Swift button 设置图片位置

在开发过程中经常遇到 按钮 与图标的放置问题，有时按钮中图片与文字的位置需要我们设置。

一种方法是我们根据具体情况利用titleEdgeInsets、imageEdgeInsets这两个属性来设置具体的位置，另一种是我们直接封装一个imageView和label 来在定义button。两种方法都可以，在Swift中使用扩展 UIButton 来设置 titleEdgeInsets、imageEdgeInsets 感觉更灵活更方便一些。

直接上代码：

enum ButtonEdgeInsetsStyle {
   case ButtonEdgeInsetsStyleTop // image在上，label在下
   case ButtonEdgeInsetsStyleLeft  // image在左，label在右
   case ButtonEdgeInsetsStyleBottom  // image在下，label在上
   case ButtonEdgeInsetsStyleRight // image在右，label在左
}

extension UIButton {
    func layoutButtonEdgeInsets(style:ButtonEdgeInsetsStyle,space:CGFloat) {
      var labelWidth : CGFloat = 0.0
      var labelHeight : CGFloat = 0.0
      var imageEdgeInset = UIEdgeInsetsZero
      var labelEdgeInset = UIEdgeInsetsZero
      let imageWith = self.imageView?.frame.size.width
      let imageHeight = self.imageView?.frame.size.height
      if Double(UIDevice.currentDevice().systemVersion) >= 8.0 {
           labelWidth = (self.titleLabel?.intrinsicContentSize().width)!
           labelHeight = (self.titleLabel?.intrinsicContentSize().height)!
      }else {
          labelWidth = (self.titleLabel?.frame.size.width)!
          labelHeight = (self.titleLabel?.frame.size.height)!
      }
      labelWidth = CGFloat(36)
      switch style {
      case .ButtonEdgeInsetsStyleTop:
          imageEdgeInset = UIEdgeInsetsMake(-labelHeight-space/2.0, 0, 0, -labelWidth)
          labelEdgeInset = UIEdgeInsetsMake(0, -imageWith!, -imageHeight!-space/2.0, 0)
      case .ButtonEdgeInsetsStyleLeft:
        imageEdgeInset = UIEdgeInsetsMake(0, -space/2.0, 0, space/2.0);
        labelEdgeInset = UIEdgeInsetsMake(0, space/2.0, 0, -space/2.0);
      case .ButtonEdgeInsetsStyleBottom:
          imageEdgeInset = UIEdgeInsetsMake(0, 0, -labelHeight-space/2.0, -labelWidth)
          labelEdgeInset = UIEdgeInsetsMake(-imageHeight!-space/2.0, -imageWith!, 0, 0)
      case .ButtonEdgeInsetsStyleRight:
          // To Do print("坐标是====\(labelWidth)=====\(space)")
          imageEdgeInset = UIEdgeInsetsMake(0, labelWidth+space/2.0, 0, -labelWidth-space/2.0)
          labelEdgeInset = UIEdgeInsetsMake(0, -imageWith!-space/2.0, 0, imageWith!+space/2.0)
      }
      self.titleEdgeInsets = labelEdgeInset
      self.imageEdgeInsets = imageEdgeInset
  }
}

如代码所示，我们通过枚举，来列出图片与文字可能出现的位置，这样就能在方法中根据具体情况来展示文字与图片的位置。至于第二种方法我们可以通过xib或者纯代码封装一个button，在这里就不介绍了。