UILabel显示固定行数的问题

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在项目中我们有时会遇到这样的需求：显示一段文字，但这段文字最多显示4行。

我们首先考虑没有行数显示的情况：

UILabel * lbl = [UILabel alloc init];

    lbl.backgroundColor = UIColor redColor;

    lbl.textColor = UIColor blackColor;

    lbl.numberOfLines = 0;

    lbl.text = @"连卡精神分裂就离开家啊";

    lbl.lineBreakMode = UILineBreakModeWordWrap;

NSMutableDictionary * dic = NSMutableDictionary dictionary;

    dicNSFontAttributeName = UIFont systemFontOfSize:17;

CGRect rect = lbl.text boundingRectWithSize:CGSizeMake(100, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil;

NSLog(@"%f-----%f", rect.size.width, rect.size.height);

    lbl.frame = (CGRect){{0, 20}, rect.size};

    self.view addSubview:lbl;

这样单元格高度会进行自适应。

如果显示固定行数，我们需要知道固定行数时单元格的高度

UILabel * lbl = [UILabel alloc init];

    lbl.backgroundColor = UIColor redColor;

    lbl.textColor = UIColor blackColor;

    lbl.numberOfLines = 0;

    lbl.text = @"连卡精神分裂就离开家啊";

    lbl.lineBreakMode = UILineBreakModeWordWrap;

NSMutableDictionary * dic = NSMutableDictionary dictionary;

    dicNSFontAttributeName = UIFont systemFontOfSize:17;

CGRect rect = lbl.text boundingRectWithSize:CGSizeMake(100, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil;

NSLog(@"%f-----%f", rect.size.width, rect.size.height);

    lbl.frame = (CGRect){{0, 20}, rect.size};

if (rect.size.height > 102) {

        lbl.numberOfLines = 5;

        lbl.frame = (CGRect){{0, 20}, {100, 101.435547}};

    }

    self.view addSubview:lbl;