如何从UICollectionViewCell访问UICollectionView中Cell的indexPath

Question

i want to animate the UICollectionViewCell when action is called.
i have done UICollectionViewCell in Interface Builder , the UICollectionView also. Now i want to get the correct indexPath at my actionBtnAddToCard method.

thats the way i try it now (method in ProduktViewCell.m):

- (IBAction)actionAddToCart:(id)sender {
    XLog(@"");

    // see this line
    NSIndexPath *indexPath = ??** how can i access the correct indexPath**??;
    SortimentViewController *svc = [[SortimentViewController alloc] initWithNibName:@"SortimentViewController_iPad" bundle:[NSBundle mainBundle]];
    [svc.collectionViewProdukte cellForItemAtIndexPath:indexPath];

    [svc collectionView:svc.collectionViewProdukte didSelectItemAtIndexPath:indexPath];
} 

SortimentViewController is the viewController which inherits the UICollectionView.
how to acces the correct indexPath?

UPDATE 1: edited post for better understanding.

Answer 1

- (IBAction)actionAddToCart:(id)sender {
   NSIndexPath *indexPath;
   indexPath = [self.collectionView indexPathForItemAtPoint:[self.collectionView convertPoint:sender.center fromView:sender.superview]]; 
   ...
}

Answer 2

if you know the view hierarchy it is easy.

UIButton *button = (UiButton *) sender;

if the button is like this - > UITableViewCell - > button

then you can get cell like this

UITableViewCell *cell = (UITableViewCell *)[button superview];

if the button is like this - > UITableViewCell - > content view -> button

UITableViewCell *cell = (UITableViewCell *)[[button superview] superview];

and finally index path can be extracted like this

NSIndexPath *indexPath = [self.table_View indexPathForCell:cell];

Answer 3

Do Not Depend on view. Try this.

CGPoint buttonPosition = [sender convertPoint:CGPointZero toView:self.collectionView];
NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:buttonPosition];

NSLog(@"%ld", (long)indexPath.row);

Answer 4

Using code like [[button superview] superview] is fragile and not future-proof; indeed, it's not even guaranteed to work on all iOS versions unless you explicitly test it. I always use an iterative helper method for this purpose:-

- (UIView *)superviewWithClassName:(NSString *)className fromView:(UIView *)view
{
    while (view)
    {
        if ([NSStringFromClass([view class]) isEqualToString:className])
        {
            return view;
        }
        view = view.superview;
    }
    return nil;
}

Then I call it from the button handler like so:-

- (IBAction)buttonClicked:(id)sender
{
    UIButton *button = (UIButton *)sender;
    UICollectionViewCell *cell = (UICollectionViewCell *)
                                [self superviewWithClassName:@"UICollectionViewCell"
                                fromView:button];
    if (cell)
    {
        NSIndexPath *indexPath = [self.collectionView indexPathForCell:cell];
        // do whatever action you need with the indexPath...
    }
}

UPDATE: Swift version of superviewWithClassName . Made it a class method since it never references self .

static func superviewWithClassName(className:String, fromView view:UIView?) -> UIView? {
    guard let classType = NSClassFromString(className) else {
        return nil
    }
    var v:UIView? = view
    while (v != nil) {
        if v!.isKindOfClass(classType) {
            return v
        }
        v = v!.superview
    }
    return nil
}

and some code to call it, either from prepareForSegue or a button handler:-

guard let cell = UIView.superviewWithClassName("UICollectionViewCell", fromView: sender as? UIView) as? UITableViewCell else {return}

Answer 5

Swift solution: A UICollectionView extension like this one can be useful for this.

extension UICollectionView {
    func indexPathForView(view: AnyObject) -> NSIndexPath? {
        let originInCollectioView = self.convertPoint(CGPointZero, fromView: (view as! UIView))
        return self.indexPathForItemAtPoint(originInCollectioView)
    }
}

Usage becomes easy everywhere.

let indexPath = collectionView.indexPathForView(button)

Answer 6

你可以这样做，indexPathsForVisibleItems将返回当前在视图中可见的项目的NSIndexPaths数组，第一个对象返回第一个（如果每个视图有一个单元格）。

NSIndexPath *indexPath = [[svc.collectionViewProdukte indexPathsForVisibleItems] firstObject]

Answer 7

If you want to animate a specific cell, you need to get a reference to that cell. Simply calling

[svc.collectionViewProdukte cellForItemAtIndexPath:indexPath];

does nothing. You need to keep the cell that the method returns, like this:

UICollectionViewCell *cell = [svc.collectionViewProdukte cellForItemAtIndexPath:indexPath];

After that, go ahead and animate:

[UIView animateWithDuration:0.2f animations:^{
    cell.transform = CGAffineTransformMakeScale(0.5f, 0.5f);
}];

Answer 8

Swift 3 Solution : Based on Ishan Handa's Answer

extension UICollectionView {
func indexPathForView(view: AnyObject) -> IndexPath? {
    let originInCollectioView = self.convert(CGPoint.zero, from: (view as! UIView))
    return self.indexPathForItem(at: originInCollectioView) as IndexPath?
  }
}

Usage:

func deleteCell(sender:UIButton){
    var indexPath:IndexPath? = nil
    indexPath = self.collectionView.indexPathForView(view: sender)        
    print("index path : \(indexPath)")
}

Answer 9

//Note: this is for a storyboard implementation

// here is code for finding the row and section of a textfield being edited in a uicollectionview
UIView *contentView = (UIView *)[textField superview];
UICollectionViewCell *cell = (UICollectionViewCell *)[contentView superview];
cell = (UICollectionViewCell *)[contentView superview];

// determine indexpath for a specific cell in a uicollectionview
NSIndexPath *editPath = [myCollectionView indexPathForCell:cell];
int rowIndex = editPath.row;
int secIndex = editPath.section;

Answer 10

Even though many answer i found here .this will be shortest and useful irrespective of the view hierarchy

- (void) actionAddToCart:(id)sender
{
    id view = [sender superview];

    while (view && [view isKindOfClass:[UICollectionViewCell class]] == NO) 
    {
        view = [view superview];
    }
    NSIndexPath *thisIndexPath = [self.collectionView indexPathForCell:view];

    NSLog(@"%d actionAddToCart pressed",thisIndexPath.row);
}

Answer 11

You almost certainly have a UICollectionViewCell subclass. Just add a property and set the indexPath in cellForItemAtIndexPath.

Answer 12

Xcode10. Swift 4.2 version.

extension UICollectionView {

  func indexPathForView(view: AnyObject) -> IndexPath? {
      guard let view = view as? UIView else { return nil }
      let senderIndexPath = self.convert(CGPoint.zero, from: view)
      return self.indexPathForItem(at: senderIndexPath)
  }

}

Usage:

// yourView can be button for example
let indexPath = collectionView.indexPathForView(view: yourView)