blocks|key|142143|text|您可以通过删除最小高度来完成此操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|142144|如果您需要标签下面的其他高度的最小高度，则可以使用容器视图，该视图根据标签内容调整大小，但使用了最小高度。|142145|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You would do that by removing the minimum height.

If you need the minimum height to something else below the label then you would use a container view that resized based on the label contents but used a minimum.

blocks|key|141116|text|您可以尝试if按钮[button+setContentVerticalAlignment:UIControlContentVerticalAlignmentTop];|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|141117|编辑：|141118|如果你只想使用label，你可以尝试这样做：|141119|https://stackoverflow.com/a/11278660/1223897|141120|entityMap|0|LINK|mutability|MUTABLE|url^0|9|22|0|0|0|0|18|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|W|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|X|8|@]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|L|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|K]]]]

You can try if button <code>[button setContentVerticalAlignment:UIControlContentVerticalAlignmentTop];</code>

Edit : 

You can try with this if you want to use label only:

<a href="https://stackoverflow.com/a/11278660/1223897">https://stackoverflow.com/a/11278660/1223897</a>

blocks|key|140012|text|自动布局仅适用于控制器的边缘/大小，而不适用于控制器content.so使用自动布局在第一行顶部显示标签文本不是一个好主意。根据我的观点，sizetofit是这样做的最佳选择。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|140013|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|$]]

Auto layout only work with edges/sizes of controller, not with controllers content.so its not a good idea to use auto layout to display your label text on top of first line.
according to me sizetofit is a best option to do so.

blocks|key|142170|text|编辑|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|142171|在我最初的回答中，我使用了标签的段落样式。事实证明，对于多行标签，这实际上阻止了标签是多行的。因此，我将其从计算中删除。有关这方面的更多信息，请参阅Github|142172|对于那些更习惯使用开源的人来说，一定要看看TTTAttributedLabel，在那里可以将标签的文本对齐方式设置为TTTAttributedLabelVerticalAlignmentTop|CODE|142173|142174|诀窍是将UILabel子类化并覆盖drawTextInRect。然后强制在标签边界的原点绘制文本。|142175|下面是一个你现在就可以使用的简单实现：|142176|斯威夫特|142177|@IBDesignable+class+TopAlignedLabel:+UILabel+{
++++override+func+drawTextInRect(rect:+CGRect)+{
++++++++if+let+stringText+=+text+{
++++++++++++let+stringTextAsNSString+=+stringText+as+NSString
++++++++++++var+labelStringSize+=+stringTextAsNSString.boundingRectWithSize(CGSizeMake(CGRectGetWidth(self.frame),+CGFloat.max),
++++++++++++++++options:+NSStringDrawingOptions.UsesLineFragmentOrigin,
++++++++++++++++attributes:+[NSFontAttributeName:+font],
++++++++++++++++context:+nil).size
++++++++++++super.drawTextInRect(CGRectMake(0,+0,+CGRectGetWidth(self.frame),+ceil(labelStringSize.height)))
++++++++}+else+{
++++++++++++super.drawTextInRect(rect)
++++++++}
++++}
++++override+func+prepareForInterfaceBuilder()+{
++++++++super.prepareForInterfaceBuilder()
++++++++layer.borderWidth+=+1
++++++++layer.borderColor+=+UIColor.blackColor().CGColor
++++}
}|code-block|syntax|javascript|142178|Swift+3|142179|++@IBDesignable+class+TopAlignedLabel:+UILabel+{
++++override+func+drawText(in+rect:+CGRect)+{
++++++++if+let+stringText+=+text+{
++++++++++++let+stringTextAsNSString+=+stringText+as+NSString
++++++++++++let+labelStringSize+=+stringTextAsNSString.boundingRect(with:+CGSize(width:+self.frame.width,height:+CGFloat.greatestFiniteMagnitude),
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++options:+NSStringDrawingOptions.usesLineFragmentOrigin,
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++attributes:+[NSFontAttributeName:+font],
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++context:+nil).size
++++++++++++super.drawText(in:+CGRect(x:0,y:+0,width:+self.frame.width,+height:ceil(labelStringSize.height)))
++++++++}+else+{
++++++++++++super.drawText(in:+rect)
++++++++}
++++}
++++override+func+prepareForInterfaceBuilder()+{
++++++++super.prepareForInterfaceBuilder()
++++++++layer.borderWidth+=+1
++++++++layer.borderColor+=+UIColor.black.cgColor
++++}
}|142180|Objective-C|142181|IB_DESIGNABLE
@interface+TopAlignedLabel+:+UILabel

