添加新單元格時更新集合視圖

Question

在我的應用程序中，我一張一張地捕獲圖像，我在最后一個索引中顯示了“添加更多”單元，添加新圖像后，我希望此“添加更多”單元可見，在3-4張圖像之后“添加更多” ”單元格被隱藏了。 如何更新收藏夾視圖，以使“添加更多”單元格始終可見。 謝謝 ：）

添加圖像的代碼：

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

CollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];


if (indexPath.row == [imageArray count]) {

    cell.ImageImg.image =[UIImage imageNamed:@"plus.jpg"];
    cell.DeleteBtn.hidden=true;
    [cell.ImageImg.layer setBorderColor: [[UIColor clearColor] CGColor]];
    [cell.ImageImg.layer setBorderWidth: 0.5];

}

else
{
    cell.DeleteBtn.hidden=false;

    cell.ImageImg.image=[imageArray objectAtIndex:indexPath.row];
    [cell.ImageImg.layer setBorderColor: [[UIColor blackColor] CGColor]];
    [cell.ImageImg.layer setBorderWidth: 0.7];
    [cell.DeleteBtn addTarget:self action:@selector(RemovePrssd:) forControlEvents:UIControlEventTouchUpInside];

}

return cell;
}
-(void)RemovePrssd:(id)sender{

UIView *senderButton = (UIView*) sender;
NSIndexPath *indexPath = [_ImageCollectionVIew indexPathForCell: (UICollectionViewCell *)[[senderButton superview]superview]];

[imageArray removeObjectAtIndex:indexPath.row];
[_ImageCollectionVIew deleteItemsAtIndexPaths:[NSArray arrayWithObject:indexPath]];
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath  {
    if (indexPath.row == [imageArray count]) {

        value=@"0";
        [_videoController.view removeFromSuperview ];
        UIImagePickerController *picker = [[UIImagePickerController alloc] init];
        picker.delegate = self;
        picker.allowsEditing = YES;
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        [self presentViewController:picker animated:YES completion:NULL];
    }

}

Answer 1

添加以下方法，並在您要添加新單元格的地方調用它。

-(void)scrollToBottom
{
CGFloat collectionViewContentHeight = _ImageCollectionVIew.contentSize.height;
CGFloat collectionViewFrameHeightAfterInserts = _ImageCollectionVIew.frame.size.height - (_ImageCollectionVIew.contentInset.top + _ImageCollectionVIew.contentInset.bottom);

if(collectionViewContentHeight > collectionViewFrameHeightAfterInserts) {
    [_ImageCollectionVIew setContentOffset:CGPointMake(0,_ImageCollectionVIew.contentSize.height - _ImageCollectionVIew.frame.size.height) animated:NO];
    }
}