Objective c 如何使用NSMutableAttributeString呈现多行UILabel

我正在尝试使用NSMutableAttributedString创建多行UILabel。 当我将一个属性指定给完整的字符串时，这样做很好：

UILabel *contentLabel = [[UILabel alloc] initWithFrame:CGRectMake(0,0,200,100)];
[contentLabel setLineBreakMode:NSLineBreakByWordWrapping];
[contentLabel setNumberOfLines:0];
[contentLabel setFont:[UIFont systemFontOfSize:13];

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"hello I am a long sentence that should break over multiple lines"];
[string addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:13] range:NSMakeRange(0, [string length])];

contentLabel.attributedText = string;

但我需要的是为NSAttributedString的不同子范围应用一些属性（对于某些粗体字）

我发现，如果我这样做，文本将不再呈现在标签中的多行上。它被渲染为一条直线，在标签的框架中垂直居中

---

这里缺少什么吗？

我经常使用UITextView，并以类似的方式为其分配一个文本属性：

        // creiamo textView descrizione
    UITextView *description = [[UITextView alloc] init];
    description.frame = CGRectMake(20, 453, 500, 190);

    NSDictionary *attribute1 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                     NSBackgroundColorAttributeName: [UIColor clearColor],
                                     NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Bold" size:22.0],
                                     };

    NSDictionary *attribute2 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                        NSBackgroundColorAttributeName: [UIColor clearColor],
                                        NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:10],
                                        };

    NSDictionary *attribute3 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                           NSBackgroundColorAttributeName: [UIColor clearColor],
                                           NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:14.0]
                                           };

    NSMutableAttributedString *info = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"%@ %@ %@ \n\n%@ \n     ", string1, string2 , string3, string4]];

    [info setAttributes:attribute1 range:NSMakeRange(0, ([string1 length]))];
    [info setAttributes:attribute2 range:NSMakeRange(([string1 length]),([string2 length]+[string3 length]))];
    [info setAttributes:attribute3 range:NSMakeRange(([string1 length] [string2 length]+[string3 length]), [string4 length])];

    description.attributedText = info;
    description.backgroundColor = [UIColor clearColor];
    description.editable = NO;
    description.textColor = [UIColor blackColor];
    [viewInfo addSubview:description];
    [description sizeToFit];

---

正如问题的注释中所讨论的，问题中提供的代码实际上工作正常，并且按照预期呈现属性字符串。（问题出在我代码的其他地方）

你把标签做得足够高，可以放第二行了吗？我无法在6.1上复制这个。我注意到您的代码有点不正确（setFont:行中缺少一个），您在一个地方使用了“label”而不是“contentLabel”）。你确定这是实际代码吗？@Kevin Ballard:是的，标签足够高。@KevinBallard:原来你是对的，我计算并分配给标签框架的所需高度不正确。谢谢你把我放在正确的轨道上。你可能应该写下你最后的评论作为一个答案，并接受它，这样其他用户（像我一样）会立即看到它。

        // creiamo textView descrizione
    UITextView *description = [[UITextView alloc] init];
    description.frame = CGRectMake(20, 453, 500, 190);

    NSDictionary *attribute1 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                     NSBackgroundColorAttributeName: [UIColor clearColor],
                                     NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Bold" size:22.0],
                                     };

    NSDictionary *attribute2 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                        NSBackgroundColorAttributeName: [UIColor clearColor],
                                        NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:10],
                                        };

    NSDictionary *attribute3 = @{NSForegroundColorAttributeName: [UIColor blackColor],
                                           NSBackgroundColorAttributeName: [UIColor clearColor],
                                           NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue" size:14.0]
                                           };

    NSMutableAttributedString *info = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"%@ %@ %@ \n\n%@ \n     ", string1, string2 , string3, string4]];

    [info setAttributes:attribute1 range:NSMakeRange(0, ([string1 length]))];
    [info setAttributes:attribute2 range:NSMakeRange(([string1 length]),([string2 length]+[string3 length]))];
    [info setAttributes:attribute3 range:NSMakeRange(([string1 length] [string2 length]+[string3 length]), [string4 length])];

    description.attributedText = info;
    description.backgroundColor = [UIColor clearColor];
    description.editable = NO;
    description.textColor = [UIColor blackColor];
    [viewInfo addSubview:description];
    [description sizeToFit];