets
++++var+firstDataSet:+[String]+=+[]
++++var+secondDataSet:+[String]+=+[]

++++//+Sections+array
++++let+sections:+[SectionHeader]+=+[
++++++++.init(id:+0,+title:+"First+Section"),
++++++++.init(id:+1,+title:+"Second+Section")
++++]
++++...
++++//+MARK:+-+Table+view+data+source
++++override+func+numberOfSections(in+tableView:+UITableView)+->+Int+{
++++++++sections.count
++++}
++++override+func+tableView(_+tableView:+UITableView,+titleForHeaderInSection+section:+Int)+->+String?+{
++++++++return+sections[section].title
++++}
++++++++...
++++}

struct+SectionHeader+{
++++let+id:+Int
++++let+title:+String
}|2654794|现在，让我们向数据源中添加一些自定义逻辑，以处理本节中的空行。这里，如果数据集为空，我们将返回1行：|2654795|class+TableViewController:+UITableViewController+{
++++...
++++//+MARK:+-+Table+view+data+source
++++...
++++override+func+tableView(_+tableView:+UITableView,+numberOfRowsInSection+section:+Int)+->+Int+{
++++++++switch+section{
++++++++case+0:
++++++++++++let+numberOfRows+=+firstDataSet.isEmpty+?+1+:+firstDataSet.count
++++++++++++return+numberOfRows++++++++++
++++++++case+1:
++++++++++++let+numberOfRows+=+secondDataSet.isEmpty+?+1+:+secondDataSet.count
++++++++++++return+numberOfRows+++
++++++++default:
++++++++++++return+0
++++++++}
++++}
++++...
}|2654796|5.最后，最重要的"cellForRowAt+indexPath":|2654797|class+TableViewController:+UITableViewController+{
++++...
++++//+MARK:+-+Table+view+data+source
++++...
++++override+func+tableView(_+tableView:+UITableView,+cellForRowAt+indexPath:+IndexPath)+->+UITableViewCell+{
++++++++
++++++++//+Handle+Empty+Rows+State
++++++++switch+indexPath.section+{
++++++++case+0:
++++++++++++if+firstDataSet.isEmpty+{
++++++++++++++++if+let+cell+=+tableView.dequeueReusableCell(withIdentifier:+emptyCellReuseIdentifier)+as?+EmptyTableViewCell+{
++++++++++++++++++++cell.label.text+=+"First+Data+Set+Is+Empty"
++++++++++++++++++++return+cell
++++++++++++++++}
++++++++++++}
++++++++case+1:
++++++++++++if+secondDataSet.isEmpty+{
++++++++++++++++if+let+cell+=+tableView.dequeueReusableCell(withIdentifier:+emptyCellReuseIdentifier)+as?+EmptyTableViewCell+{
++++++++++++++++++++cell.label.text+=+"Second+Data+Set+Is+Empty"
++++++++++++++++++++return+cell
++++++++++++++++}
++++++++++++}
++++++++default:
++++++++++++break
++++++++}
++++++++
++++++++//+Handle+Existing+Data+Sets
++++++++if+let+cell+=+tableView.dequeueReusableCell(withIdentifier:+cellReuseIdentifier,+for:+indexPath)+as?+TableViewCell+{
++++++++++++switch+indexPath.section+{
++++++++++++case+0:
++++++++++++++++...
++++++++++++case+1:
++++++++++++++++...
++++++++++++default:
++++++++++++++++break
++++++++++++}
++++++++++++return+cell
++++++++}

++++++++return+UITableViewCell()
++++}
++++...
}|2654798|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/b8f5668e268cd8def7adee8bb89f76ad.png|imageAlt^0|2|7|0|0|0|0|0|1|0|0|0|0|0|0|7|0|0|S|0|0|0|14|0|0|0|J|0|0|0|0|0|Y|0|0^^$0|@$1|2|3|4|5|6|7|1R|8|@$9|1S|A|1T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1U|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|1V|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|1W|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1X|8|@]|D|@$9|1Y|A|1Z|1|20]]|E|$]]|$1|O|3|K|5|6|7|21|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|22|8|@]|D|@]|E|$]]|$1|R|3|S|5|6|7|23|8|@]|D|@]|E|$]]|$1|T|3|U|5|6|7|24|8|@$9|25|A|26|B|C]]|D|@]|E|$]]|$1|V|3|W|5|6|7|27|8|@$9|28|A|29|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|Z|7|2A|8|@]|D|@]|E|$10|11]]|$1|12|3|13|5|6|7|2B|8|@$9|2C|A|2D|B|C]]|D|@]|E|$]]|$1|14|3|15|5|Z|7|2E|8|@]|D|@]|E|$10|11]]|$1|16|3|17|5|6|7|2F|8|@$9|2G|A|2H|B|C]]|D|@]|E|$]]|$1|18|3|19|5|Z|7|2I|8|@]|D|@]|E|$10|11]]|$1|1A|3|1B|5|6|7|2J|8|@]|D|@]|E|$]]|$1|1C|3|1D|5|Z|7|2K|8|@]|D|@]|E|$10|11]]|$1|1E|3|1F|5|6|7|2L|8|@$9|2M|A|2N|B|C]]|D|@]|E|$]]|$1|1G|3|1H|5|Z|7|2O|8|@]|D|@]|E|$10|11]]|$1|1I|3|-4|5|6|7|2P|8|@]|D|@]|E|$]]]|1J|$1K|$5|1L|1M|1N|E|$1O|1P|1Q|-4]]]]

