修改UIButton图片和文字的位置

　　　　　　　　　[self.shixiangBtn.imageView setContentMode:UIViewContentModeScaleAspectFit];
                
                // 交换button中title和image的位置
                CGFloat labelWidth = self.shixiangBtn.titleLabel.frame.size.width;
                CGFloat imageWith = self.shixiangBtn.imageView.frame.size.width;
                self.shixiangBtn.imageEdgeInsets = UIEdgeInsetsMake(0, labelWidth, 0, -labelWidth);
                self.shixiangBtn.titleEdgeInsets = UIEdgeInsetsMake(0, -imageWith, 0, imageWith);