UIButton自定义图文位置，上图下文

QQ20170817-0.png

之前遇到上图下文、下图上文的item，都是用UIImageView + Label的方式解决，过于麻烦。一直想通过设置button的图文位置来实现这种需求，但是无奈EdgeInsets总是设置不对，每次使用每次去算。某次在github上看到一个demo受到了启发，经我使用过程中改良后，现在只需要设置DirectionButton的图片方位、图片和文字的间距，即能随心所欲实现button的图文位置，即便文字宽度大于图片宽度，也能居中显示，实现需求。

//按钮中图片的位置
public enum ImageAlignment: Int {
    //  默认图片在上
    case top = 0
    case left = 1
    case bottom = 2
    case right = 3
}

class DirectionButton: UIButton {
    var imageAlignment: ImageAlignment = .top //默认上图下文
    var spaceBetweenTitleAndImage: CGFloat = 10
    override func layoutSubviews() {
        super.layoutSubviews()
        let space = self.spaceBetweenTitleAndImage
        let titleW = self.titleLabel?.bounds.size.width
        let titleH = self.titleLabel?.bounds.size.height
        let imageW = self.imageView?.bounds.size.width
        let imageH = self.imageView?.bounds.size.height
        
        let btnCenterX = self.bounds.size.width / 2 //按钮中心点X的坐标（以按钮左上角为原点的坐标系）
        let imageCenterX = btnCenterX - titleW!/2; //imageView中心点X的坐标（以按钮左上角为原点的坐标系）
        //let titleCenterX = btnCenterX + imageW!/2;//titleLabel中心点X的坐标（以按钮左上角为原点的坐标系）
        
        switch imageAlignment {
        case .top:
            self.titleEdgeInsets = UIEdgeInsetsMake(imageH!/2 + space/2, -imageW!, -(imageH!/2 + space/2), 0)
            self.imageEdgeInsets = UIEdgeInsetsMake(-(titleH!/2 + space/2), btnCenterX - imageCenterX, titleH!/2 + space/2, -(btnCenterX - imageCenterX))
            self.imageView?.center.x = (self.titleLabel?.center.x)!
            self.titleLabel?.textAlignment = .center
            
        case .left:
            self.titleEdgeInsets = UIEdgeInsetsMake(0, space/2, 0,  -(space/2))
            self.imageEdgeInsets = UIEdgeInsetsMake(0, -(space/2), 0, space/2)
            
        case .bottom:
            self.titleEdgeInsets = UIEdgeInsetsMake(-(imageH!/2 + space/2), -imageW!, imageH!/2 + space/2, 0)
            self.imageEdgeInsets = UIEdgeInsetsMake(titleH!/2 + space/2, btnCenterX - imageCenterX,-(titleH!/2 + space/2), -(btnCenterX - imageCenterX))
            self.imageView?.center.x = (self.titleLabel?.center.x)!
            self.titleLabel?.textAlignment = .center
            
        case .right:
            self.titleEdgeInsets = UIEdgeInsetsMake(0, -(imageW! + space/2), 0, imageW! + space/2)
            self.imageEdgeInsets = UIEdgeInsetsMake(0, titleW! + space/2, 0, -(titleW! + space/2))
        }
    }
}

使用方式，其他设置与UIButton无异

let testButton = DirectionButton()
testButton.imageAlignment = .top //上图下文
testButton.spaceBetweenTitleAndImage = 3 //图片与文字之间的间距