There is a specific use case for multiple data sets and sections, where you need an empty state for each section.
You can use suggestions mentioned in multiple answers to this question - provide custom empty state cell.
I'll try to walk you through all the steps programmatically in more detail and hopefully, this will be helpful. Here's the result we can expect:
<a href="https://i.stack.imgur.com/3tGYg.png" rel="noreferrer"><img src="https://i.stack.imgur.com/3tGYg.png" alt="enter image description here" /></a>
For simplicity's sake, we will work with 2 data sets (2 sections), those will be static.
I will also assume that you have the rest of your tableView logic working properly with datasets, tabvleView cells, and sections.
Swift 5, let's do it:
1. Create a custom empty state UITableViewCell class:
<pre><code>class EmptyTableViewCell: UITableViewCell {

 override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
 super.init(style: style, reuseIdentifier: reuseIdentifier)
 setupView()
 }

 required init?(coder: NSCoder) {
 fatalError(&quot;init(coder:) has not been implemented&quot;)
 }

 let label: UILabel = {
 let label = UILabel()
 label.translatesAutoresizingMaskIntoConstraints = false
 label.text = &quot;Empty State Message&quot;
 label.font = .systemFont(ofSize: 16)
 label.textColor = .gray
 label.textAlignment = .left
 label.numberOfLines = 1
 return label
 }()

 private func setupView(){
 contentView.addSubviews(label)
 let layoutGuide = contentView.layoutMarginsGuide
 NSLayoutConstraint.activate([
 label.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor),
 label.topAnchor.constraint(equalTo: layoutGuide.topAnchor),
 label.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor),
 label.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor),
 label.heightAnchor.constraint(equalToConstant: 50)
 ])
 }
}
</code></pre>
2. Add the following to your UITableViewController class to register your empty cell:
<pre><code>class TableViewController: UITableViewController {
 ...
 let emptyCellReuseIdentifier = &quot;emptyCellReuseIdentifier&quot;
 ...
 override func viewDidLoad(){
 ...
 tableView.register(EmptyTableViewCell.self, forCellReuseIdentifier: emptyCellReuseIdentifier)
 ...
 }
}
</code></pre>
3. Now let's highlight some assumptions mentioned above:
<pre><code>class TableViewController: UITableViewController {
 // 2 Data Sets
 var firstDataSet: [String] = []
 var secondDataSet: [String] = []

 // Sections array
 let sections: [SectionHeader] = [
 .init(id: 0, title: &quot;First Section&quot;),
 .init(id: 1, title: &quot;Second Section&quot;)
 ]
 ...
 // MARK: - Table view data source
 override func numberOfSections(in tableView: UITableView) -&gt; Int {
 sections.count
 }
 override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -&gt; String? {
 return sections[section].title
 }
 ...
 }

struct SectionHeader {
 let id: Int
 let title: String
}
</code></pre>
4. Now let's add some custom logic to our Data Source to handle Empty Rows in our sections.
Here we are returning 1 row if a data set is empty:
<pre><code>class TableViewController: UITableViewController {
 ...
 // MARK: - Table view data source
 ...
 override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int {
 switch section{
 case 0:
 let numberOfRows = firstDataSet.isEmpty ? 1 : firstDataSet.count
 return numberOfRows 
 case 1:
 let numberOfRows = secondDataSet.isEmpty ? 1 : secondDataSet.count
 return numberOfRows 
 default:
 return 0
 }
 }
 ...
}
</code></pre>
5. Lastly, the most important &quot;cellForRowAt indexPath&quot;:
<pre><code>class TableViewController: UITableViewController {
 ...
 // MARK: - Table view data source
 ...
 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -&gt; UITableViewCell {
 
 // Handle Empty Rows State
 switch indexPath.section {
 case 0:
 if firstDataSet.isEmpty {
 if let cell = tableView.dequeueReusableCell(withIdentifier: emptyCellReuseIdentifier) as? EmptyTableViewCell {
 cell.label.text = &quot;First Data Set Is Empty&quot;
 return cell
 }
 }
 case 1:
 if secondDataSet.isEmpty {
 if let cell = tableView.dequeueReusableCell(withIdentifier: emptyCellReuseIdentifier) as? EmptyTableViewCell {
 cell.label.text = &quot;Second Data Set Is Empty&quot;
 return cell
 }
 }
 default:
 break
 }
 
 // Handle Existing Data Sets
 if let cell = tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier, for: indexPath) as? TableViewCell {
 switch indexPath.section {
 case 0:
 ...
 case 1:
 ...
 default:
 break
 }
 return cell
 }

 return UITableViewCell()
 }
 ...
}
</code></pre>

I have a UITableView that in some cases it is legal to be empty. So instead of showing the
background image of the app, I would prefer to print a friendly message in the screen, such as:

<blockquote>
 This list is now empty
</blockquote>

What is the simplest way to do it?

Handling an empty UITableView. Print a friendly message

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个UITableView，在某些情况下为空是合法的。因此，与其显示应用程序的背景图像，我更希望在屏幕上打印一条友好的信息，例如：此列表现在为空。做这件事最简单的方法是什么？

问处理空的UITableView。打印友好的信息
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问处理空的UITableView。打印友好的信息EN