1、應用場景，文字居左，圖片居中

 //設置圖片間距，使其居右對齊
btn.imageEdgeInsets = UIEdgeInsetsMake(0,btn.size.width - 12 - btn.imageView.image.size.width, 0, 0);
//文字居左對齊
 btn.titleEdgeInsets = UIEdgeInsetsMake(0, -(btn.imageView.image.size.width), 0, 0);
//設置文字居左且中心對齊
 [btn setContentHorizontalAlignment:UIControlContentHorizontalAlignmentLeft];
 [btn setContentVerticalAlignment:UIControlContentVerticalAlignmentCenter];

UIKit學習之UIButton篇