UIBarButtonItem after animating disappears

Question

I have the UIBarButtonItem (configurated in interface builder). If a user click this button, the "heavy process" will be started and for better user experience I want to change this button with (UIActivityIndicatorView). I do it in the following way:

    self.indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];   
    indicator.hidesWhenStopped = YES;
    [self.heavyBarButton initWithCustomView:self.indicator];

    [self.indicator startAnimating];

    [NSThread detachNewThreadSelector:@selector(animateHeavyProcess) toTarget:self withObject:nil];

animateHeavyProcess:

     [self heavyProcess];
     [self.indicator stopAnimating];
     UIBarButtonItem *originalButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"maximize.png"] style:UIBarButtonItemStylePlain target:self action:@selector(startProcessClick:)];
     self.heavyBarButton = originalButton;
     [originalButton release];

What happens: after a user clicks the BarButton animation will be started and after processing button disappears. However, I want that the original button will be shown again.

Where Are you getting issue?what is your issue?your question is not clear. — Dinesh Raja, Mar 02 '12 at 13:06

score 0 · Answer 1 · edited May 23 '17 at 12:21

0

what if you use Grand Central Dispatch for the heavy process? I would think it's more convenient. But remember that you can not use any of the UI in that block. Here is an example: iphone ios running in separate thread

edited May 23 '17 at 12:21

Community

1
1

answered Mar 02 '12 at 13:09

Adrian Ancuta

1,036
9
16

score 0 · Answer 2 · answered Mar 02 '12 at 23:23

You should not be doing UI updates in a secondary thread; calls to UIKit should be on the main thread.

You can split out the UI updating part of your code:

- (void)restoreBarButtonItem
{
  [self.indicator stopAnimating];
  UIBarButtonItem *originalButton = [[UIBarButtonItem alloc] 
     initWithImage:[UIImage imageNamed:@"maximize.png"]
     style:UIBarButtonItemStylePlain
     target:self
     action:@selector(startProcessClick:)];
  self.heavyBarButton = originalButton;
  [originalButton release];
}

And then in your heavy process (running on the secondary thread) just call this new UI update method on the main thread:

- (void)animateHeavyProcess
{
  [self heavyProcess];
  [self performSelectorOnMainThread:@selector(restoreBarButtonItem:)
    withObject:nil
    waitUntilDone:NO];
}

score -1 · Answer 3 · answered Mar 02 '12 at 23:12

-1

You should use UIToolbar's setItems:animated: method to replace buttons.

answered Mar 02 '12 at 23:12

greenhorn

1,097
6
10

UIBarButtonItem after animating disappears

3 Answers3