为button添加多个相同的controlEvent会怎样?

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    button.frame = self.view.bounds;
    [button addTarget:self action:@selector(aaa) forControlEvents:UIControlEventTouchUpInside];
    [button addTarget:self action:@selector(bbb) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}

- (void)aaa{
    NSLog(@"aaa");
    
}

- (void)bbb {
    NSLog(@"bbb");
}

结果就是两个都会运行 输出:

2017-09-12 19:09:15.288240+0800 pinglun[18874:4238746] aaa
2017-09-12 19:09:15.288443+0800 pinglun[18874:4238746] bbb

可以使用removeTarget方法移除

[button removeTarget:self action:nil forControlEvents:UIControlEventTouchUpInside];