从UICollectionView中删除单元格而不从顶部重新加载

Question

我在我的ios应用程序中使用CollectionView.每个集合单元格都包含一个删除按钮 通过单击按钮,应删除单元格.删除后,该空间将填充下面的单元格(我不希望重新加载CollectionView并再次从顶部开始)

如何使用autolayout从UICollectionView中删除特定单元格？

Answer 1

UICollectionView将在删除后动画并自动重新排列单元格.

从集合视图中删除所选项目

[self.collectionView performBatchUpdates:^{

    NSArray *selectedItemsIndexPaths = [self.collectionView indexPathsForSelectedItems];

    // Delete the items from the data source.
    [self deleteItemsFromDataSourceAtIndexPaths:selectedItemsIndexPaths];

    // Now delete the items from the collection view.
    [self.collectionView deleteItemsAtIndexPaths:selectedItemsIndexPaths]; 

} completion:nil];



// This method is for deleting the selected images from the data source array
-(void)deleteItemsFromDataSourceAtIndexPaths:(NSArray  *)itemPaths
{
    NSMutableIndexSet *indexSet = [NSMutableIndexSet indexSet];
    for (NSIndexPath *itemPath  in itemPaths) {
        [indexSet addIndex:itemPath.row];
    }
    [self.images removeObjectsAtIndexes:indexSet]; // self.images is my data source

}

Answer 2

没有像UITableviewController那样向UICollectionViewController提供委托方法.我们可以通过向UICollectionView添加长手势识别器来手动完成.

 UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self
                                                                                         action:@selector(activateDeletionMode:)];
 longPress.delegate = self;
 [collectionView addGestureRecognizer:longPress];

在longGesture方法中,在该特定单元格上添加按钮.

- (void)activateDeletionMode:(UILongPressGestureRecognizer *)gr
{
    if (gr.state == UIGestureRecognizerStateBegan) {
        if (!isDeleteActive) {
        NSIndexPath *indexPath = [collectionView indexPathForItemAtPoint:[gr locationInView:collectionView]];
        UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
        deletedIndexpath = indexPath.row;
        [cell addSubview:deleteButton];
        [deleteButton bringSubviewToFront:collectionView];
        }
     }
 }

在那个按钮动作中,

- (void)delete:(UIButton *)sender
{
    [self.arrPhotos removeObjectAtIndex:deletedIndexpath];
    [deleteButton removeFromSuperview];
    [collectionView reloadData];
}

我认为它可以帮到你.