blocks|key|5544486|text|我们根据单元格是否是第一个单元格使用自定义背景图像...中间单元格或最后一个单元格。这样我们就可以看到整张桌子的圆角。当行被选中时，它会换出一个漂亮的“突出显示”单元格，向用户反馈他们已经选择了一个单元格。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5544487|UIImage+*rowBackground;
UIImage+*selectionBackground;
NSInteger+sectionRows+=+[tableView+numberOfRowsInSection:[indexPath+section]];
NSInteger+row+=+[indexPath+row];

if+(row+==+0+&&+row+==+sectionRows+-+1)
{
++++rowBackground+=+[UIImage+imageNamed:@"topAndBottomRow.png"];
++++selectionBackground+=+[UIImage+imageNamed:@"topAndBottomRowSelected.png"];
}
else+if+(row+==+0)
{
++++rowBackground+=+[UIImage+imageNamed:@"topRow.png"];
++++selectionBackground+=+[UIImage+imageNamed:@"topRowSelected.png"];
}
else+if+(row+==+sectionRows+-+1)
{
++++rowBackground+=+[UIImage+imageNamed:@"bottomRow.png"];
++++selectionBackground+=+[UIImage+imageNamed:@"bottomRowSelected.png"];
}
else
{
++++rowBackground+=+[UIImage+imageNamed:@"middleRow.png"];
++++selectionBackground+=+[UIImage+imageNamed:@"middleRowSelected.png"];
}


((UIImageView+*)cell.backgroundView).image+=+rowBackground;
((UIImageView+*)cell.selectedBackgroundView).image+=+selectionBackground;|code-block|syntax|javascript|5544488|如果您希望使用自定义背景，只需将第一个单元格设置为indexPath.row+==+0即可。|5544489|这是从Matt+Gallagher的excellent+site派生的|offset|length|5544490|entityMap|0|LINK|mutability|MUTABLE|url|http://cocoawithlove.com/^0|0|0|0|I|E|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]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|X|8|@]|9|@$K|Y|L|Z|1|10]]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

We use custom background images for the cell based on whether or not it is the first cell... a middle cell or the last cell. That way we get a nice rounded corner look to the whole table. When the row is selected, it swaps out a nice 'highlighted' cell to give the user feed back that they have selected a cell.

<pre><code>UIImage *rowBackground;
UIImage *selectionBackground;
NSInteger sectionRows = [tableView numberOfRowsInSection:[indexPath section]];
NSInteger row = [indexPath row];

if (row == 0 &amp;&amp; row == sectionRows - 1)
{
 rowBackground = [UIImage imageNamed:@"topAndBottomRow.png"];
 selectionBackground = [UIImage imageNamed:@"topAndBottomRowSelected.png"];
}
else if (row == 0)
{
 rowBackground = [UIImage imageNamed:@"topRow.png"];
 selectionBackground = [UIImage imageNamed:@"topRowSelected.png"];
}
else if (row == sectionRows - 1)
{
 rowBackground = [UIImage imageNamed:@"bottomRow.png"];
 selectionBackground = [UIImage imageNamed:@"bottomRowSelected.png"];
}
else
{
 rowBackground = [UIImage imageNamed:@"middleRow.png"];
 selectionBackground = [UIImage imageNamed:@"middleRowSelected.png"];
}


((UIImageView *)cell.backgroundView).image = rowBackground;
((UIImageView *)cell.selectedBackgroundView).image = selectionBackground;
</code></pre>

If you wish just make the first cell, that which is at indexPath.row == 0, to use a custom background.

