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。

我已经在Github上公开了project，如果你想加入合作者，请告诉我？

我正在对UICollectionViewFlowLayout进行子分类，并实施了以下内容：

- (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;
}

还试图在UICollectionViewController中实现它：

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

你知道怎么保持这个尺寸吗？

Answer 1

我遇到了同样的问题，原因是你需要调用委托的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;
}