Button.titleLabel.lineBreakMode = NSLineBreakByTruncatingTail;//  设置尾部省略

 

typedef NS_ENUM(NSInteger, NSLineBreakMode) {
    NSLineBreakByWordWrapping = 0,         // Wrap at word boundaries, default    默认情况下，在单词边界处换行
    NSLineBreakByCharWrapping,        // Wrap at character boundaries     在字符边界处换行
    NSLineBreakByClipping,        // Simply clip    简单的剪辑
    NSLineBreakByTruncatingHead,    // Truncate at head of line: "...wxyz"  在前面
    NSLineBreakByTruncatingTail,    // Truncate at tail of line: "abcd..."   在后面
    NSLineBreakByTruncatingMiddle    // Truncate middle of line:  "ab...yz"  在中间
} NS_ENUM_AVAILABLE(10_0, 6_0);