This is derived from Matt Gallagher's <a href="http://cocoawithlove.com/" rel="nofollow noreferrer">excellent site</a>

blocks|key|5544498|text|-+(void)viewDidAppear:(BOOL)animated+{
++++[super+viewDidAppear:animated];
++++NSIndexPath+*indexPath=[NSIndexPath+indexPathForRow:0+inSection:0];
++++[myTableView+selectRowAtIndexPath:indexPath+animated:YES++scrollPosition:UITableViewScrollPositionBottom];
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|5544499|在您的代码中使用它的最好方法是，如果您想默认选择任何行，请使用in+viewDidAppear。|unstyled|5544500|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>- (void)viewDidAppear:(BOOL)animated {
 [super viewDidAppear:animated];
 NSIndexPath *indexPath=[NSIndexPath indexPathForRow:0 inSection:0];
 [myTableView selectRowAtIndexPath:indexPath animated:YES scrollPosition:UITableViewScrollPositionBottom];
}
</code></pre>

The best way to use this in your code, if you want to select any row by default, use in viewDidAppear.

blocks|key|2016561|text|-+(void)viewWillAppear:(BOOL)animated
++++{

+++++++[super+viewWillAppear:animated];

+++++//+assuming+you+had+the+table+view+wired+to+IBOutlet+myTableView

++++++++//+and+that+you+wanted+to+select+the+first+item+in+the+first+section

++++++++[myTableView+selectRowAtIndexPath:[NSIndexPath+indexPathForRow:0+inSection:0]+animated:NO+scrollPosition:0];
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2016562|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>- (void)viewWillAppear:(BOOL)animated
 {

 [super viewWillAppear:animated];

 // assuming you had the table view wired to IBOutlet myTableView

 // and that you wanted to select the first item in the first section

 [myTableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] animated:NO scrollPosition:0];
 }
</code></pre>

blocks|key|1625185|text|-+(void)viewDidLoad
{
++++[super+viewDidLoad];
++++self.detailViewController+=+(DetailViewController+*)[[self.splitViewController.viewControllers+lastObject]+topViewController];

++++if([UIDevice+currentDevice].userInterfaceIdiom+==+UIUserInterfaceIdiomPad){
++++++++NSIndexPath*+indexPath+=+[NSIndexPath+indexPathForRow:0+inSection:0];
++++++++[self.tableView+selectRowAtIndexPath:indexPath+animated:NO+scrollPosition:UITableViewScrollPositionTop];
++++++++[self+tableView:self.tableView+didSelectRowAtIndexPath:indexPath];
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1625186|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>- (void)viewDidLoad
{
 [super viewDidLoad];
 self.detailViewController = (DetailViewController *)[[self.splitViewController.viewControllers lastObject] topViewController];

 if([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad){
 NSIndexPath* indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
 [self.tableView selectRowAtIndexPath:indexPath animated:NO scrollPosition:UITableViewScrollPositionTop];
 [self tableView:self.tableView didSelectRowAtIndexPath:indexPath];
 }
}
</code></pre>

blocks|key|5544516|text|以下是如何在Swift+1.2中执行此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5544517|override+func+viewWillAppear(animated:+Bool)+{
++++let+firstIndexPath+=+NSIndexPath(forRow:+0,+inSection:+0)
++++self.tableView.selectRowAtIndexPath(firstIndexPath,+animated:+true,+scrollPosition:+.Top)
}|code-block|syntax|javascript|5544518|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|$]]

Here's how to do this in Swift 1.2:

<pre><code>override func viewWillAppear(animated: Bool) {
 let firstIndexPath = NSIndexPath(forRow: 0, inSection: 0)
 self.tableView.selectRowAtIndexPath(firstIndexPath, animated: true, scrollPosition: .Top)
}
</code></pre>

blocks|key|2016588|text|要在第一次加载表时只选择第一个单元格，人们可能会认为使用viewDidLoad是正确的选择，但是，在执行时，表还没有加载其内容，所以它不会工作(并且可能会使应用程序崩溃，因为NSIndexPath将指向一个不存在的单元格)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|2016589|一种解决方法是使用一个变量，该变量指示表以前已加载，并相应地执行此工作。|2016590|@implementation+MyClass+{
++++BOOL+_tableHasBeenShownAtLeastOnce;
}

-+(void)viewDidLoad
{
++++[super+viewDidLoad];
++++_tableHasBeenShownAtLeastOnce+=+NO;+//+Only+on+first+run
}

