iOS巅峰之点击UIAlertView的灰色部分也能dismiss消失

{

    UIAlertView *alert;

    UITapGestureRecognizer *recognizerTap;

}

- (void)viewDidLoad {

    [super viewDidLoad];

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

    UIButton *button = [UIButton buttonWithType:(UIButtonTypeCustom)];

    button.frame = CGRectMake(100, 100, 100, 100);

    [button addTarget:self action:@selector(actionButton) forControlEvents:(UIControlEventTouchUpInside)];

    button.backgroundColor = [UIColor redColor];

    [self.view addSubview:button];

}

- (void)actionButton

{

    alert = [[UIAlertView alloc] initWithTitle:@"模态测试"

                                       message:@"请点击四周的模态区域我就消失"

                                      delegate:nil

                             cancelButtonTitle:@"确定"

                             otherButtonTitles:nil];

    [alert show];

    recognizerTap = [[UITapGestureRecognizer alloc] initWithTarget:self

                                                            action:@selector(handleTapBehind:)];

    [recognizerTap setNumberOfTapsRequired:1];

    recognizerTap.cancelsTouchesInView = NO;

    [alert.window addGestureRecognizer:recognizerTap];

}

- (void)handleTapBehind:(UITapGestureRecognizer *)sender{

    if (sender.state == UIGestureRecognizerStateEnded) {

        CGPoint location = [sender locationInView:nil];

        if (![alert pointInside:[alert convertPoint:location fromView:alert.window] withEvent:nil]) {

            [alert.window removeGestureRecognizer:sender];

            [alert dismissWithClickedButtonIndex:0 animated:YES];

        }  

    }  

}