iphone - 当声音在 AVAudioPlayer 中播放完毕时执行操作吗？

Question

我正在使用 AVAudioPlayer 框架，并且我有几种声音一次播放一种。当声音播放完毕后，我希望应用程序执行一些操作。我尝试使用audioPlayerDidFinishPlaying 在第一个声音结束时执行操作，但我无法将其用于第二个声音，因为我遇到了重新定义错误。我可以使用 NSTimeInterval 来获取声音的持续时间吗？

//  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.

然后将自己设置为委托(delegate)并响应 audioPlayerDidFinishPlaying:successively:。

在您显示的代码片段中，您已完成步骤 2，但未完成步骤 1:您没有将自己设置为委托(delegate)人。

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

脑放屁？我认为该方法与播放声音无关。

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

嗯？您是否实现了该方法两次或其他内容，而不是仅比较方法主体中的玩家对象？

如果您显示收到的确切错误消息，将会有所帮助。