@end

@implementation+TopAlignedLabel

-+(void)drawTextInRect:(CGRect)rect+{
++++if+(self.text)+{
++++++++CGSize+labelStringSize+=+[self.text+boundingRectWithSize:CGSizeMake(CGRectGetWidth(self.frame),+CGFLOAT_MAX)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++options:NSStringDrawingUsesLineFragmentOrigin+%7C+NSStringDrawingUsesFontLeading
++++++++++++++++++++++++++++++++++++++++++++++++++++++attributes:@{NSFontAttributeName:self.font}
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++context:nil].size;
++++++++[super+drawTextInRect:CGRectMake(0,+0,+ceilf(CGRectGetWidth(self.frame)),ceilf(labelStringSize.height))];
++++}+else+{
++++++++[super+drawTextInRect:rect];
++++}
}

-+(void)prepareForInterfaceBuilder+{
++++++++[super+prepareForInterfaceBuilder];
++++++++self.layer.borderWidth+=+1;
++++++++self.layer.borderColor+=+[UIColor+blackColor].CGColor;
}

@end|142182|142183|由于我使用的是IBDesignable，您可以将此标签添加到故事板并观看它的运行，这就是它在我看来的样子|142184|​|142185|📷|atomic|142186|142187|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/zallanx/TopAlignedLabelTest/pull/1|1|https://github.com/TTTAttributedLabel/TTTAttributedLabel|2|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/8e47ec79f357ea54f8a80a5cf8b35d3b.png|imageAlt^0|0|2|0|22|6|0|0|1M|12|L|I|1|0|0|4|7|H|E|0|0|0|0|0|0|0|0|0|0|0|0|1|2|0|0^^$0|@$1|2|3|4|5|6|7|1T|8|@$9|1U|A|1V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1W|8|@]|D|@$9|1X|A|1Y|1|1Z]]|E|$]]|$1|H|3|I|5|6|7|20|8|@$9|21|A|22|B|J]]|D|@$9|23|A|24|1|25]]|E|$]]|$1|K|3|-4|5|6|7|26|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|27|8|@$9|28|A|29|B|J]|$9|2A|A|2B|B|J]]|D|@]|E|$]]|$1|N|3|O|5|6|7|2C|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|2D|8|@]|D|@]|E|$]]|$1|R|3|S|5|T|7|2E|8|@]|D|@]|E|$U|V]]|$1|W|3|X|5|6|7|2F|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|T|7|2G|8|@]|D|@]|E|$U|V]]|$1|10|3|11|5|6|7|2H|8|@]|D|@]|E|$]]|$1|12|3|13|5|T|7|2I|8|@]|D|@]|E|$U|V]]|$1|14|3|-4|5|6|7|2J|8|@]|D|@]|E|$]]|$1|15|3|16|5|6|7|2K|8|@]|D|@]|E|$]]|$1|17|3|18|5|6|7|2L|8|@]|D|@]|E|$]]|$1|19|3|1A|5|1B|7|2M|8|@]|D|@$9|2N|A|2O|1|2P]]|E|$]]|$1|1C|3|18|5|6|7|2Q|8|@]|D|@]|E|$]]|$1|1D|3|-4|5|6|7|2R|8|@]|D|@]|E|$]]]|1E|$1F|$5|1G|1H|1I|E|$1J|1K]]|1L|$5|1G|1H|1I|E|$1J|1M]]|1N|$5|1O|1H|1P|E|$1Q|1R|1S|-4]]]]

