iOS 用for循环写了一排button

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

    float x = 20;

    float y = 100;

    float w = 30;

    float h = 30;

    

    for (int i = 0; i<5; i++) {

        UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];

        [btn setFrame:CGRectMake(w*i+x, y, w, h)];

        btn.backgroundColor = [UIColor redColor];

        [btn setTitle:[NSString stringWithFormat:@"%d",i] forState:UIControlStateNormal];

        [btn addTarget:self action:@selector(btn_click:) forControlEvents:UIControlEventTouchUpInside];

        [self.view addSubview:btn];

    }

}

- (void)btn_click:(id)sender

{

    UIButton *btn = sender;

    btn.backgroundColor = [UIColor greenColor];

}

是这个意思么。点了变颜色了。