Overlay View with Subview, don't know calling VC - iphone

Question

I need a view (infoView) to be displayed as an overlay on top of another view. As this infoView should be callable from every view of the app(e.g. introView), I'd like the code to be in the infoViews VC and just call its methods when an action at the currentView (introView) happens. I can't use push and pop, as I need to change the background color (infoView) and especially the alpha of the calling view (introView), so right now I do it with insertSubview.
My Code by now:
introVC .h
- (IBAction) openInf:(id)sender;
IBOutlet InfoVC *infoScreenVC;
introVC .m
- (IBAction) openInf:(id)sender {
[infoScreenVC openInfoMethod];}
infoVC .h
- (IBAction) closeInfoPressed;
- (void) openInfoMethod;
- (void) closeInfoMethod;
infoVC .m
- (IBAction) closeInfoPressed {
[self closeInfoPressed];}
- (void) closeInfoMethod {
[self.view removeFromSuperview];
[self.xx.view setAlpha:1.0f];}
- (void) openInfoMethod {
self.view.backgroundColor = [UIColor clearColor];
[self.xx.view setAlpha:0.2f];
[((MyAppAppDelegate *)[UIApplication sharedApplication].delegate).window
insertSubview: self.infoScreenVC.view aboveSubview: self.xx.view];}
When I push the button to show the infoView, my NSLogs tell me the method was called, but I can see the Subview wasn't added. I have absolutely no clue what to insert where right now it says xx in my code, as a VC reference from intro doesn't show me the screen.
If I put that code in introVC an modify it, it does show the infoView, calls the correct method to close, but again can't close (when I'm in introVC). I can't figure out how to tell my app who was the calling VC to get back there.
At some point, when all the code was in introVC I managed to even remove the Subview, but couldn't set the Alpha of introVC back to one.
I do struggle with that since two days.. -.- Or is there maybe an easier solution even?
Thank you very much!
//Edit after sergios answer:
intro.m
- (IBAction) openInf:(id)sender {
introViewController *introVC;
[infoScreenVC openInfoMethod:];}
info.h
- (void) openInfoMethod:(introViewController *introVC);
info.m
- (void) openInfoMethod:(introViewController *introVC) { //error occurs here
self.view.backgroundColor = [UIColor clearColor];
[self.introVC.view setAlpha:0.2f];
[((MyAppAppDelegate *)[UIApplication sharedApplication].delegate).window
insertSubview: self.infoScreenVC.view aboveSubview: self.introVC.view];}
and the occurring error says
Expected ')' before 'introVC'
I'm not sure how to pass the VC reference properly.
Thank you for your help!!
//EDIT Working Code:
As it works now, I'd like to sum things up:
- I give the calling VC (introVC) to openInfoMethod on the Action openInf like [infoVC openInfoMethod:introVC].
In openInfoMethod I "save" the calling VC in a local variable of type introVC (?) and add the overlay etc.
When the Action of the infoViewController named closeInfoPressed occurs, it calls infoViewController's method closeInfoMethod like self closeInfoMethod:introVC.
In that method I remove self.view from Superview and set introVC.view's Alpha to 1 like introVC.view setAlpha:1.0f
So the codesnippets are
intro.h
IBOutlet InfoscreenViewController *infoScreenVC;
#property (nonatomic, retain) IBOutlet InfoscreenViewController *infoScreenVC;
- (IBAction) openInf:(id)sender;
intro.m
#synthesize infoScreenVC;
- (IBAction) openInf:(id)sender {
UIViewController *introVC = self;
[infoScreenVC openInfoMethod:introVC];
}
info.h:
- (void) openInfoMethod:(UIViewController *)rootVC;
- (void) closeInfoMethod:(UIViewController *)callingVC;
info.m
- (void) closeInfoMethod:(UIViewController *)callingVC;{
[self.view removeFromSuperview];
[callingVC.view setAlpha:1.0f];
}
- (IBAction) closeInfoPressed{
[self closeInfoMethod:introVC];
[self.view removeFromSuperview];
}

Answer 1

If your problem is "figure out how to tell my app who was the calling VC to get back there", why don't you add a parameter to openInfo selector, like here:
info.h
- (void) openInfoMethod:(introViewController *)introVC;
info.m
- (void) openInfoMethod:(introViewController *)introVC {
<your implementation here>
}
would this work for you?
EDIT: your code from intro.m has got a small problem,
- (IBAction) openInf:(id)sender {
introViewController *introVC;
[infoScreenVC openInfoMethod:];
}
indeed, you are not initializing your introVC variable, so that when you pass it into -openInfoMethod: it will have some weird value and cause a crash.
As far as I can grasp from your code, intro.m should be the implementation file for your introViewController, therefore you can simply call:
[infoScreenVC openInfoMethod:self];
but please, before doing this, confirm that self is actually your introViewController.

Answer 2

This should be ilke this
(void) openInfoMethod:(introViewController *)introvc you are passing parameters in a wrong way.

Answer 3

If I understand your question correctly, your infoView should be a subclass of UIView and instantiated from any of your view controllers using:
InfoView *infoView = [[InfoView alloc] initWithFrame:CGRectMake(originX,originY,width,height)];
Then you simply add it as a subview of your view controllers view:
[self.view addSubView:infoView];
[infoView release]; // It's safe to release it here as your view controller's view is retaining it
And when you are done with it, simply call
[infoView removeFromSuperview];
As an aside, you could create some simple methods inside infoView that include introducing animation when the view is presented or removed. Here's an example for fade in and out which assume you set the alpha to zero initially when you create the view:
- (void)fadeIn {
[UIView animateWithDuration:1.0f animations:^{self.alpha = 1.0f}];
}
And fade out
- (void)fadeOut {
[UIView animateWithDuration:1.0f animations:^{self.alpha = 0f}
completion:^(BOOL finished){self removeFromSuperView}];
}