Edit
In my original answer I was using the paragraph style of the label. Turns out that for multi-line labels this actually prevents the label from being multi-line. As a result I removed it from the calculation. See more about this in <a href="https://github.com/zallanx/TopAlignedLabelTest/pull/1" rel="noreferrer">Github</a>
For those of you more comfortable with using Open Source definitely look at <a href="https://github.com/TTTAttributedLabel/TTTAttributedLabel" rel="noreferrer">TTTAttributedLabel</a> where you can set the label's text alignment to <code>TTTAttributedLabelVerticalAlignmentTop</code>
<hr />
The trick is to subclass <code>UILabel</code> and override <code>drawTextInRect</code>. Then enforce that the text is drawn at the origin of the label's bounds.
Here's a naive implementation that you can use right now:
<h2>Swift</h2>
<pre><code>@IBDesignable class TopAlignedLabel: UILabel {
 override func drawTextInRect(rect: CGRect) {
 if let stringText = text {
 let stringTextAsNSString = stringText as NSString
 var labelStringSize = stringTextAsNSString.boundingRectWithSize(CGSizeMake(CGRectGetWidth(self.frame), CGFloat.max),
 options: NSStringDrawingOptions.UsesLineFragmentOrigin,
 attributes: [NSFontAttributeName: font],
 context: nil).size
 super.drawTextInRect(CGRectMake(0, 0, CGRectGetWidth(self.frame), ceil(labelStringSize.height)))
 } else {
 super.drawTextInRect(rect)
 }
 }
 override func prepareForInterfaceBuilder() {
 super.prepareForInterfaceBuilder()
 layer.borderWidth = 1
 layer.borderColor = UIColor.blackColor().CGColor
 }
}
</code></pre>
<h2>Swift 3</h2>
<pre><code> @IBDesignable class TopAlignedLabel: UILabel {
 override func drawText(in rect: CGRect) {
 if let stringText = text {
 let stringTextAsNSString = stringText as NSString
 let labelStringSize = stringTextAsNSString.boundingRect(with: CGSize(width: self.frame.width,height: CGFloat.greatestFiniteMagnitude),
 options: NSStringDrawingOptions.usesLineFragmentOrigin,
 attributes: [NSFontAttributeName: font],
 context: nil).size
 super.drawText(in: CGRect(x:0,y: 0,width: self.frame.width, height:ceil(labelStringSize.height)))
 } else {
 super.drawText(in: rect)
 }
 }
 override func prepareForInterfaceBuilder() {
 super.prepareForInterfaceBuilder()
 layer.borderWidth = 1
 layer.borderColor = UIColor.black.cgColor
 }
}
</code></pre>
<h2>Objective-C</h2>
<pre><code>IB_DESIGNABLE
@interface TopAlignedLabel : UILabel

@end

@implementation TopAlignedLabel

- (void)drawTextInRect:(CGRect)rect {
 if (self.text) {
 CGSize labelStringSize = [self.text boundingRectWithSize:CGSizeMake(CGRectGetWidth(self.frame), CGFLOAT_MAX)
 options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
 attributes:@{NSFontAttributeName:self.font}
 context:nil].size;
 [super drawTextInRect:CGRectMake(0, 0, ceilf(CGRectGetWidth(self.frame)),ceilf(labelStringSize.height))];
 } else {
 [super drawTextInRect:rect];
 }
}

- (void)prepareForInterfaceBuilder {
 [super prepareForInterfaceBuilder];
 self.layer.borderWidth = 1;
 self.layer.borderColor = [UIColor blackColor].CGColor;
}

@end
</code></pre>
<hr />
Since I used IBDesignable you can add this label to a storyboard and watch it go, this is what it looks like for me
<img src="https://i.stack.imgur.com/fMpUm.png" alt="enter image description here" />

blocks|key|2925031|text|您可以使用UITextView而不是UILabel：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2925032|取消选中“启用滚动”|2925033|取消选中“可编辑”|2925034|取消选中"Selectable“|2925035|将背景颜色设置为ClearColor|2925036|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|N|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|O|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

You can use UITextView instead of UILabel: 
Uncheck "Scrolling enabled" 
Uncheck "Editable" 
Uncheck "Selectable" 
Set background color to ClearColor

blocks|key|2712539|text|我使用了@Daniel+Golasko的解决方案，每当UILabel中的文本超过UILabel所能容纳的长度时，文本就会开始向下移动，而不是保持顶部对齐。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2712540|我更改了此行以确保文本正确对齐|2712541|++++[super+drawTextInRect:CGRectMake(0,+0,+ceilf(CGRectGetWidth(self.frame)),MIN(ceilf(labelStringSize.height),+self.frame.size.height))];|code-block|syntax|javascript|2712542|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|$]]

I used @Daniel Golasko's solution and whenever the text inside the UILabel was longer than the UILabel could contain, the text would start moving down instead of staying aligned to top.

