我正在尝试在 UICollectionView 上实现捏合展开,但遇到了一些麻烦。与我能找到的所有示例代码不同,我这样做并不是作为交互式 UINavigationController 转换的一部分 - 我只需要就地展开一个项目。
这是我的捏合手势识别器:
- (void)pinchGestureDidPinch:(UIPinchGestureRecognizer *)recognizer
{
CGFloat targetScale = 3.0;
CGFloat scale = recognizer.scale;
if (recognizer.state == UIGestureRecognizerStateBegan) {
CGPoint point = [recognizer locationInView:self.collectionView];
NSIndexPath *rowUnder = [self.collectionView indexPathForItemAtPoint:point];
self.pinchingRow = [NSIndexPath indexPathForItem:0 inSection:rowUnder.section];
self.currentState = HACStreamViewControllerTransitioning;
self.expandedLayout.expandedSection = self.pinchingRow.section;
self.transitionLayout = [self.collectionView startInteractiveTransitionToCollectionViewLayout:self.expandedLayout completion:nil];
} else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {
if (scale >= targetScale) {
[self.collectionView finishInteractiveTransition];
self.currentState = HACStreamViewControllerExpanded;
} else {
[self.collectionView cancelInteractiveTransition];
self.currentState = HACStreamViewControllerCollapsed;
}
} else {
// change
CGFloat progress = MIN(targetScale / scale, 1.0);
progress = MAX(0.0, progress);
self.transitionLayout.transitionProgress = progress;
[self.transitionLayout invalidateLayout];
}
}
虽然调用 startInteractiveTransitionToCollectionViewLayout: 会导致异常:
0 ??? 0x0fcf577f 0x0 + 265246591,
1 UIKit 0x01e1f582 -[UICollectionViewTransitionLayout setTransitionProgress:] + 643,
2 UIKit 0x01d13053 -[UICollectionView _setCollectionViewLayout:animated:isInteractive:completion:] + 658,
3 UIKit 0x01d12be8 -[UICollectionView setCollectionViewLayout:] + 225,
4 UIKit 0x01d15e0a -[UICollectionView startInteractiveTransitionToCollectionViewLayout:completion:] + 821,
5 HAW Couples 0x0001beae -[HACStreamViewController pinchGestureDidPinch:] + 782,
6 UIKit 0x01a74f8c _UIGestureRecognizerSendActions + 230,
7 UIKit 0x01a73c00 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 383,
8 UIKit 0x01a7566d -[UIGestureRecognizer _delayedUpdateGesture] + 60,
9 UIKit 0x01a78bcd ___UIGestureRecognizerUpdate_block_invoke + 57,
10 UIKit 0x01a78b4e _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 317,
11 UIKit 0x01a6f248 _UIGestureRecognizerUpdate + 199,
12 UIKit 0x0173bd4a -[UIWindow _sendGesturesForEvent:] + 1291,
13 UIKit 0x0173cc6a -[UIWindow sendEvent:] + 1030,
14 UIKit 0x01710a36 -[UIApplication sendEvent:] + 242,
15 UIKit 0x016fad9f _UIApplicationHandleEventQueue + 11421,
16 CoreFoundation 0x033988af __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15,
17 CoreFoundation 0x0339823b __CFRunLoopDoSources0 + 235,
18 CoreFoundation 0x033b530e __CFRunLoopRun + 910,
19 CoreFoundation 0x033b4b33 CFRunLoopRunSpecific + 467,
20 CoreFoundation 0x033b494b CFRunLoopRunInMode + 123,
21 GraphicsServices 0x042619d7 GSEventRunModal + 192,
22 GraphicsServices 0x042617fe GSEventRun + 104,
23 UIKit 0x016fd94b UIApplicationMain + 1225,
24 HAW Couples 0x0000eefd main + 141,
25 libdyld.dylib 0x03bd5725 start + 0
异常消息:
*** setObjectForKey: object cannot be nil (key: actualAttribute)
我已经验证我的“目标”UICollectionViewLayout 是好的。以下替代方案(由点击触发)工作正常,并按预期进行动画处理:
[self.collectionView setCollectionViewLayout:self.expandedLayout animated:YES completion:^(BOOL finished) {
}];
最佳答案
我有完全相同的问题,就我而言,当布局之一是自定义布局而另一个布局是 UICollectionViewFlowLayout 时,会发生此崩溃。我仍在调查这个问题,但我想知道您是否有相同的设置。
编辑 1) 在我的自定义布局中,我有一个装饰 View ,我在 [UICollectionViewLayout layoutAttributesForElementsInRect:] 操作中为装饰 View 返回了 UICollectionViewLayoutAttributes。我在删除装饰 View 的布局属性后进行了测试,现在它可以完美运行。一种布局中的装饰 View 在另一种布局中不存在,这似乎是个问题,当我了解更多信息时,我会更新我的答案。
关于ios - UICollectionView 交互转换抛出异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19415030/