问题:

I need to measure the pixel width of a string in Cocoa Touch. Can anyone point me to a link that explains how to do this?

回答1:

On iPhone OS it is slightly different, instead look at the NSString UIKit Additions Reference. The idea is the same as in Cocoa for Mac OS X, but there are more methods.

For single lines of text use:

- (CGSize)sizeWithFont:(UIFont *)font 
              forWidth:(CGFloat)width 
         lineBreakMode:(UILineBreakMode)lineBreakMode

And for multiline texts use:

- (CGSize)sizeWithFont:(UIFont *)font 
     constrainedToSize:(CGSize)size 
         lineBreakMode:(UILineBreakMode)lineBreakMode

The use of a UILineBreakMode as argument for single lines of text can be confusing, but this is because the line break is also used to define how to truncate the text.

回答2:

Take a look at the NSString Application Kit Additions Reference, specifically boundingRectWithSize:options:attributes:. The value returned by that routine should give you the width of your NSString.

回答3:

The above solution is now deprecated. Check this for iOS 7+

 sizeWithFont:constrainedToSize:lineBreakMode

is deprecated now. Use below code snippet,

UIFont *font=[UIFont fontWithName:@"Arial" size:16.f];

NSString *name = @"APPLE";

CGSize size = [name sizeWithAttributes:@{NSFontAttributeName:font}];