I changed this line to make sure the text is aligned properly

<pre><code> [super drawTextInRect:CGRectMake(0, 0, ceilf(CGRectGetWidth(self.frame)),MIN(ceilf(labelStringSize.height), self.frame.size.height))];
</code></pre>

blocks|key|140098|text|如果您不受固定大小的UILabel的限制，那么只需在给定的标签上使用≥约束来更改其大小，而不是在标签内对齐文本。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|140099|​|140100|📷|atomic|140101|140102|这是使用Auto+Layout最优雅的解决方案。不过，不要忘记将numberOfLines设置为零。|140103|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/4a6fab4d0a49b353e597ccd9471041d6.png|imageAlt^0|N|X|0|0|0|1|0|0|0|W|D|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@$9|11|A|12|1|13]]|E|$]]|$1|K|3|G|5|6|7|14|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|N|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|U|V|-4]]]]

If you're not restricted by having UILabel of fixed size, instead of aligning the text within a UILabel, simply use ≥ constraint on the given label to change the size of it.

<a href="https://i.stack.imgur.com/MT0wV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/MT0wV.png" alt="enter image description here"></a>

It's the most elegant solution using Auto Layout. Don't forget to set numberOfLines to zero though.

blocks|key|2712739|text|我也遇到了同样的问题，这就是我如何解决它的。我刚刚在标签的Attribute+Inspector下编辑了基线。将其设置为“对齐中心”。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2712740|​|2712741|📷|atomic|offset|length|2712742|2712743|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/f9fa2e201211abb58c14f594a3315fe9.jpeg|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 had the same problem, and this is how I solved it. I just edited the Baseline under Attribute Inspector for the Label. Set it to "Align Centers".

<a href="https://i.stack.imgur.com/yGbs0.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/yGbs0.jpg" alt="Setting baseline to Align Centers"></a>

blocks|key|140158|text|相反，我将底部空间常量更改为优先级@250并解决了我的问题。我的标签有高度常数和<=常数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|140159|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|$]]

Instead, I changed the Bottom Space Constant to priority @250 and solved my problem. And my label has height constant with &lt;= constant

blocks|key|2925342|text|我有一个类似的问题，有3个标签。中间的标签可能比其他两个标签的文本长得多，因此它的高度可能会变得更大。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2925343|如下所示：|2925344|​|2925345|📷|atomic|offset|length|2925346|2925347|我将中间标签的底部空间约束设置为>=底部标签。|2925348|2925349|2925350|2925351|这解决了我的问题。|2925352|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/fcc3ffd24d786ef0652ae4f87f43ab55.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/0058c1d39c84ea09324d2d44424f2521.png^0|0|0|0|0|1|0|0|0|0|0|0|1|1|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|14|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|15|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|16|8|@]|9|@$I|17|J|18|1|19]]|A|$]]|$1|K|3|E|5|6|7|1A|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|1B|8|@]|9|@]|A|$]]|$1|N|3|E|5|6|7|1C|8|@]|9|@]|A|$]]|$1|O|3|G|5|H|7|1D|8|@]|9|@$I|1E|J|1F|1|1G]]|A|$]]|$1|P|3|E|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z|10|-4]]|11|$5|V|W|X|A|$Y|12|10|-4]]]]

I had a similiar issue where there were 3 labels. The middle label could have much longer text than the other two, so its height could grow much larger. 

Like this:

<a href="https://i.stack.imgur.com/O2Pl3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/O2Pl3.png" alt="enter image description here"></a>

I set the middle label's bottom space constraint to be >= the bottom label.

