垂直对齐UILabel中的文本（注意：使用AutoLayout） [英] Vertically align text within a UILabel (Note : Using AutoLayout)

问题描述

我正在复制问题

对于那些对使用开放源代码更舒服的人，请务必查看 TTTAttributedLabel ，您可以在其中设置标签的文本对齐到 TTTAttributedLabelVerticalAlignmentTop

---

code> UILabel 并覆盖 drawTextInRect 。

这里是一个天真的实现，你现在可以使用：

Swift

  @IBDesignable类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），
选项：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 
} 
} 
  pre> 
 
 
 Swift 3 
 
 
 
  @IBDesignable class TopAlignedLabel：UILabel {
 override func drawText（在rect中：CGRect）{
如果let stringText = text {
 let stringTextAsNSString = stringText as NSString 
 let labelStringSize = stringTextAsNSString.boundingRect（with：CGSize 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 rect）
} 
} 
 override func prepareForInterfaceBuilder（）{
 super.prepareForInterfaceBuilder（）
 layer.borderWidth = 1 
 layer.borderColor = UIColor。 black.cgColor 
} 
} 
  
 
 
 
 Objective-C 
 
 
 
  IB_DESIGNABLE 
 @interface TopAlignedLabel：UILabel 
 
 @end 
 
 @implementation TopAlignedLabel 
 
  - （void）drawTextInRect：（CGRect）rect {
 if（self.text）{
 CGSize labelStringSize = [self.text boundingRectWithSize：CGSizeMake（CGRectGetWidth ），CGFLOAT_MAX）
选项：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 
  
 
 
 
 
 
 
由于我使用了IBDesignable，你可以将这个标签添加到故事板并观看它，这是我的样子。
 
 
 
 > 
 
I am Copying the same Question asked Before Question.
I have tried the solutions given and was not able to solve it since sizetofit was not effective when I use Autolayout.



The expected display is like below.

解决方案
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 Github

For those of you more comfortable with using Open Source definitely look at TTTAttributedLabel where you can set the label's text alignment to TTTAttributedLabelVerticalAlignmentTop



The trick is to subclass UILabel and override drawTextInRect. 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:

Swift

@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
    }
}


Swift 3

  @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
    }
}


Objective-C

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




Since I used IBDesignable you can add this label to a storyboard and watch it go, this is what it looks like for me



                        
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