手势检测

- (void)viewDidLoad
{
    [super viewDidLoad];
  // Do any additional setup after loading the view.
    UISwipeGestureRecognizer *recognizer;
    recognizer = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release];
}
-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer{
    if(recognizer.direction==UISwipeGestureRecognizerDirectionDown)
    {
        [self dismissViewControllerAnimated:YES completion:nil];
    }
}