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

That solved my problem.

blocks|key|140192|text|对我来说，我没有设置高度限制，文本总是从标签的顶部开始增长。此标签的约束为上、左、右。顺便说一下，我的标签有固定的行号，所以不用担心高度。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|140193|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|$]]

For me, I didn't set the height constraint, the text always grows from the top of the label.
The constraints for this label are top, left, right.
By the way, my label has fixed line numbers, so no worries about the height.

blocks|key|142377|text|++@IBInspectable+var+alignTop:+Bool+=+false

++func+setAlignTop()+{
++++let+text+=+self.text!
++++let+lines+=+text.characters.split(separator:+"\n").count
++++if+lines+<+self.numberOfLines+{
++++++var+newLines+=+""
++++++for+_+in+0..<(self.numberOfLines+-+lines)+{
++++++++newLines+=+newLines.appending("\n+")
++++++}
++++++self.text!+=+text.appending(newLines)
++++}
++}

++override+var+text:+String?+{
++++didSet+{
++++++if+alignTop+{
++++++++self.setAlignTop()
++++++}
++++}
++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|142378|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> @IBInspectable var alignTop: Bool = false

 func setAlignTop() {
 let text = self.text!
 let lines = text.characters.split(separator: "\n").count
 if lines &lt; self.numberOfLines {
 var newLines = ""
 for _ in 0..&lt;(self.numberOfLines - lines) {
 newLines = newLines.appending("\n ")
 }
 self.text! = text.appending(newLines)
 }
 }

 override var text: String? {
 didSet {
 if alignTop {
 self.setAlignTop()
 }
 }
 }
</code></pre>

blocks|key|2925425|text|这是Daniel+Galasko对Swift+3解决方案的改进(这里你也可以设置最大行数，而不需要在顶部设置偏移量)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2925426|import+UIKit

@IBDesignable+class+TopAlignedLabel:+UILabel+{
++++override+func+drawText(in+rect:+CGRect)+{
++++++++if+let+stringText+=+text+{
++++++++++++let+stringTextAsNSString+=+stringText+as+NSString
++++++++++++let+labelString+=+stringTextAsNSString.boundingRect(with:+CGSize(width:+frame.width,+height:+.greatestFiniteMagnitude),
++++++++++++++++++++options:+.usesLineFragmentOrigin,+attributes:+[NSFontAttributeName:+font],+context:+nil)
++++++++++++super.drawText(in:+CGRect(x:+0,+y:+0,+width:+frame.width,+height:+ceil(labelString.size.height)+>+frame.height+?+frame.height+:+ceil(labelString.size.height)))
++++++++}+else+{
++++++++++++super.drawText(in:+rect)
++++++++}
++++}

++++override+func+prepareForInterfaceBuilder()+{
++++++++super.prepareForInterfaceBuilder()
++++++++layer.borderWidth+=+1
++++++++layer.borderColor+=+UIColor.black.cgColor
++++}
}|code-block|syntax|javascript|2925427|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 an improvement on the Swift 3 solution by Daniel Galasko (here you can also set the maximum line number without an offset on the top):

<pre><code>import UIKit

@IBDesignable class TopAlignedLabel: UILabel {
 override func drawText(in rect: CGRect) {
 if let stringText = text {
 let stringTextAsNSString = stringText as NSString
 let labelString = stringTextAsNSString.boundingRect(with: CGSize(width: frame.width, height: .greatestFiniteMagnitude),
 options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
 super.drawText(in: CGRect(x: 0, y: 0, width: frame.width, height: ceil(labelString.size.height) &gt; frame.height ? frame.height : ceil(labelString.size.height)))
 } else {
 super.drawText(in: rect)
 }
 }

 override func prepareForInterfaceBuilder() {
 super.prepareForInterfaceBuilder()
 layer.borderWidth = 1
 layer.borderColor = UIColor.black.cgColor
 }
}
</code></pre>

blocks|key|2712944|text|对于标签的高度不需要恒定的情况，有一个简单的解决方案:将Label放在Stack+View中。确保将前导常量和尾随常量添加到Stack+View。以下是如何在故事板中执行此操作的截图：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2712945|​|2712946|📷|atomic|2712947|2712948|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/2cb6e485be6a1322e98a92fb07efbba0.png|imageAlt^0|S|5|Z|A|1Q|A|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@$9|13|A|14|1|15]]|E|$]]|$1|K|3|G|5|6|7|16|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|S|T|-4]]]]

