关于UIButton的 setBackgroundImage 和 setImage区别

关于UIButton的 setBackgroundImage 和 setImage区别

相同点就是两者都可以设置图片。区别如下：
1，setBackgroundImage，图片会随着按钮的大小而改变，图片自动会拉伸来适应按钮的大小，这个时候任然可以设置按钮的title，图片不会挡住title；
2，setImage，此时再设置title，title将无法显示。图片不会随着按钮的大小改变而改变。

代码说明下，使用的图片的大小是70＊27：

UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
   [btn2 setBackgroundImage:[UIImage imageNamed:@"sign.png"] forState:UIControlStateNormal];
    [btn2 setTitle:@"AAA" forState:UIControlStateNormal];
    btn2.frame = CGRectMake( 10 , 200, 75, 27 );
    [self.view addSubview:btn2 ];

采用setImage：
UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
 [btn2 setImage:[UIImage imageNamed:@"sign.png"] forState:UIControlStateNormal];
 [btn2 setTitle:@"AAA" forState:UIControlStateNormal];
 btn2.frame = CGRectMake( 10 , 200, 75, 27 );
 [self.view addSubview:btn2 ];```

![setImage的看不到AAA的title](http://img.blog.csdn.net/20150710142744237)

把按钮的大小改变，代码如下：

UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
[btn2 setBackgroundImage:[UIImage imageNamed:@”sign.png”] forState:UIControlStateNormal];
[btn2 setTitle:@”AAA” forState:UIControlStateNormal];
btn2.frame = CGRectMake( 10 , 200, 175, 27 );
[self.view addSubview:btn2 ];

效果如下

采用setImage，代码如下

UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
[btn2 setImage:[UIImage imageNamed:@”sign.png”] forState:UIControlStateNormal];
[btn2 setTitle:@”AAA” forState:UIControlStateNormal];
btn2.frame = CGRectMake( 10 , 200, 175, 27 );
[self.view addSubview:btn2 ];
“`

效果如下：