ios - 如何使用 UISwipeGestureRecognizer 检测 UITableViewCell 中的滑动事件

Question

我有一个 UITableViewCell 类，我想在其中检测滑动事件(删除)，以隐藏在 drawRect 中绘制的一些图形

首先，我向单元格添加了一个UISwipeGestureRecognice:

// Init swipe gesture recognizer
self.swipeRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeCell:)];
self.swipeRecognizer.direction = UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight;
self.swipeRecognizer.delegate = self;
[self.contentView addGestureRecognizer:self.swipeRecognizer];

然后我实现了一种对滑动事件使用react的方法:

- (void)swipeCell:(UISwipeGestureRecognizer *)recognizer
{
    switch (recognizer.state) {
        case UIGestureRecognizerStateBegan:
            self.swipeStartPoint = [recognizer locationInView:self.backgroundView];
            BaseLogDebug(INFO, @"Swipe Began at %@", NSStringFromCGPoint(self.swipeStartPoint));
            break;
        case UIGestureRecognizerStateChanged: {
            CGPoint currentPoint = [recognizer locationInView:self.backgroundView];
            CGFloat deltaX = currentPoint.x - self.swipeStartPoint.x;
            BaseLogDebug(INFO, @"Swipe Moved %f", deltaX);
        }
            break;
        case UIGestureRecognizerStateEnded:
            BaseLogDebug(INFO, @"Swipe Ended");
            break;
        case UIGestureRecognizerStateCancelled:
            BaseLogDebug(INFO, @"Swipe Cancelled");
            break;
        default:
            break;
    }
}

为了允许同步手势识别器，我实现了以下方法:

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

手势识别唯一能识别的状态是 UIGestureRecognizerStateEnded 状态。我的代码有什么问题吗？

Answer 1

来自UIGestureRecognizer Class Reference docs :

从 UIGestureRecognizerStatePossible 到 UIGestureRecognizerStateFailed 或 UIGestureRecognizerStateRecognized 的离散手势转换的识别器。

和

手势识别器识别离散事件，例如点击或滑动，但不报告手势内的变化。换句话说，离散手势不会通过 Began 和 Changed 状态转换，它们不会失败或被取消。

UISwipeGestureRecognizer 是一种离散手势。如果您想要连续(但相似)的手势，请改用 UIPanGestureRecognizer。