UIButton图片位置设置

作为一名已经100天的ios小菜， 我也决定开始学习写点东西了。刚刚需要设置UIbuttom的图片位置，stackoverflow了一番，找到了这个：ios - iPhone UIButton - image position - Stack Overflow

里面投票最高的是

button.titleEdgeInsets = UIEdgeInsetsMake(0, -button.imageView.frame.size.width, 0, button.imageView.frame.size.width);

button.imageEdgeInsets = UIEdgeInsetsMake(0, button.titleLabel.frame.size.width, 0, -button.titleLabel.frame.size.width);

我更希望能直接在storyboard中直接设置图片上下左右的位置，于是乎来吧，扩展UIButton, 利用kvc 直接设置：

```

extension UIButton {

func setImageUp(state:Bool){

     if(self.imageView == nil || self.titleLabel == nil || state == false){ return }

        self.sizeToFit()

        let titleXOffset = self.imageView!.frame.width/2

        let titleYOffset = self.imageView!.frame.height/2

        self.titleEdgeInsets = UIEdgeInsetsMake(titleYOffset, -titleXOffset, -titleYOffset, titleXOffset)

        let imageXoffset = self.titleLabel!.frame.width/2

        let imageYoffset = self.titleLabel!.frame.height/2

        self.imageEdgeInsets = UIEdgeInsetsMake(-imageYoffset, imageXoffset, imageYoffset, -imageXoffset)

}

func setImageBottom(state:Bool){

    if(self.imageView == nil || self.titleLabel == nil || state == false){ return }

       self.sizeToFit()

        let titleXOffset = self.imageView!.frame.width/2

        let titleYOffset = self.imageView!.frame.height/2

        self.titleEdgeInsets = UIEdgeInsetsMake(-titleYOffset, -titleXOffset, titleYOffset, titleXOffset)

        let imageXoffset = self.titleLabel!.frame.width/2

        let imageYoffset = self.titleLabel!.frame.height/2

        self.imageEdgeInsets = UIEdgeInsetsMake(imageYoffset, imageXoffset, -imageYoffset, -imageXoffset)

}

func setImageRight(state:Bool){

    if(self.imageView == nil || self.titleLabel == nil || state == false){ return }

    self.sizeToFit()

    self.titleEdgeInsets = UIEdgeInsetsMake(0, -self.imageView!.frame.size.width, 0, self.imageView!.frame.size.width)

    self.imageEdgeInsets = UIEdgeInsetsMake(0, self.titleLabel!.frame.size.width, 0, -self.titleLabel!.frame.size.width)

}

}

ok,现在直接在storyboard中的user defined runtime attributes中设置就行了

结果

有不对的地方，欢迎大神指正。。。