UILabel sizeToFit method not working properly

问题:

I'm trying to show a long chunk of text inside a UILabel in one line. The UILabel is a subview of UIScrollView so I can scroll and see the entire UILabel.

My problem is that the sizeToFit method only partialy works.

textLabel.attributedText = attributedString;
textLabel.numberOfLines = 1;
[textLabel sizeToFit];
textScrollView.contentSize = CGSizeMake(textLabel.frame.size.width, textLabel.frame.size.height);

The UIScrollView content size gets big enough to show the entire UILable, but for a line like:

so i'll try to share some of them here every once in a while."

The UILabel shows:

so i'll try to share som...

What am I doing wrong?

回答1:

Turns out the code is just fine - but the Use Autolayout was checked. Unchecked it - everything works just great...

回答2:

If you want to achieve this with auto layout turned on it's simple. Just make sure you add numberOfLines

textLabel.adjustsFontSizeToFitWidth = YES;
textLabel.numberOfLines = 0;

回答3:

Surprisingly, if you did not put a constraint on the label's width, this would work:

[textLabel.superview layoutSubviews];

I learned this by trial and error.

回答4:

try

textLabel.adjustsFontSizeToFitWidth  = YES;
textLabel.minimumFontScale      =  0.5;  

回答5:

The most common reason for sizeToFit not working properly is the UILabel not having any autolayout constraints, for instance if you're implicitly relying on the view position remaining fixed relative to the top left. Adding any constraint at all (leading, top, centerY, anything) will fix it, presumably because it will result in layoutSubviews being called at some point, as suggested in Maxthon Chan's answer.

回答6:

Have you tried NSString sizeWithAttributes: ?

https://developer.apple.com/library/ios/documentation/UIKit/Reference/NSString_UIKit_Additions/Reference/Reference.html#//apple_ref/occ/instm/NSString/sizeWithAttributes:

回答7:

Since you have restricted your Label to show only one line of Text and truncate the rest , it is behaving the same

textLabel.attributedText = attributedString;
textLabel.numberOfLines = 0;
[textLabel sizeToFit];
textLabel.lineBreakMode = NSLineBreakByWordWrapping;
textScrollView.contentSize = CGSizeMake(textLabel.frame.size.width, textLabel.frame.size.height);

Hope it will help you