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

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忘掉有多难
忘掉有多难 2020-12-23 02:24

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

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  •  青春惊慌失措
    2020-12-23 02:43

    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

    enter image description here

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