Question

I am using the AVAudioPlayer framework, and I have several sounds that play one at a time. When a sound is finished playing, I want the application to do something. I tried to use audioPlayerDidFinishPlaying to do the action at the end of the first sound, but I couldn’t use that for the second sound because I got a redefinition error. Can I use NSTimeInterval to get the duration of a sound?

//  ViewController.h
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <AVFoundation/AVAudioPlayer.h>

@interface ViewController : UIViewController {  
UIButton        *begin;
UIWindow        *firstTestWindow;
UIWindow        *secondTestWindow;
AVAudioPlayer   *player;
NSTimeInterval  duration;
}  

@property (nonatomic, retain) IBOutlet UIButton     *begin;
@property (nonatomic, retain) IBOutlet UIWindow     *firstTestWindow;
@property (nonatomic, retain) IBOutlet UIWindow     *secondTestWindow;
@property (nonatomic, retain)         AVAudioPlayer   *player;
@property (readonly)                   NSTimeInterval  duration;


- (IBAction)begin:(id)sender;
- (IBAction)doTapScreen:(id)sender;

@end



//ViewController.m
#import "ViewController.h"

@implementation ViewController

@synthesize begin, player, firstTestWindow, secondTestWindow;

//first sound
- (IBAction)begin:(id)sender; {

    [firstTestWindow makeKeyAndVisible];
    NSString *soundFilePath =
    [[NSBundle mainBundle] pathForResource: @"Tone1"
                                    ofType: @"mp3"];

    NSURL *fileURL = [[NSURL alloc] initFileURLWithPath: soundFilePath];

    AVAudioPlayer *newPlayer =
    [[AVAudioPlayer alloc] initWithContentsOfURL: fileURL
                                           error: nil];
    [fileURL release];
    self.player = newPlayer;
    [newPlayer release];

    [player prepareToPlay];
    [self.player play];

}

//If user does not do anything by the end of the sound go to secondWindow
- (void) audioPlayerDidFinishPlaying: (AVAudioPlayer *) player
                    successfully: (BOOL) flag {
                               if (flag==YES) {
    [secondWindow makeKeyAndVisible];
    }
}

//second sound
- (IBAction)doTapScreen:(id)sender {
    //When user touches the screen, either play the sound or go to the next window
    if (self.player.playing) {
    [self.player stop];
    [thirdWindow makeKeyAndVisible];
    }

    else {
    NSString *soundFilePath =
    [[NSBundle mainBundle] pathForResource: @"Tone2"
                ofType: @"mp3"];

    NSURL *fileURL = [[NSURL alloc] initFileURLWithPath: soundFilePath];

    AVAudioPlayer *newPlayer =
    [[AVAudioPlayer alloc] initWithContentsOfURL: fileURL
                                           error: nil];
    [fileURL release];
    self.player = newPlayer;
    [newPlayer release];

    [player prepareToPlay];
    [self.player play];

}
}

Answer 1

When a sound is finished playing, I want the application to do something.

Then set yourself as the delegate and respond to audioPlayerDidFinishPlaying:successfully:.

In the code snippet you showed, you’ve done step 2 but not step 1: You’re not setting yourself as the delegate.

I tried to use applicationDidFinishLaunching to do the action at the end of the first sound …

Brain fart? That method has nothing that I can see to do with playing sounds.

…, but I couldn’t use that for the second sound because I got a redefinition error.

Huh? Did you implement the method twice or something instead of just comparing the player object in the method body?

It would help if you showed the exact error message you got.