Check if a subview is in a view

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 :

Objective-C

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

Swift 3

@IBAction func showPopup(sender: AnyObject) {
    if !self.myView.isDescendant(of: self.view) {
        self.view.addSubview(self.myView)
    } else {
        self.myView.removeFromSuperview()
    }
}