ios - Vertically align text to top within a UILabel

ID : 344

viewed : 334

Tags : ioscocoa-touchuikituilabeltext-alignmentios





Top 5 Answer for ios - Vertically align text to top within a UILabel

vote vote

96

There's no way to set the vertical-align on a UILabel, but you can get the same effect by changing the label's frame. I've made my labels orange so you can see clearly what's happening.

Here's the quick and easy way to do this:

    [myLabel sizeToFit]; 

sizeToFit to squeeze a label


If you have a label with longer text that will make more than one line, set numberOfLines to 0 (zero here means an unlimited number of lines).

    myLabel.numberOfLines = 0;     [myLabel sizeToFit]; 

Longer label text with sizeToFit


Longer Version

I'll make my label in code so that you can see what's going on. You can set up most of this in Interface Builder too. My setup is a View-Based App with a background image I made in Photoshop to show margins (20 points). The label is an attractive orange color so you can see what's going on with the dimensions.

- (void)viewDidLoad {     [super viewDidLoad];      // 20 point top and left margin. Sized to leave 20 pt at right.     CGRect labelFrame = CGRectMake(20, 20, 280, 150);     UILabel *myLabel = [[UILabel alloc] initWithFrame:labelFrame];     [myLabel setBackgroundColor:[UIColor orangeColor]];      NSString *labelText = @"I am the very model of a modern Major-General, I've information vegetable, animal, and mineral";     [myLabel setText:labelText];      // Tell the label to use an unlimited number of lines     [myLabel setNumberOfLines:0];     [myLabel sizeToFit];      [self.view addSubview:myLabel]; } 

Some limitations of using sizeToFit come into play with center- or right-aligned text. Here's what happens:

    // myLabel.textAlignment = NSTextAlignmentRight;     myLabel.textAlignment = NSTextAlignmentCenter;      [myLabel setNumberOfLines:0];     [myLabel sizeToFit]; 

enter image description here

The label is still sized with a fixed top-left corner. You can save the original label's width in a variable and set it after sizeToFit, or give it a fixed width to counter these problems:

    myLabel.textAlignment = NSTextAlignmentCenter;      [myLabel setNumberOfLines:0];     [myLabel sizeToFit];      CGRect myFrame = myLabel.frame;     // Resize the frame's width to 280 (320 - margins)     // width could also be myOriginalLabelFrame.size.width     myFrame = CGRectMake(myFrame.origin.x, myFrame.origin.y, 280, myFrame.size.height);     myLabel.frame = myFrame; 

label alignment


Note that sizeToFit will respect your initial label's minimum width. If you start with a label 100 wide and call sizeToFit on it, it will give you back a (possibly very tall) label with 100 (or a little less) width. You might want to set your label to the minimum width you want before resizing.

Correct label alignment by resizing the frame width

Some other things to note:

Whether lineBreakMode is respected depends on how it's set. NSLineBreakByTruncatingTail (the default) is ignored after sizeToFit, as are the other two truncation modes (head and middle). NSLineBreakByClipping is also ignored. NSLineBreakByCharWrapping works as usual. The frame width is still narrowed to fit to the rightmost letter.


Mark Amery gave a fix for NIBs and Storyboards using Auto Layout in the comments:

If your label is included in a nib or storyboard as a subview of the view of a ViewController that uses autolayout, then putting your sizeToFit call into viewDidLoad won't work, because autolayout sizes and positions the subviews after viewDidLoad is called and will immediately undo the effects of your sizeToFit call. However, calling sizeToFit from within viewDidLayoutSubviews will work.


My Original Answer (for posterity/reference):

This uses the NSString method sizeWithFont:constrainedToSize:lineBreakMode: to calculate the frame height needed to fit a string, then sets the origin and width.

Resize the frame for the label using the text you want to insert. That way you can accommodate any number of lines.

CGSize maximumSize = CGSizeMake(300, 9999); NSString *dateString = @"The date today is January 1st, 1999"; UIFont *dateFont = [UIFont fontWithName:@"Helvetica" size:14]; CGSize dateStringSize = [dateString sizeWithFont:dateFont          constrainedToSize:maximumSize          lineBreakMode:self.dateLabel.lineBreakMode];  CGRect dateFrame = CGRectMake(10, 10, 300, dateStringSize.height);  self.dateLabel.frame = dateFrame; 
vote vote

88

  1. Set the new text:

    myLabel.text = @"Some Text" 
  2. Set the maximum number of lines to 0 (automatic):

    myLabel.numberOfLines = 0 
  3. Set the frame of the label to the maximum size:

    myLabel.frame = CGRectMake(20,20,200,800) 
  4. Call sizeToFit to reduce the frame size so the contents just fit:

    [myLabel sizeToFit] 

The labels frame is now just high and wide enough to fit your text. The top left should be unchanged. I have tested this only with the top left-aligned text. For other alignments, you might have to modify the frame afterward.

