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;
}
