CODEWITHSUNDEEP
iosobjective-ccocoa-touchuitableviewuiviewanimation
Michael Wilson
Michael Wilson

Reputation: 861

Interrupt UITableView cell resize animation?

I have a UITableView, and when it stops scrolling (scrollViewDidEndDecelerating:) the height of the current cell expands by setting the variable currentRow and reloading:

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    CGFloat current_offset = self.tableView.contentOffset.y;
    currentRow = [self.tableView indexPathForRowAtPoint:CGPointMake(0, current_offset)].row;
    [self.tableView beginUpdates];
    [self.tableView endUpdates];
};

The animation works fine, but it temporarily prevents the tableview from being scrollable/interactive. So if I touch the screen while the cell is expanding, I end up not being able to scroll unless I try again.

Is there a workaround or another way to achieve the same effect?

Upvotes: 6

Views: 1098

Answers (5)

Daniel
Daniel

Reputation: 598

Try this: 

[CATransaction begin];

[self.tableView beginUpdates];


[CATransaction setCompletionBlock: ^{
    // Code to be executed upon completion
   CGFloat current_offset = self.tableView.contentOffset.y;
   currentRow = [self.tableView indexPathForRowAtPoint:CGPointMake(0, current_offset)].row;
}];


[self.tableView endUpdates];

[CATransaction commit];

Lastly you might want to commit animations also for the tableview

Upvotes: 1

memmons
memmons

Reputation: 40502

The UITableView animation system is completely opaque. There is no API that let's you modify or override what happens beyond selecting what type of animation occurs for inserts/deletes. Peruse the header file and look at the stack traces.

So, there is no practical way to prevent UITableView animations from blocking touches, nor should you want to. Doing so could lead to manipulating a dequeued cell. So, unless you are fond of EXC_BAD_ACCESS errors, don't do that.

Note that that user interactions are disabled for all UITableView animations, not just updates -- inserts, deletes, and reloads are handled the same way.

It seems like a reasonable hook to have into UITableView animations, though, so be sure to submit a bug report to Apple and maybe we'll see it in a future enhancement.

Upvotes: 1

l0gg3r
l0gg3r

Reputation: 8954

You can use this method, to stop animations,
but I'm not sure that it will not make problems.

- (void)stopAnimations
{
    for (UITableViewCell *cell in [self.tableView visibleCells]) {
        [cell.layer removeAllAnimations];
    }
}

Try adding this on your TableViewController 

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self stopAnimations];
}

or try to add tap gesture recognizer to Application's window and then call stopAinimations on gesture trigger.

Upvotes: 4

Sasi
Sasi

Reputation: 1897

It is not possible to interrupt tableview animation also it is not advisable. If you want the tableview to be responsible on first touch you can use reloadData method instead of beginUpdates else try using reloadSection method. It may help but preventing the animation is not good idea.

Upvotes: 1

E. Rivera
E. Rivera

Reputation: 10938

If you are using iOS 7+ you could try calling the table updates inside a [UIView performWithoutAnimation:] block.

Upvotes: 1

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