-+(void)viewDidAppear:(BOOL)animated
{
++++[super+viewDidAppear:animated];

++++if+(+!+_tableHasBeenShownAtLeastOnce+)
++++{
++++++++_tableHasBeenShownAtLeastOnce+=+YES;
++++++++BOOL+animationEnabledForInitialFirstRowSelect+=+YES;+//+Whether+to+animate+the+selection+of+the+first+row+or+not...+in+viewDidAppear:,+it+should+be+YES+(to+"smooth"+it).+If+you+use+this+same+technique+in+viewWillAppear:+then+"YES"+has+no+point,+since+the+view+hasn't+appeared+yet.
++++++++NSIndexPath+*indexPathForFirstRow+=+[NSIndexPath+indexPathForRow:0+inSection:+0];

++++++++[self.tableView+selectRowAtIndexPath:indexPathForFirstRow+animated:animationEnabledForInitialFirstRowSelect+scrollPosition:UITableViewScrollPositionTop];
++++}
}

/*+More+Objective-C...+*/

@end|code-block|syntax|javascript|2016591|entityMap^0|S|B|2F|B|1A|2|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|W|8|@]|E|@]|F|$]]|$1|I|3|J|5|K|7|X|8|@]|E|@]|F|$L|M]]|$1|N|3|-4|5|6|7|Y|8|@]|E|@]|F|$]]]|O|$]]

To only select the first cell the first time the table is loaded, one would think that using <code>viewDidLoad</code> is the right place to go, but, at that time of execution, the table hasn't loaded its contents, so it will not work (and probably crash the app since the <code>NSIndexPath</code> will point to a non-existent cell).

A workaround is to use a variable that indicates that the table has loaded before and do the work accordingly.

<pre><code>@implementation MyClass {
 BOOL _tableHasBeenShownAtLeastOnce;
}

- (void)viewDidLoad
{
 [super viewDidLoad];
 _tableHasBeenShownAtLeastOnce = NO; // Only on first run
}

- (void)viewDidAppear:(BOOL)animated
{
 [super viewDidAppear:animated];

 if ( ! _tableHasBeenShownAtLeastOnce )
 {
 _tableHasBeenShownAtLeastOnce = YES;
 BOOL animationEnabledForInitialFirstRowSelect = YES; // Whether to animate the selection of the first row or not... in viewDidAppear:, it should be YES (to "smooth" it). If you use this same technique in viewWillAppear: then "YES" has no point, since the view hasn't appeared yet.
 NSIndexPath *indexPathForFirstRow = [NSIndexPath indexPathForRow:0 inSection: 0];

 [self.tableView selectRowAtIndexPath:indexPathForFirstRow animated:animationEnabledForInitialFirstRowSelect scrollPosition:UITableViewScrollPositionTop];
 }
}

/* More Objective-C... */

@end
</code></pre>

blocks|key|1625209|text|Swit+3.0更新的解决方案|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1625210|let+indexPath+=+IndexPath(row:+0,+section:+0)
tblView.selectRow(at:+indexPath,+animated:+true,+scrollPosition:+.bottom)|code-block|syntax|javascript|1625211|entityMap^0|0|F|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Swit 3.0 updated Solution

<pre><code>let indexPath = IndexPath(row: 0, section: 0)
tblView.selectRow(at: indexPath, animated: true, scrollPosition: .bottom)
</code></pre>

blocks|key|4126889|text|我对swift+3.0的解决方案是：：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|4126890|var+selectedDefaultIndexPath+=+false


override+func+viewDidAppear(_+animated:+Bool)+{
++++super.viewDidAppear(animated)

