UIActivityIndicator not showing up

Question

I have implemented a UIActivityIndicator that shows up in one part of my program but not another. I have the activity indicator come up while i am loading a table, however, i am trying to get it to start animating again after the user has clicked a button and is waiting for the table to reload. The table reloads, but no indicator. Here is the code.

- (void)viewWillAppear:(BOOL)animated {

CGRect frame = CGRectMake (120.0, 185.0, 80, 80);
activity = [[UIActivityIndicatorView alloc] initWithFrame: frame];
activity.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;
[activity startAnimating];

[navigationUpdateFromDetail.window addSubview: activity];

[super viewWillAppear:animated];
}

It comes up for that part. However, for the next part it does not want to seem to come up.

- (IBAction) btnGreaterTen_clicked :(id)sender{

self.searchDistance = [NSNumber numberWithDouble : 10];

CGRect frame = CGRectMake (120.0, 185.0, 80, 80);

activity = [[UIActivityIndicatorView alloc] initWithFrame: frame];
activity.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;

[navigationUpdateFromDetail.window addSubview: activity];
[activity startAnimating];


NSLog(@" search value after change %@", [searchDistance description]);

[self getSetDisplay];

[activity stopAnimating];

}

That button changes a variable and is suppose to start the animation, but it does not. I have changed the color to make sure it was not just blending in, so that is not the solution. I tried to recreate the same object, but still no luck. Thank you in advance.

Answer 1

try adding

activity.hidden = NO;

just before

[activity startAnimating];

Answer 2

That won't work, because the animation will only show when the main application loop is "running". In your code, you're blocking the main thread by calling [self getSetDisplay].

You should load your data asynchronously to make this work (in a background thread). Then you can call startAnimating, start your thread, and when the thread finishes, stop the animation.