FormSheet式模态视图，点击模态视图外隐藏模态视图的方法

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    _tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(handleTapBehind:)];
    [_tapRecognizer setNumberOfTapsRequired:1];
    _tapRecognizer.cancelsTouchesInView = NO; 
    [self.view.window addGestureRecognizer:_tapRecognizer];
    [_tapRecognizer setDelegate:(id<UIGestureRecognizerDelegate>)self];
}

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

    if (sender.state == UIGestureRecognizerStateEnded) {
     
        CGPoint location = [sender locationInView:nil];      

        if (UIDevice currentDevice]systemVersion] floatValue] < 8.0) {

            if (UIInterfaceOrientationIsLandscape([UIApplicationsharedApplication].statusBarOrientation)) {

                location = CGPointMake(location.y, location.x);
            }
        }       

        if (![self.view pointInside:[self.view convertPoint:location fromView:self.view.window] withEvent:nil]) {
        
            [self.view.window removeGestureRecognizer:sender];
            [self dismissViewControllerAnimated:YES completion:nil];
        }
    }
}

#pragma mark - UIGestureRecognizer Delegate

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    return YES;
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer*)otherGestureRecognizer
{
    return YES;
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    return YES;
}