iOS开发 ☞ UILable详解

一、Label常见属性
1、设置截断模式

typedef NS_ENUM(NSInteger, NSLineBreakMode) {
    NSLineBreakByWordWrapping = 0,      // Wrap at word boundaries, default
    NSLineBreakByCharWrapping,      // Wrap at character boundaries
    NSLineBreakByClipping,      // Simply clip
    NSLineBreakByTruncatingHead,    // Truncate at head of line: "...wxyz" NSLineBreakByTruncatingTail, // Truncate at tail of line: "abcd..." NSLineBreakByTruncatingMiddle // Truncate middle of line: "ab...yz" }

2、设置为高亮状态及高亮状态的颜色
highlighted
highlightedTextColor

二、内容自适应Label宽度
minimumScaleFactor
设置最小收缩比例，如果Label宽度小于文字长度时，文字
进行收缩，收缩超过比例后，停止收缩。
adjustsFontSizeToFitWidth
设置字体大小适应label宽度
如果只设置adjustsFontSizeToFitWidth内容会无限小，如果设置最小收缩比例，内容不会无限缩小，超出的部分显示省略号。

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
    label.text = @"magicmagicmagicmagicmaigcmagicmagicmagicmagicmaig";
    label.backgroundColor = [UIColor purpleColor];
    label.adjustsFontSizeToFitWidth = YES;
    [self.view addSubview:label];

在实际应用中上面的效果显然是不行的，添加一行代码：

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
    label.minimumScaleFactor = .5f;
    label.text = @"magicmagicmagicmagicmaigcmagicmagicmagicmagicmaig";
    label.backgroundColor = [UIColor purpleColor];
    //中间截断
    label.lineBreakMode = NSLineBreakByTruncatingMiddle;
    label.adjustsFontSizeToFitWidth = YES;
    [self.view addSubview:label];

三、Label**高度**自适应内容
numberOfLines
设置label显示的行数，为0表示不限制行数
siziToFit
calls sizeThatFits: with current view bounds and changes bounds size.
这个方法会调用sizeThatFits,用当前的bounds改变原有的bounds

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 100)];
    view.backgroundColor = [UIColor orangeColor];
    [self.view addSubview:view];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 200, 100)];
    label.text = @"magicmagicsdjflalsdjfljlasjdlfasmagicmagicmaigcmagicmagicmagicmagicmaig";
    label.backgroundColor = [UIColor greenColor];
    label.numberOfLines = 0;
    [label sizeToFit];
    [self.view addSubview:label];

效果如下: