Question

Is there a way to check if a UIViewController is loaded in memory/visible on screen?

Something like this:

if([ContentRvController exists]){
    contentView *ContentRvController = [[contentView alloc] 
        initWithNibName:@"contentView" bundle:nil]; //ContentView is a custom UIViewController
    ....
    //Code to set the UIViewController
    ....
}
else{
    [ContentRvController release];
}

That should happen when a button (that right now initializes the ViewControllers) is tapped. Right now, when tapped it opens n ViewControllers, it is supposed to display only one at a time.

Thats pretty much it, greetings and hope you can help me out.

Answer 1

Is this based on existing code?
Classes should start upper case, and instances should be camel case, e.g.

if([contentRvController exists]){
    ContentView *contentRvController = [[ContentView alloc] 
    initWithNibName:@"contentView" bundle:nil]; //ContentView is a custom UIViewController
    ....
    //Code to set the UIViewController
    ....
}
else{
    [contentRvController release];
}

it is probably worth declaring it in the header, i.e.

@interface SomeClass : NSObject {

}
@property(non-atomic, retain) ContentView *contentRvController;
@end

and then in code you could do

if(contentRvController!=nil){
    ContentView *aView=[[[ContentView alloc] init] autorelease];
    self.contentRvController=aView;
}

Also, don’t do the else{[contentRv release];} bit, if you have autoreleased it anywhere, this will leak at some point.