在 UITextView 上设置 NSAttributedString 的字体时不考虑行间距

我试图在 iOS6中将一个属性化字符串设置为 UITextView。问题是，如果尝试在属性化字符串上设置 font 属性，则忽略行间距。但是，如果我不设置字体，并且使用了默认字体，那么行间距就可以工作。

NSString *string = @" Hello \n world";
attrString = [[NSMutableAttributedString alloc] initWithString:string];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy];


paragraphStyle.minimumLineHeight = 50;
// setting the font below makes line spacing become ignored
[attrString addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:20] range:NSMakeRange(0, string.length)];
[attrString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, string.length)];


mainTextView.attributedText = attrString;

知道是怎么回事吗？

140540 次浏览
小开

Attributed String Programming Guide:

UIFont *font = [UIFont fontWithName:@"Palatino-Roman" size:14.0];
NSDictionary *attrsDictionary = [NSDictionary dictionaryWithObject:font
forKey:NSFontAttributeName];
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:@"strigil" attributes:attrsDictionary];

Update: I tried to use addAttribute: method in my own app, but it seemed to be not working on the iOS 6 Simulator:

NSLog(@"%@", textView.attributedText);

The log seems to show correctly added attributes, but the view on iOS simulator was not display with attributes.

小开

There was a bug in iOS 6, that causes line height to be ignored when font is set. See answer to NSParagraphStyle line spacing ignored and longer bug analysis at Radar: UITextView Ignores Minimum/Maximum Line Height in Attributed String.

小开

I found your question because I was also fighting with NSAttributedString. For me, the beginEditing and endEditing methods did the trick, like stated in Changing an Attributed String. Apart from that, the lineSpacing is set with setLineSpacing on the paragraphStyle.

So you might want to try changing your code to:

NSString *string = @" Hello \n world";
attrString = [[NSMutableAttributedString alloc] initWithString:string];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy];


[paragraphStyle setLineSpacing:20]  // Or whatever (positive) value you like...
[attrSting beginEditing];


[attrString addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:20] range:NSMakeRange(0, string.length)];
[attrString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, string.length)];


[attrString endEditing];


mainTextView.attributedText = attrString;

Didn't test this exact code though, btw, but mine looks nearly the same.

EDIT:

Meanwhile, I've tested it, and, correct me if I'm wrong, the - beginEditing and - endEditing calls seem to be of quite an importance.

小开 
//For proper line spacing


NSString *text1 = @"Hello";
NSString *text2 = @"\nWorld";
UIFont *text1Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:10];
NSMutableAttributedString *attributedString1 =
[[NSMutableAttributedString alloc] initWithString:text1 attributes:@{ NSFontAttributeName : text1Font }];
NSMutableParagraphStyle *paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle1 setAlignment:NSTextAlignmentCenter];
[paragraphStyle1 setLineSpacing:4];
[attributedString1 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [attributedString1 length])];


UIFont *text2Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:16];
NSMutableAttributedString *attributedString2 =
[[NSMutableAttributedString alloc] initWithString:text2 attributes:@{NSFontAttributeName : text2Font }];
NSMutableParagraphStyle *paragraphStyle2 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle2 setLineSpacing:4];
[paragraphStyle2 setAlignment:NSTextAlignmentCenter];
[attributedString2 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle2 range:NSMakeRange(0, [attributedString2 length])];


[attributedString1 appendAttributedString:attributedString2];
小开

You can use this example and change it's implementation like this:

[self enumerateAttribute:NSParagraphStyleAttributeName
inRange:NSMakeRange(0, self.length)
options:0
usingBlock:^(id  _Nullable value, NSRange range, BOOL * _Nonnull stop) {
NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];


//add your specific settings for paragraph
//...
//...


[self removeAttribute:NSParagraphStyleAttributeName range:range];
[self addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:range];
}];

提交答案