There is an easy solution for cases where the height of a label doesn't need to be constant: put your <code>Label</code> in a <code>Stack View</code>. Be sure to add leading and trailing constants to the <code>Stack View</code>. Here is a screenshot of how to do it in storyboard:

<a href="https://i.stack.imgur.com/1AJDT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1AJDT.png" alt="enter image description here"></a>

blocks|key|2925465|text|使用这个我的类，你可以通过contentMode改变+alignment。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2925466|2925467|支持的案例：.top、.bottom、.left、.right、.topLeft、.topRight、.bottomLeft、.bottomRight|blockquote|2925468|2925469|2925470|Swift4|BOLD|2925471|import+Foundation
import+UIKit

@IBDesignable
class+UIAlignedLabel:+UILabel+{

++++override+func+drawText(in+rect:+CGRect)+{
++++++++if+let+text+=+text+as+NSString?+{
++++++++++++func+defaultRect(for+maxSize:+CGSize)+->+CGRect+{
++++++++++++++++let+size+=+text
++++++++++++++++++++.boundingRect(
++++++++++++++++++++++++with:+maxSize,
++++++++++++++++++++++++options:+NSStringDrawingOptions.usesLineFragmentOrigin,
++++++++++++++++++++++++attributes:+[
++++++++++++++++++++++++++++NSAttributedStringKey.font:+font
++++++++++++++++++++++++],
++++++++++++++++++++++++context:+nil
++++++++++++++++++++).size
++++++++++++++++let+rect+=+CGRect(
++++++++++++++++++++origin:+.zero,
++++++++++++++++++++size:+CGSize(
++++++++++++++++++++++++width:+min(frame.width,+ceil(size.width)),
++++++++++++++++++++++++height:+min(frame.height,+ceil(size.height))
++++++++++++++++++++)
++++++++++++++++)
++++++++++++++++return+rect

++++++++++++}
++++++++++++switch+contentMode+{
++++++++++++case+.top,+.bottom,+.left,+.right,+.topLeft,+.topRight,+.bottomLeft,+.bottomRight:
++++++++++++++++let+maxSize+=+CGSize(width:+frame.width,+height:+frame.height)
++++++++++++++++var+rect+=+defaultRect(for:+maxSize)
++++++++++++++++switch+contentMode+{
++++++++++++++++++++case+.bottom,+.bottomLeft,+.bottomRight:
++++++++++++++++++++++++rect.origin.y+=+frame.height+-+rect.height
++++++++++++++++++++default:+break
++++++++++++++++}
++++++++++++++++switch+contentMode+{
++++++++++++++++++++case+.right,+.topRight,+.bottomRight:
++++++++++++++++++++++++rect.origin.x+=+frame.width+-+rect.width
++++++++++++++++++++default:+break
++++++++++++++++}
++++++++++++++++super.drawText(in:+rect)
++++++++++++default:
++++++++++++++++super.drawText(in:+rect)
++++++++++++}
++++++++}+else+{
++++++++++++super.drawText(in:+rect)
++++++++}
++++}

}|code-block|syntax|javascript|2925472|entityMap^0|D|B|R|9|0|0|0|0|0|0|6|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|10|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|11|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|12|8|@]|D|@]|E|$]]|$1|K|3|-4|5|6|7|13|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|14|8|@$9|15|A|16|B|N]]|D|@]|E|$]]|$1|O|3|P|5|Q|7|17|8|@]|D|@]|E|$R|S]]|$1|T|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|U|$]]

use this my class, you can change text <code>alignment</code> by <code>contentMode</code>. 

