[英]Cell reordering in CollectionView in iOS
我试图在collectionView中重新排序单元格,但是没有调用集合View delgate方法。 我已正确设置了委托。
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath )sourceIndexPath toIndexPath:(NSIndexPath )destinationIndexPath
这是我的工作准则。
- (void)viewDidLoad {
[super viewDidLoad];
UILongPressGestureRecognizer *longGesture=[[UILongPressGestureRecognizer alloc] init];
[longGesture addTarget:self action:@selector(handleGesture:)];
[self.collectionView addGestureRecognizer:longGesture];
NSLog(@"The array is %@",dataArray);
self.collectionView.delegate=self;
[_collectionView reloadData];
// Do any additional setup after loading the view, typically from a nib.
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return [dataArray count];
}
// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
MyCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
cell.cellImageView.image = [dataArray objectAtIndex:indexPath.row];;
return cell;
}
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath{
return YES;
}
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath{
UIImage *sourceImage = [dataArray objectAtIndex:sourceIndexPath.row];
UIImage *destImage = [dataArray objectAtIndex:destinationIndexPath.row];
[arr insertObject:destImage atIndex:sourceIndexPath.row];
[arr insertObject:sourceImage atIndex:destinationIndexPath.row];
}
-(void)handleGesture:(UILongPressGestureRecognizer*)gesture{
switch (gesture.state) {
case UIGestureRecognizerStateBegan:{
NSIndexPath *indexPath=[self.collectionView indexPathForItemAtPoint:[gesture locationInView:self.collectionView]];
if(indexPath!=nil)
[self.collectionView beginInteractiveMovementForItemAtIndexPath:indexPath];
break;
}
case UIGestureRecognizerStateChanged:{
[self.collectionView updateInteractiveMovementTargetPosition:[gesture locationInView:self.collectionView]];
}
case UIGestureRecognizerStateEnded:{
[self.collectionView endInteractiveMovement];
}
default:
[self.collectionView cancelInteractiveMovement];
break;
}
}
为每个case语句添加一个break,你的代码运行正常!
这可能是将Swift示例代码转换为Objective C的结果。
我想您忘记设置datasource
因此在viewDidload
添加以下行,
self.collectionView.datasource = self;
并确保您已确认这两个协议,
<UICollectionViewDataSource,UICollectionViewDelegate>
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