有block回调的UIButton和Alert

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实现方式就是自定义一个继承于UIButton或者UIAlert的类,然后添加一个block的属性。

重写UIButton的初始化方法,

- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        [self addTarget:self action:@selector(onClick:) forControlEvents:UIControlEventTouchUpInside];    }    return self;}- (void)onClick:(id)sender{    _block(self);}

有block的alert,代码如下:

同样初始化init方法- (id)initWithTitle:(NSString *)title message:(NSString *)message cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString*)otherButtonTitles block:(TouchBlock)block{    self = [super initWithTitle:title message:message delegate:self cancelButtonTitle:cancelButtonTitle otherButtonTitles:otherButtonTitles, nil];//注意这里初始化父类的    if (self) {        self.block = block;    }    return self;}//#pragma mark -AlertViewDelegate- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{    //这里调用函数指针_block(要传进来的参数);    _block(buttonIndex);}

示例代码:

    BlockButton *button = [[BlockButton alloc]initWithFrame:CGRectMake(100, 100, 40, 20)];    [button setBlock:^(BlockButton *button){        AlertBlock *alert = [[AlertBlock alloc]initWithTitle:@"提示" message:nil cancelButtonTitle:@"取消" otherButtonTitles:@"确定" block:^(NSInteger buttonIndex){            //在这里面执行触发的行为,省掉了代理,这样的好处是在使用多个Alert的时候可以明确定义各自触发的行为,不需要在代理方法里判断是哪个Alert了            if (buttonIndex == 0) {                NSLog(@"取消");            }else if (buttonIndex == 1){                NSLog(@"确定");            }        }];        [alert show];    }];
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