手势的状态判断，

//弹出拍照 sheet

- (IBAction)chooseImage:(id)sender

{

    UIGestureRecognizer* recognizer = (UIGestureRecognizer*)sender;

    NSLog(@"%d", recognizer.state);

    if (recognizer.state == UIGestureRecognizerStateBegan) {

        UIActionSheet* actionSheet = [[UIActionSheetalloc] initWithTitle:@"设置封面" delegate:selfcancelButtonTitle:@"取消"destructiveButtonTitle:nilotherButtonTitles:@"拍照", @"相册", nil];

        actionSheet.tag = SETBGCOVER;

        [actionSheet showInView:SharedAppDelegate.window];

    }

}

如果不判断，会调用两次的，