How to access a UIActivityIndicatorView in a UITableView's section header view?

I want to do something pretty simple with my UITableView: I want to add a UIActivityIndicatorView to a section's header view, and make it animate or disappear whenever I want.

I had no trouble adding the UIActivityIndicatorView to the header view using tableView:viewForHeaderInSection:

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
UIView* customView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 60.0)];

// create the title
UILabel * headerLabel = [[UILabel alloc] initWithFrame:CGRectMake(15.0, 12.0, 310.0, 22.0)];
headerLabel.text = @"some random title here";

[customView addSubview:headerLabel];
[headerLabel release];

// Add a UIActivityIndicat开发者_如何学JAVAorView in section 1
if(section == 1)
{
    [activityIndicator startAnimating];
    [customView addSubview:activityIndicator];
}

return [customView autorelease];

}

activityIndicator is a property of my controller's class. I alloc it in the viewDidLoad method:

- (void)viewDidLoad 
{ 
(...)
activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(200, 10, 25, 25)];
}

This way I can send messages to it (like -startAnimating or -stopAnimating) whenever I want. The problem is that the activityIndicator disappears as soon as I scroll the tableView (I guess it is because the tableView:viewForHeaderInSection: method is called a second time).

How else can I add an activityIndicatorView to the section's header view and still be able to send messages to it afterwards? (with the activityIndicator not disapearing when I scroll down of course)

Thank you very much!

If you try to use the same activity indicator in multiple places then it is probably getting moved from one place to the other. I believe you need a different one for every single section header. You might want to use a MutableArray to keep track of the header views you create so you can reuse them if you find one in the array that doesn't have a superview, sort of like dequeuing and reusing cells.

This is just a guess as I haven't done this, but I'm pretty sure the issue is trying to reuse the same view in multiple places.

The problem seemed to be caused by re-creating a customView and adding the activityIndicator as a subview every time tableView:viewForHeaderInSection: is called.

Not using subviews helped me fix it:

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{

// Add a UIActivityIndicatorView in section 1
if(section == 1)
{
    [activityIndicator startAnimating];
    return activityIndicator;
}

    UIView* customView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 60.0)];

// create the title
UILabel * headerLabel = [[UILabel alloc] initWithFrame:CGRectMake(15.0, 12.0, 310.0, 22.0)];
headerLabel.text = @"some random title here";

[customView addSubview:headerLabel];
[headerLabel release];


return [customView autorelease];
}

(it looks quite ugly though, the activityIndicator takes the whole width of the section. I'd better create a unique customView for section 1 and add the activityIndicator as a subView once and for all).