ios - UICollectionView 移动项目并保持单元格大小

Question

我有不同大小的单元格，我正在尝试移动 CollectionView 单元格，并保持移动/选定的单元格大小移动到新位置。

我做了 project在 Github 上公开，如果您想添加为合作者，请告诉我？

我正在对 UICollectionViewFlowLayout 进行子类化并实现了以下内容:

- (UICollectionViewLayoutInvalidationContext *)invalidationContextForInteractivelyMovingItems:(NSArray<NSIndexPath *> *)targetIndexPaths withTargetPosition:(CGPoint)targetPosition previousIndexPaths:(NSArray<NSIndexPath *> *)previousIndexPaths previousPosition:(CGPoint)previousPosition{

    UICollectionViewLayoutInvalidationContext *context = [super
                                                          invalidationContextForInteractivelyMovingItems:targetIndexPaths
                                                          withTargetPosition:targetPosition
                                                          previousIndexPaths:previousIndexPaths
                                                          previousPosition:previousPosition];

    [self.collectionView moveItemAtIndexPath:previousIndexPaths[0] toIndexPath:targetIndexPaths[0]];

    return context;
}

还尝试在 UICollectionViewController 中实现这一点:

-(NSIndexPath *)collectionView:(UICollectionView *)collectionView targetIndexPathForMoveFromItemAtIndexPath:(NSIndexPath *)originalIndexPath toProposedIndexPath:(NSIndexPath *)proposedIndexPath{
    if (originalIndexPath.section == proposedIndexPath.section) {
        return  proposedIndexPath;
    }else{
        return originalIndexPath;
    }
}

你知道如何保持尺寸吗？

Answer 1

我遇到了同样的问题，原因是你需要调用委托(delegate)的 moveItemAtIndexPath。

- (UICollectionViewLayoutInvalidationContext *)invalidationContextForInteractivelyMovingItems:(NSArray<NSIndexPath *> *)targetIndexPaths withTargetPosition:(CGPoint)targetPosition previousIndexPaths:(NSArray<NSIndexPath *> *)previousIndexPaths previousPosition:(CGPoint)previousPosition{

    UICollectionViewLayoutInvalidationContext *context = [super
                                                          invalidationContextForInteractivelyMovingItems:targetIndexPaths
                                                          withTargetPosition:targetPosition
                                                          previousIndexPaths:previousIndexPaths
                                                          previousPosition:previousPosition];

    [self.collectionView.dataSource collectionView:self.collectionView moveItemAtIndexPath:previousIndexPaths[0] toIndexPath:targetIndexPaths[0]];

    return context;
}