NSProgressIndicator animating disappear when change view - cocoa

Question

My NSProgressIndicator is animating in a view
when I switch to another view ,and switch back
my NSProgressIndicator disappear.
why?
Here is my code for switch to another view
- (void)switchToView:(NSView *)newView withAnimate:(BOOL)animate
{
if ([[rootView subviews] count] != 0)
{
[rootView setWantsLayer:YES];
[rootView displayIfNeeded];
NSTimeInterval duration = [[self window] animationResizeTime:newFrame];
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setDuration:0.25];
[[rootView animator] replaceSubview:[[rootView subviews] objectAtIndex:0] with:newView];
[NSAnimationContext beginGrouping];
if (duration > 0.25) {
[[NSAnimationContext currentContext] setDuration:0.25];
}
else{
[[NSAnimationContext currentContext] setDuration:duration];
}
[[[self window] animator] setFrame:newFrame display:YES animate:YES];
[NSAnimationContext endGrouping];
[NSAnimationContext endGrouping];
[self performSelector:#selector(endAnimation) withObject:nil afterDelay:0.25f];
}
}
-(void)endAnimation{
[[ _mainWindow contentView] setWantsLayer:NO];
}
I just replace a view,and make a fade out animation NSProgressIndicator animating all the time in a view.

Answer 1

I have solve this by myself ,I think it will be helpful for your guys.
I stop my NSProgressIndicator before I want to replace my view with NSProgressIndicator.
then I replace the view with a new view ,if I switch back I will start NSProgressIndicator with a - (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay; method ,just set the delay=0 is OK.
In xib files , you should set NSProgressIndicator DisplayWhenStopped is YES.
And it will work well.
Then reason is after 10.6.5,At least on OS X 10.6.5 and above, as soon as you set an indetermined-progress-indicator's wantsLayer property to YES, the animation stops immediately .
So before it stop immediately ,I stop it by myself.And start it when I want to use it.
NOTICE: You should stop it by yourself better than system does, it can`t work well if system stop it .