UICollectionView move specific cell

Question

I have a working sample of UICollectionView, I can move a cell [by indexPath], but I need a specific cell [indexpath.row?] So I move the cell i need, At the moment a cell moves but not the correct one, so when I move for example

NSIndexPath *index = [indexPaths objectAtIndex:0];

the cell on indexpath.row = 3 moves, how to call the cell by indexpath row?

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.view.backgroundColor = [UIColor lightGrayColor];

    CGRect frame = CGRectMake(10, 100, 300, 500);

    UICollectionViewFlowLayout *layout=[[UICollectionViewFlowLayout alloc] init];
    self.collectionView=[[UICollectionView alloc] initWithFrame:frame collectionViewLayout:layout];
    [self.collectionView setDataSource:self];
    [self.collectionView setDelegate:self];

    [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"cellIdentifier"];
    [self.collectionView setBackgroundColor:[UIColor redColor]];

    [self.view addSubview:self.collectionView];


    UIButton *animus = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    animus.frame = CGRectMake(100, 20, 90, 30);
    [animus setTitle:@"Animus" forState:UIControlStateNormal];
    [animus addTarget:self action:@selector(animusPressed:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:animus];

}

- (void)animusPressed:(id)sender
{
    NSIndexPath *index = [indexPaths objectAtIndex:0]; //en el index!

 NSLog(@"moving tha cell :: %d", index.row);


    __weak UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:index]; // Avoid retain cycles

    CGRect frame = cell.frame;

    frame.origin.y = 300;

    cell.frame = frame;
}


- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];

    cell.backgroundColor=[UIColor greenColor];

    UILabel *title = [[UILabel alloc]initWithFrame:CGRectMake(0, 10, cell.bounds.size.width, 40)];
    [cell.contentView addSubview:title];
    NSString *titleLbl = [NSString stringWithFormat:@"i = %d", indexPath.row];
    title.text = titleLbl;

    return cell;
}

So a cell moves, but not the one I want, I need to move a specific cell, by indexpath.row like it is shown on the cellForRow,

How to specify what cell I want to move?

Please note im moving cell on index = 0 , but the indexpath.row = 2 is the one moving

Thanks

Answer 1

Have you tried something like this?

[NSIndexPath indexPathForItem:0 inSection:0]

Answer 2

First of all, it will be more difficult to make any adjustments your UICollectionView without using an array as your data source. Most commonly, you will have one array holding data and in your cellForItemAtIndexPath: method you grab index-specific data from that array via:

MyData *myData = [self.arrayOfMyData objectAtIndex:indexPath.row];

This way you can populate the cell using data related to the current indexPath. Once you do that, just update your data array and then call:

[self.collectionView reloadData];

Then the updates will be represented in the collection view. If you want to animate those changes, use:

[self.collectionView performBatchUpdates:^{
    [self.collectionView reloadData];
} completion:nil];

If you want to "move" cells around with the appearance that it changed its original position, you could manage your arrayOfMyData to add a signifier at the index you want empty to set the background of the cell as clear and put the cell to move at the end of your array, then call reloadData.