Set the line break mode to word-wrapping and the number of lines to 0
:
// Swift
textLabel.lineBreakMode = .byWordWrapping
textLabel.numberOfLines = 0
// Objective-C
textLabel.lineBreakMode = NSLineBreakByWordWrapping;
textLabel.numberOfLines = 0;
// C# (Xamarin.iOS)
textLabel.LineBreakMode = UILineBreakMode.WordWrap;
textLabel.Lines = 0;
Restored old answer (for reference and devs willing to support iOS below 6.0):
textLabel.lineBreakMode = UILineBreakModeWordWrap;
textLabel.numberOfLines = 0;
On the side: both enum values yield to 0
anyway.
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
Here is a better answer I think. Whenever the shouldChangeTextInRange delegate method is called we call our doesFit:string:range function to see whether the resulting text height exceeds the view height. If it does we return NO to prevent the change from taking place.
EDIT OK you will also need to add some checks if you change the format of the text. In my case the user can change the font or make it bold, change paragraph style, etc.. So now any of these changes could also cause the text to exceed the textView borders.
So first you need to make sure you are registering these changes with the textViews undoManager. See below for an example (I just copy the whole attributedString so I can put it back if undo is called).
Now check the size in the delegate and undo if it does not fit.