垂直滚动视野内的水平盘

Question

我有一个滚动视图，仅限于垂直滚动。在它的内部，我希望有一个UIPanGestureRecognizer的视图，只识别水平平底锅。

同样，水平识别器赢了，并防止滚动视图滚动。

我希望水平平底锅，如果它检测到一个主要的水平姿态，否则垂直滚动将获胜。非常类似于邮箱的工作方式，或在iOS8 Mail.app中滑动

Answer 1

您可以使用UIGestureRecognizerDelegate方法之一(如gestureRecognizerShouldBegin: )来指定在哪种情况下触发pan手势。

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {

    // If the gesture is a pan, determine whether it starts out more
    // horizontal than vertical than act accordingly
    if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {

        UIPanGestureRecognizer *panGestureRecognizer = (UIPanGestureRecognizer *)gestureRecognizer;
        CGPoint velocity = [panGestureRecognizer velocityInView:self.view];

        if (gestureRecognizer == self.scrollView.panGestureRecognizer) {
            // For the vertical scrollview, if it's more vertical than
            // horizontal, return true; else false
            return fabs(velocity.y) > fabs(velocity.x);
        } else {
            // For the horizontal pan view, if it's more horizontal than
            // vertical, return true; else false
            return fabs(velocity.y) < fabs(velocity.x);
        }
    }
    else
        return YES;
}