Start AVAudioPlayer in App Delegate and make it available to all view controllers?

[Whitehk]

Hi. I am trying to figure out how to make an AVAudioPlayer controllable (play, stop) throughout my app. I am doing this by starting it in my app delegate. The only thing is, I still get errors when I try to stop it in a different view controller. Here's how I did it:

MyAppDelegate.h:

#import <UIKit/UIKit.h>
#import <AVFoundation/AVAudioPlayer.h>
#import "MainMenu.h"

@interface MyAppDelegate : NSObject <UIApplicationDelegate> {
	UIWindow *window;
	MainMenu *viewController;
	
	AVAudioPlayer *backgroundMusic;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet MainMenu *viewController;

@end

MyAppDelegate.m:

#import "MyAppDelegate.h"
#import "MainMenu.h"

@implementation MyAppDelegate

@synthesize window;
@synthesize viewController;

- (void)applicationDidFinishLaunching:(UIApplication *)application {    
	
	viewController = [[MainMenu alloc] init];
	// Override point for customization after app launch    
	[window addSubview:[viewController view]];
	
	[window makeKeyAndVisible];
	
	NSString *backgroundMusicPath = [[NSBundle mainBundle] pathForResource: @"backgroundmusic" ofType: @"wav"];
	NSURL *backgroundMusicURL = [[NSURL alloc] initFileURLWithPath:backgroundMusicPath];
	backgroundMusic = [[AVAudioPlayer alloc] initWithContentsOfURL:backgroundMusicURL error:nil];
	[backgroundMusic play];
	backgroundMusic.numberOfLoops = -1;
	
	backgroundMusic.volume = 0.5;
}


- (void)dealloc {
	[viewController release];
	[window release];
	[super dealloc];
}


@end

------------------------
I want the backgroundMusic to play in the Main Menu (which, you could probably see, appears when the user starts the app, so that's why I started playing it in the delegate). However, when the user actually starts playing the game, I want it to stop (which is in a different view controller named level1). I get the variable by just doing #import MyAppDelegate.h into the level1.m file and did the normal [backgroundMusic stop]; to stop the music in the viewDidLoad method. However, backgroundMusic is still undeclared. I am at a complete loss. Sorry for this completely noob question. Thanks for the help in advance!

[Whitehk]

Originally Posted by Whitehk

Hi. I am trying to figure out how to make an AVAudioPlayer controllable (play, stop) throughout my app. I am doing this by starting it in my app delegate. The only thing is, I still get errors when I try to stop it in a different view controller. Here's how I did it:

MyAppDelegate.h:

#import <UIKit/UIKit.h>
#import <AVFoundation/AVAudioPlayer.h>
#import "MainMenu.h"

@interface MyAppDelegate : NSObject <UIApplicationDelegate> {
	UIWindow *window;
	MainMenu *viewController;
	
	AVAudioPlayer *backgroundMusic;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet MainMenu *viewController;

@end

MyAppDelegate.m:

#import "MyAppDelegate.h"
#import "MainMenu.h"

@implementation MyAppDelegate

@synthesize window;
@synthesize viewController;

- (void)applicationDidFinishLaunching:(UIApplication *)application {    
	
	viewController = [[MainMenu alloc] init];
	// Override point for customization after app launch    
	[window addSubview:[viewController view]];
	
	[window makeKeyAndVisible];
	
	NSString *backgroundMusicPath = [[NSBundle mainBundle] pathForResource: @"backgroundmusic" ofType: @"wav"];
	NSURL *backgroundMusicURL = [[NSURL alloc] initFileURLWithPath:backgroundMusicPath];
	backgroundMusic = [[AVAudioPlayer alloc] initWithContentsOfURL:backgroundMusicURL error:nil];
	[backgroundMusic play];
	backgroundMusic.numberOfLoops = -1;
	
	backgroundMusic.volume = 0.5;
}


- (void)dealloc {
	[viewController release];
	[window release];
	[super dealloc];
}


@end

------------------------
I want the backgroundMusic to play in the Main Menu (which, you could probably see, appears when the user starts the app, so that's why I started playing it in the delegate). However, when the user actually starts playing the game, I want it to stop (which is in a different view controller named level1). I get the variable by just doing #import MyAppDelegate.h into the level1.m file and did the normal [backgroundMusic stop]; to stop the music in the viewDidLoad method. However, backgroundMusic is still undeclared. I am at a complete loss. Sorry for this completely noob question. Thanks for the help in advance!

Anyone?

[b33rad]

This post is a little old but for future others:

YourAppDelegate *appDelegate = (YourAppDelegate *)[[UIApplication sharedApplication] delegate];
//and then access the variable by appDelegate.variable

So in your case, replace 'YourAppDelegate' with the name of your app delegate and replace 'appDelegate.variable' with 'appDelegate.backgroundMusic' . I am pretty sure that will work.
Don't forget to set backgroundMusic as a property.


Here is the link I found it at. Referencing variables in App Delegate

Referencing AppDelegate instance variables - Stack Overflow