IOS入门-TargetAction

创建一个UIButton 并用Target - Action来监听它的点击事件

Target -- self控制器 

Action -- 具体动作，self控制器中的某个方法

forControlEvents:UIControlEventTouchUpInside -- 表示监听的事件

- (void)btnclick:(id)sender
{
    NSLog(@"点击%@" , [sender class]);
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = CGRectMake(100, 100, 100, 100);
    [btn setTitle:@"点击" forState:UIControlStateNormal];
    
    [btn addTarget:self action:@selector(btnclick:) forControlEvents:UIControlEventTouchUpInside];
    
    [self.view addSubview:btn];
}