addTarget可以为button添加监听方法：

示例代码为：

   

        //实例化一个button
        UIButton *button =  [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 20, 30)];
        //为button设置背景颜色
        [button setBackgroundColor:[UIColor redColor]];
         
         //添加监听方法
         [button addTarget:self
                    action:@selector(clickButton)
          forControlEvents:UIControlEventTouchUpInside];
         
         //添加button
         [self addSubview:button];

-(void)clickButton{
    
    NSLog(@"按钮被点击了");
    
}