Also, my label has word wrapping enabled.

vote vote

73

Refering to the extension solution:

for(int i=1; i< newLinesToPad; i++)      self.text = [self.text stringByAppendingString:@"\n"]; 

should be replaced by

for(int i=0; i<newLinesToPad; i++)     self.text = [self.text stringByAppendingString:@"\n "]; 

Additional space is needed in every added newline, because iPhone UILabels' trailing carriage returns seems to be ignored :(

Similarly, alignBottom should be updated too with a @" \n@%" in place of "\n@%" (for cycle initialization must be replaced by "for(int i=0..." too).

The following extension works for me:

// -- file: UILabel+VerticalAlign.h #pragma mark VerticalAlign @interface UILabel (VerticalAlign) - (void)alignTop; - (void)alignBottom; @end  // -- file: UILabel+VerticalAlign.m @implementation UILabel (VerticalAlign) - (void)alignTop {     CGSize fontSize = [self.text sizeWithFont:self.font];     double finalHeight = fontSize.height * self.numberOfLines;     double finalWidth = self.frame.size.width;    //expected width of label     CGSize theStringSize = [self.text sizeWithFont:self.font constrainedToSize:CGSizeMake(finalWidth, finalHeight) lineBreakMode:self.lineBreakMode];     int newLinesToPad = (finalHeight  - theStringSize.height) / fontSize.height;     for(int i=0; i<newLinesToPad; i++)         self.text = [self.text stringByAppendingString:@"\n "]; }  - (void)alignBottom {     CGSize fontSize = [self.text sizeWithFont:self.font];     double finalHeight = fontSize.height * self.numberOfLines;     double finalWidth = self.frame.size.width;    //expected width of label     CGSize theStringSize = [self.text sizeWithFont:self.font constrainedToSize:CGSizeMake(finalWidth, finalHeight) lineBreakMode:self.lineBreakMode];     int newLinesToPad = (finalHeight  - theStringSize.height) / fontSize.height;     for(int i=0; i<newLinesToPad; i++)         self.text = [NSString stringWithFormat:@" \n%@",self.text]; } @end 

Then call [yourLabel alignTop]; or [yourLabel alignBottom]; after each yourLabel text assignment.

vote vote

68

Just in case it's of any help to anyone, I had the same problem but was able to solve the issue simply by switching from using UILabel to using UITextView. I appreciate this isn't for everyone because the functionality is a bit different.

If you do switch to using UITextView, you can turn off all the Scroll View properties as well as User Interaction Enabled... This will force it to act more like a label.

enter image description here

vote vote

56

No muss, no fuss

@interface MFTopAlignedLabel : UILabel  @end   @implementation MFTopAlignedLabel  - (void)drawTextInRect:(CGRect) rect {     NSAttributedString *attributedText = [[NSAttributedString alloc]     initWithString:self.text attributes:@{NSFontAttributeName:self.font}];     rect.size.height = [attributedText boundingRectWithSize:rect.size                                             options:NSStringDrawingUsesLineFragmentOrigin                                             context:nil].size.height;     if (self.numberOfLines != 0) {         rect.size.height = MIN(rect.size.height, self.numberOfLines * self.font.lineHeight);     }     [super drawTextInRect:rect]; }  @end 

No muss, no Objective-c, no fuss but Swift 3:

class VerticalTopAlignLabel: UILabel {      override func drawText(in rect:CGRect) {         guard let labelText = text else {  return super.drawText(in: rect) }          let attributedText = NSAttributedString(string: labelText, attributes: [NSFontAttributeName: font])         var newRect = rect         newRect.size.height = attributedText.boundingRect(with: rect.size, options: .usesLineFragmentOrigin, context: nil).size.height          if numberOfLines != 0 {             newRect.size.height = min(newRect.size.height, CGFloat(numberOfLines) * font.lineHeight)         }          super.drawText(in: newRect)     }  } 

Swift 4.2

class VerticalTopAlignLabel: UILabel {      override func drawText(in rect:CGRect) {         guard let labelText = text else {  return super.drawText(in: rect) }          let attributedText = NSAttributedString(string: labelText, attributes: [NSAttributedString.Key.font: font])         var newRect = rect         newRect.size.height = attributedText.boundingRect(with: rect.size, options: .usesLineFragmentOrigin, context: nil).size.height          if numberOfLines != 0 {             newRect.size.height = min(newRect.size.height, CGFloat(numberOfLines) * font.lineHeight)         }          super.drawText(in: newRect)     }  } 

Top 3 video Explaining ios - Vertically align text to top within a UILabel







Related QUESTION?