<blockquote>
 supported case: .top, .bottom, .left, .right, .topLeft, .topRight, .bottomLeft, .bottomRight
</blockquote>

Swift4

<pre><code>import Foundation
import UIKit

@IBDesignable
class UIAlignedLabel: UILabel {

 override func drawText(in rect: CGRect) {
 if let text = text as NSString? {
 func defaultRect(for maxSize: CGSize) -&gt; CGRect {
 let size = text
 .boundingRect(
 with: maxSize,
 options: NSStringDrawingOptions.usesLineFragmentOrigin,
 attributes: [
 NSAttributedStringKey.font: font
 ],
 context: nil
 ).size
 let rect = CGRect(
 origin: .zero,
 size: CGSize(
 width: min(frame.width, ceil(size.width)),
 height: min(frame.height, ceil(size.height))
 )
 )
 return rect

 }
 switch contentMode {
 case .top, .bottom, .left, .right, .topLeft, .topRight, .bottomLeft, .bottomRight:
 let maxSize = CGSize(width: frame.width, height: frame.height)
 var rect = defaultRect(for: maxSize)
 switch contentMode {
 case .bottom, .bottomLeft, .bottomRight:
 rect.origin.y = frame.height - rect.height
 default: break
 }
 switch contentMode {
 case .right, .topRight, .bottomRight:
 rect.origin.x = frame.width - rect.width
 default: break
 }
 super.drawText(in: rect)
 default:
 super.drawText(in: rect)
 }
 } else {
 super.drawText(in: rect)
 }
 }

}
</code></pre>

blocks|key|2712962|text|Swift+4|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2712963|您应该继承UILabel的子类，并重写文本显示呈现。|2712964|class+UITopAlignedLabel:+UILabel+{
++++override+func+drawText(in+rect:+CGRect)+{
++++++++guard+let+string+=+text+else+{
++++++++++++super.drawText(in:+rect)
++++++++++++return
++++++++}

++++++++let+size+=+(string+as+NSString).boundingRect(
++++++++++++with:+CGSize(width:+rect.width,+height:+.greatestFiniteMagnitude),
++++++++++++options:+[.usesLineFragmentOrigin],
++++++++++++attributes:+[.font:+font],
++++++++++++context:+nil).size

++++++++var+rect+=+rect
++++++++rect.size.height+=+size.height.rounded()
++++++++super.drawText(in:+rect)
++++}
}|code-block|syntax|javascript|2712965|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|$]]

<h2>Swift 4</h2>

You should subclass UILabel and override text display rendering.

<pre><code>class UITopAlignedLabel: UILabel {
 override func drawText(in rect: CGRect) {
 guard let string = text else {
 super.drawText(in: rect)
 return
 }

 let size = (string as NSString).boundingRect(
 with: CGSize(width: rect.width, height: .greatestFiniteMagnitude),
 options: [.usesLineFragmentOrigin],
 attributes: [.font: font],
 context: nil).size

 var rect = rect
 rect.size.height = size.height.rounded()
 super.drawText(in: rect)
 }
}
</code></pre>

blocks|key|142446|text|在界面生成器中，只需将height+<=设置为某个值，而不是=。这将使to文本从顶部开始，并根据需要扩展高度。例如，我有一个高度与主视图大小成比例的标签。所以我的高度约束是这样的：Height+Constraint|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|142447|entityMap|0|LINK|mutability|MUTABLE|url|https://i.stack.imgur.com/Nd7lP.png^0|2I|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

In the Interface Builder, just make the height &lt;= some value instead of =. This will enable to text to start at the top and expand the height as needed. For example, I have a label with a height proportional to the size of the main view. So my height constraint looks like this: 
<a href="https://i.stack.imgur.com/Nd7lP.png" rel="nofollow noreferrer">Height Constraint</a>

I am Copying the same Question asked Before <a href="https://stackoverflow.com/questions/1054558/vertically-align-text-within-a-uilabel">Question</a>.
I have tried the solutions given and was not able to solve it since sizetofit was not effective when I use Autolayout.

<img src="https://i.stack.imgur.com/656W8.jpg" alt="first screenshot">

The expected display is like below.

<img src="https://i.stack.imgur.com/RWPg7.png" alt="second screenshot">

Vertically align text within a UILabel (Note : Using AutoLayout)

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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我正在复制之前问过的相同问题。我已经尝试了给出的解决方案，但无法解决它，因为当我使用自动布局时，sizetofit是无效的。​​预期的显示如下所示。​​

问在UILabel中垂直对齐文本(注意:使用AutoLayout)
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