ios - 当用户向下滑动两次触摸时如何防止 UITableView 中的 ScrollView ？

Question

我想要当用户在 UITableView 上向下滑动方向时，我做了一些事情并且表格没有滚动。我该怎么做？

Answer 1

如果您只是想让您的 UISwipeGestureRecognizer 与 UITableView 的 UIPanGestureRecognizer 一起触发，您只需设置滑动手势的委托(delegate)并实现

- (BOOL) gestureRecognizer:(UIGestureRecognizer *) gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *) otherGestureRecognizer

然后返回YES。

如果您想中断 tableview 的平移手势，您可能无法使用 UISwipeGestureRecognizer 来这样做，因为它在用户滑动一定距离后才会真正触发。

但是，如果需要，您可以使用 UIPanGestureRecognizer 来模拟该行为。我能够得到类似的东西:

#pragma mark UIViewController lifecycle

- (void) viewDidLoad
{
    [super viewDidLoad];

    UIPanGestureRecognizer *panner = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(didPan:)];
    [panner setDelegate:self];
    [panner setMinimumNumberOfTouches:2];
    [self.tableView addGestureRecognizer:panner];
}

#pragma mark custom swipe response

- (void) didSwipe
{
    NSLog(@"SWIPED!");
}

#pragma mark UIPanGestureRecognizer response

- (void) didPan:(UIPanGestureRecognizer *) recognizer
{
    [self cancelGestureRecognizer:self.tableView.panGestureRecognizer];

    if (recognizer.state == UIGestureRecognizerStateChanged)
    {
        CGPoint translation = [recognizer translationInView:self.view];

        if (translation.y > 20)
        {
            [self didSwipe];
            [self cancelGestureRecognizer:recognizer];
        }
    }
}

#pragma mark UIGestureRecognzierDelegate implementation
- (BOOL) gestureRecognizer:(UIGestureRecognizer *) gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *) otherGestureRecognizer
{
    //NOTE: blindly returning yes in this case is usually a bad idea. You should check the recognizers here. 
    return YES;
}

#pragma mark UIGestureRecognizer stuff that should be in a category and not this file.

- (void) cancelGestureRecognizer:(UIGestureRecognizer *) recognizer
{
    if (recognizer.enabled)
    {
        [recognizer setEnabled:NO];
        [recognizer setEnabled:YES];
    }
}

就是说，在大多数情况下，仅使用平移手势并根据平移的距离制作任何动画/过渡/交互(即 CGPoint 翻译)会带来更好的用户体验> 在这种情况下)。