UICollectionview 允许多个选择不起作用 xcode
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原文地址: http://stackoverflow.com/questions/20090657/
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UICollectionview allows multipleSelection not working xcode
提问by user241641
How to select the Collection Viewcell images using allows multiple selection is not working. Please suggest me idea or links
如何Collection View使用允许多选来选择单元格图像不起作用。请建议我的想法或链接
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(@"photo viewer");
[self.collectionView setPagingEnabled:NO];
self.collectionView.allowsSelection=YES;
[self.collectionView registerClass:[CWPhotoGalleryCell class]
forCellWithReuseIdentifier:CWPhotoGalleryCellIdentifier];
[self.collectionView scrollToItemAtIndexPath:self.selectedIndexPath atScrollPosition:UICollectionViewScrollPositionRight animated:YES];
}
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:
(NSInteger)section
{
return [self.imageArray count];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
CWPhotoGalleryCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CWPhotoGalleryCellIdentifier
forIndexPath:indexPath];
cell.navigationControllerContainer = self.navigationController;
ALAsset *photo = [self.imageArray objectAtIndex:indexPath.row];
ALAssetRepresentation *rep = [photo defaultRepresentation];
CGImageRef ref = [rep fullScreenImage];
UIImage *img = [[UIImage alloc] initWithCGImage:ref];
cell.image = img;
NSLog(@"clicked");
return cell;
}
-(CGSize)collectionView:(UICollectionView *)collectionView
layout:(UICollectionViewLayout *)collectionViewLayout
sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
return self.view.bounds.size;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
回答by Greg
To select single or multiple items in collection view you need to implement UIColectionViewDelegate. You also need to add NSMutableArray where you will keep selected items (selectedItems).
要在集合视图中选择单个或多个项目，您需要实现 UICollectionViewDelegate。您还需要添加 NSMutableArray，您将在其中保留所选项目 (selectedItems)。
#pragma mark - UICollectionViewDelegate
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
Item *item = self.yourArray[indexPath.row];
[selectedItems addObject: item];
}
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
Item *item = self.yourArray[indexPath.row];
[selectedItems removeObject:item];
}
The last thing left to do is add button to toogle between selected and non-selected state:
剩下要做的最后一件事是添加按钮以在选中和未选中状态之间切换：
-(IBAction)toogleButtonPressed:(id)sender
{
UIBarButtonItem *toogleButton = (UIBarButtonItem *)sender;
if (!self.selected)
{
self.selected = YES;
[toogleButton setTitle:@"Done"];
[self.collectionView setAllowsMultipleSelection:YES];
}
else
{
self.selected = NO;
[toogleButton setTitle:@"Select"];
[self.collectionView setAllowsMultipleSelection:NO];
for(NSIndexPath *iP in self.collectionView.indexPathsForSelectedItems)
{
[self.collectionView deselectItemAtIndexPath:iP animated:NO];
}
[selectedItems removeAllObjects];
}
}
Hope this help.
希望这有帮助。
