我有一个UICollectionView实现自定义UICollectionViewCells的基于网格的布局.为了允许单元格响应拖动,我单独向每个单元格添加UIPanGestureRecognizer.
当我触摸时,UICollectionView仍然(水平地)滚动并从单元格之间的点开始向左/向右滑动,但只要将平移手势识别器添加到单元格中,当我开始轻扫时,似乎CollectionView拒绝滚动在一个细胞内.
现在,我将水平左/右拖动与垂直向上/向下拖动分开,因此拖出单元格(垂直滑动)和滚动CollectionView(水平滑动)之间不应存在任何冲突.在这种情况下,如何将滑动传递到集合/滚动视图,以便它知道像正常一样滚动?不得不开始在细胞之间的边界或间隔是非常烦人的.
一旦我从单元格中移除平移手势,无论我是开始在单元格上还是在单元格之间滑动,滚动都会正常工作.
编辑:下面作为当前代码发布的所需平移手势行为
// Handle pans by detecting swipes: -(void) handlePan:(UIPanGestureRecognizer*)recognizer { // Calculate touch location CGPoint touchXY = [recognizer locationInView:masterWindowView]; // Handle touch if (recognizer.state == UIGestureRecognizerStateBegan) { gestureWasHandled = NO; pointCount = 1; startPoint = touchXY; } if (recognizer.state == UIGestureRecognizerStateChanged) { ++pointCount; // Calculate whether a swipe has occurred float dX = deltaX(touchXY,startPoint); float dY = deltaY(touchXY,startPoint); BOOL finished = YES; if ((dX > kSwipeDragMin) && (ABS(dY) < kDragLimitMax)) { touchType = TouchSwipeLeft; NSLog(@"LEFT swipe detected"); [recognizer requireGestureRecognizerToFail:recognizer]; //[masterScrollView handlePan] } else if ((dX < -kSwipeDragMin) && (ABS(dY) < kDragLimitMax)) { touchType = TouchSwipeRight; NSLog(@"RIGHT swipe detected"); [recognizer requireGestureRecognizerToFail:recognizer]; } else if ((dY > kSwipeDragMin) && (ABS(dX) < kDragLimitMax)) { touchType = TouchSwipeUp; NSLog(@"UP swipe detected"); } else if ((dY < -kSwipeDragMin) && (ABS(dX) < kDragLimitMax)) { touchType = TouchSwipeDown; NSLog(@"DOWN swipe detected"); } else finished = NO; // If unhandled and downward,produce a new draggable view if (!gestureWasHandled && finished && (touchType == TouchSwipeDown)) { [self.delegate cellBeingDragged:self]; dragView.center = touchXY; dragView.hidden = NO; dragView.backgroundColor = [UIColor clearColor]; masterScrollView.scrollEnabled = NO; // prevent user from scrolling during gestureWasHandled = YES; } else if (gestureWasHandled) { // allow continued dragging after detection dragView.center = touchXY; } } if (recognizer.state == UIGestureRecognizerStateEnded) { // ensure that scroll view returns to scrollable if (gestureWasHandled) { [self.delegate cell:self dragEndedAt:touchXY]; } } } // Allow simultaneous recognition -(BOOL) gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer*)otherGestureRecognizer { return YES; }
该代码适用于每个单独的单元格.当连接到UICollectionView作为其手势识别器时它不起作用,并且它实际上停止所有滚动.
解决方法
而不是将UIPanGestureRecognizer附加到每个单元格(这会降低性能),而是将UIPanGestureRecognizer添加到UICollectionView,当发生平移手势时,使用
locationInView
获取平移开始的UICollectionView中的点,然后是
indexPathForItemAtPoint
,它将返回索引路径对于你应该动画的单元格.
这样,您将只有一个手势识别器(好!)用于整个集合视图,同时还在视图控制器中保持控制(如您所愿) – 双赢!
使用此解决方案,在视图控制器中,您将实现gestureRecognizer:shouldReceiveTouch:,获取给定的gestureRecognizer,确保它是您的UIPanGestureRecognizer并使用其translationInView:方法来确定转换是在X轴还是Y轴上.使用该信息来决定是否要返回YES或NO.例如:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceivetouch:(UITouch *)touch { if([gestureRecognizer isEqual:myTapGesture]) { CGPoint point = [gestureRecognizer translationInView:self.collectionView]; if(point.x != 0) { //adjust this condition if you want some leniency on the X axis //The translation was on the X axis,i.e. right/left,//so this gesture recognizer shouldn't do anything about it return NO; } } return YES; }