Check if a subview is in a view in iOS

You are probably looking for UIView's -(BOOL)isDescendantOfView:(UIView *)view; taken in UIView class reference.

Return Value YES if the receiver is an immediate or distant subview of view or if view is the receiver itself; otherwise NO.

You will end up with a code like :

-(IBAction)showPopup:(id)sender {
    if(![[self myView] isDescendantOfView:[self view]]) { 
        [self.view addSubview:[self myView]];
    } else {
        [[self myView] removeFromSuperview];
}