++++if+dataSource.isEmpty+==+false,+selectedDefaultIndexPath+==+false+{
++++++++let+indexPath+=+IndexPath(row:+0,+section:+0)
++++++++//+if+have+not+this,+cell.backgroundView+will+nil.
++++++++tableView.selectRow(at:+indexPath,+animated:+false,+scrollPosition:+.none)
++++++++//+trigger+delegate+to+do+something.
++++++++_+=+tableView.delegate?.tableView?(tableView,+willSelectRowAt:+indexPath)
++++++++selectedDefaultIndexPath+=+true
++++}
}

func+tableView(_+tableView:+UITableView,+willSelectRowAt+indexPath:+IndexPath)+->+IndexPath?+{
++++let+cell+=+tableView.cellForRow(at:+indexPath)
++++cell?.selectedBackgroundView?.backgroundColor+=+UIColor(hexString:+"#F0F0F0")

++++return+indexPath
}|code-block|syntax|javascript|4126891|entityMap^0|I|1|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Here is my solution for swift 3.0:

<pre class="lang-swift prettyprint-override"><code>var selectedDefaultIndexPath = false


override func viewDidAppear(_ animated: Bool) {
 super.viewDidAppear(animated)

 if dataSource.isEmpty == false, selectedDefaultIndexPath == false {
 let indexPath = IndexPath(row: 0, section: 0)
 // if have not this, cell.backgroundView will nil.
 tableView.selectRow(at: indexPath, animated: false, scrollPosition: .none)
 // trigger delegate to do something.
 _ = tableView.delegate?.tableView?(tableView, willSelectRowAt: indexPath)
 selectedDefaultIndexPath = true
 }
}

func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -&gt; IndexPath? {
 let cell = tableView.cellForRow(at: indexPath)
 cell?.selectedBackgroundView?.backgroundColor = UIColor(hexString: "#F0F0F0")

 return indexPath
}
</code></pre>

blocks|key|1625237|text|Swift+4更新：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1625238|func+viewDidAppear(_+animated:+Bool)+{
++++super.viewDidAppear(animated)
++++let+indexPath+=+IndexPath(row:+0,+section:+0)
++++myTableView.selectRow(at:+indexPath,+animated:+true,+scrollPosition:+.bottom)
}|code-block|syntax|javascript|1625239|如果要选择不同区段中的任何其他行，请更改行值和区段值。|1625240|entityMap^0|0|A|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Swift 4 Update:

<pre><code>func viewDidAppear(_ animated: Bool) {
 super.viewDidAppear(animated)
 let indexPath = IndexPath(row: 0, section: 0)
 myTableView.selectRow(at: indexPath, animated: true, scrollPosition: .bottom)
}
</code></pre>

Change row and section values if you want to select any other row in a different section.

blocks|key|2016699|text|Swift+5.x更新：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2016700|override+func+viewDidAppear(_+animated:+Bool)+{
++++super.viewDidAppear(animated)
++++let+indexPath+=+IndexPath(row:+0,+section:+0)
++++tableView.selectRow(at:+indexPath,+animated:+true,+scrollPosition:+.bottom)
++++tableView.delegate?.tableView?(tableView,+didSelectRowAt:+indexPath)
}|code-block|syntax|javascript|2016701|entityMap^0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Swift 5.x Update:
<pre><code>override func viewDidAppear(_ animated: Bool) {
 super.viewDidAppear(animated)
 let indexPath = IndexPath(row: 0, section: 0)
 tableView.selectRow(at: indexPath, animated: true, scrollPosition: .bottom)
 tableView.delegate?.tableView?(tableView, didSelectRowAt: indexPath)
}
</code></pre>

I have an application that is viewbased and I am adding a tableview as a subview to the main view. I have taken <code>UITableViewDelegate</code> to respond the table methods. Everything is working fine, but I want to select the first row or <code>UITableView</code> as default selected(Highlighted).

Please help me, with what code I need and where I need to put it.

Select First Row as default in UITableView

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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我有一个基于视图的应用程序，我正在添加一个表视图作为主视图的子视图。我使用了UITableViewDelegate来响应表格方法。一切正常，但我想选择第一行或UITableView作为默认选择(突出显示)。请帮助我，我需要什么代码，我需要把它放在哪里。

问在UITableView中选择第一行作为默认值
EN

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问在UITableView中选择第一行作为默认值EN