我们经常会循环创建button，很多时候我们需要根据文字的长度来创建不同宽度的button。下面我们开始创建：

1.创建button：

func createButton() {
        //dataSource是我的数据源
        for i in 0..<dataSource!.count {
            let button = UIButton(type: .Custom)
            button.backgroundColor = YYMain_Color
            button.layer.cornerRadius = 8.0
            button.layer.masksToBounds = true

            view.addSubview(button)
        }
}

2.获取文字的长度：

  //创建属性
  let attributes = [NSForegroundColorAttributeName: UIColor.whiteColor(), NSFontAttributeName: UIFont.systemFontOfSize(14)]
  //将String转换成NSString
  let keyword: NSString = NSString(CString: dataSource![i].keyword!.cStringUsingEncoding(NSUTF8StringEncoding)!, encoding: NSUTF8StringEncoding)!
  //获取文字的长度
  let length = keyword.boundingRectWithSize(CGSizeMake(SCREEN_WIDTH, 2000), options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: attributes, context: nil).size.width

3.把attribute给button：

  //为button赋值
  let attributeString = NSAttributedString(string: dataSource![i].keyword!, attributes: attributes)
  button.setAttributedTitle(attributeString, forState: .Normal)

4.设置button的大小：

  //先定义两个变量
  var w: CGFloat = 0
  var h: CGFloat = 90
  //设置button的frame
  button.frame = CGRectMake(10 + w, h, length + 15, 30)
  //当button的位置超出右侧边缘时换行
  if 10+w+length+15 > SCREEN_WIDTH {
          w = 0
          h = h + button.frame.size.height + 10
          button.frame = CGRectMake(10+w, h, length+15, 30)
    }
    w = button.frame.size.width + button.frame.origin.x

OK👌效果如下：

循环创建button.png

最终代码：

var w: CGFloat = 0
var h: CGFloat = 90
 func createButton() {

        for i in 0..<dataSource!.count {
            let button = UIButton(type: .Custom)
            button.backgroundColor = YYMain_Color
            button.layer.cornerRadius = 8.0
            button.layer.masksToBounds = true
            
            let attributes = [NSForegroundColorAttributeName: UIColor.whiteColor(), NSFontAttributeName: UIFont.systemFontOfSize(14)]
            let keyword: NSString = NSString(CString: dataSource![i].keyword!.cStringUsingEncoding(NSUTF8StringEncoding)!, encoding: NSUTF8StringEncoding)!
            let length = keyword.boundingRectWithSize(CGSizeMake(SCREEN_WIDTH, 2000), options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: attributes, context: nil).size.width
            //为button赋值
            let attributeString = NSAttributedString(string: dataSource![i].keyword!, attributes: attributes)
            button.setAttributedTitle(attributeString, forState: .Normal)
            //设置button的frame
            button.frame = CGRectMake(10 + w, h, length + 15, 30)
            //当button的位置超出右侧边缘时换行
            if 10+w+length+15 > SCREEN_WIDTH {
                w = 0
                h = h + button.frame.size.height + 10
                button.frame = CGRectMake(10+w, h, length+15, 30)
            }
            w = button.frame.size.width + button.frame.origin.x
            view.addSubview(button)
        }
}