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];
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 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];
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;
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.
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;
Best Answer
This problem is a real PITA to solve. It doesn't help that the API's that work are deprecated in iOS7, or that the iOS7 replacement API's are broken. Blah!
Your solution is nice, however it uses a deprecated API (
sizeWithFont:minFontSize:actualFontSize:forWidth:lineBreakMode:
), and it's not very well encapsulated - you need to copy this code around to any cells or views where you want this behavior. On the plus side it's fairly efficient! One bug may be that the label hasn't been laid out yet when you do your calculation, but you perform your calculation based on its width.I propose that you encapsulate this behavior in a UILabel subclass. By placing the sizing calculation in an overridden
intrinsicContentSize
method the label will auto-size itself. I wrote the following, which incorporates your code that will execute on iOS6, and my version using non-deprecated API's for iOS7 or better:This implementation isn't perfect. I had to ensure using baselineAdjustment == UIBaselineAdjustmentAlignCenters, and I'm not 100% certain I understand why. And I'm not happy with the hoops I had to jump through to get an accurate text height. There's also a few pixel difference between what my calculation produces, and yours. Feel free to play with it and adjust as necessary :)
The
boundingRectWithSize:options:attributes:context
API seems pretty broken to me. While it (mostly!) correctly constrains the text to the input size, it doesn't calculate the correct height! The height it returns is based on the line-height of the supplied font, even if a scaling is in play. My guess is this is whyUILabel
doesn't have this behavior by default? My workaround is to calculate an unconstrained size where both the height and width are accurate, then use the ratio between the constrained and unconstrained widths to calculate the accurate height for the constrained size. What a PITA. There are lots of complaints in the Apple dev forums and here on SO that point out that this API has a number of issues like this.