AVAudioPlayer - 按顺序播放多个音频文件

Question

我想使用 AVAudioPlayer 按顺序（一个接一个）播放多个 MP3 文件。我试了一下，播放第一首MP3后就停止了。但是，如果我进入调试器，它工作正常.. 有什么想法吗？我在某处读到 AVAudioPlayer 在后台播放音频.. 我该如何防止它这样做？ 瓦斯

Answer 1

我认为AVQueuePlayer（AVPlayer 的子类）正是从 iOS 4.1 开始完成这项工作（播放一系列项目）： http://developer.apple.com/library/ios/#documentation/AVFoundation/Reference/AVQueuePlayer_Class/Reference/Reference.html

我自己没有尝试过，但肯定会尝试一下。

Answer 2

每个声音使用一个 AVAudioPlayer。

Answer 3

嗯，您的代码示例对我来说不是开箱即用的。太棒了，我想我会用一个固定的版本来回应：

Looper.h：

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>

@interface Looper : NSObject <AVAudioPlayerDelegate> {
    AVAudioPlayer* player;
    NSArray* fileNameQueue;
    int index;
}

@property (nonatomic, retain) AVAudioPlayer* player;
@property (nonatomic, retain) NSArray* fileNameQueue;

- (id)initWithFileNameQueue:(NSArray*)queue;
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag;
- (void)play:(int)i;
- (void)stop;

@end

Looper.m：

#import "Looper.h"
@implementation Looper
@synthesize player, fileNameQueue;

- (id)initWithFileNameQueue:(NSArray*)queue {
    if ((self = [super init])) {
        self.fileNameQueue = queue;
        index = 0;
        [self play:index];
    }
    return self;
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {
    if (index < fileNameQueue.count) {
        [self play:index];
    } else {
        //reached end of queue
    }
}

- (void)play:(int)i {
    self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:[[NSURL alloc] initFileURLWithPath:[[NSBundle mainBundle] pathForResource:[fileNameQueue objectAtIndex:i] ofType:nil]] error:nil];
    [player release];
    player.delegate = self;
    [player prepareToPlay];
    [player play];    
    index++;
}

- (void)stop {
    if (self.player.playing) [player stop];
}

- (void)dealloc {
    self.fileNameQueue = nil;
    self.player = nil;        
    [super dealloc];
}

@end

我会这样称呼它：

 Looper * looper = [[Looper alloc] initWithFileNameQueue:[NSArray arrayWithObjects: audioFile, audioFile2, nil ]];

我在使用 Objective-C 开发 iPhone/iPad 方面只有一年多一点的经验，因此请随时提出更多批评意见。

Answer 4

我已经实现了一个类来处理这个问题。

要使用，只需执行以下操作：

[looper playAudioFiles:[NSArray arrayWithObjects:
    @"add.mp3",
    [NSString stringWithFormat:@"%d.mp3", numeral1.tag],
    @"and.mp3",
    [NSString stringWithFormat:@"%d.mp3", numeral2.tag],
    nil
]];

Looper.m

#import "Looper.h"
@implementation Looper
@synthesize player, fileNameQueue;

- (id)initWithFileNameQueue:(NSArray*)queue {
    if ((self = [super init])) {
        self.fileNameQueue = queue;
        index = 0;
        [self play:index];
    }
    return self;
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {
    if (index < fileNameQueue.count) {
        [self play:index];
    } else {
        //reached end of queue
    }
}

- (void)play:(int)i {
    self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:[[NSURL alloc] initFileURLWithPath:[[NSBundle mainBundle] pathForResource:[fileNameQueue objectAtIndex:i] ofType:nil]] error:nil];
    [player release];
    player.delegate = self;
    [player prepareToPlay];
    [player play];    
    index++;
}

- (void)stop {
    if (self.player.playing) [player stop];
}

- (void)dealloc {
    self.fileNameQueue = nil;
    self.player = nil;        
    [super dealloc];
}

@end

Looper.h

#import <Foundation/Foundation.h>


@interface Looper : NSObject <AVAudioPlayerDelegate> {
    AVAudioPlayer* player;
    NSArray* fileNameQueue;
    int index;
}

@property (nonatomic, retain) AVAudioPlayer* player;
@property (nonatomic, retain) NSArray* fileNameQueue;

- (id)initWithFileNameQueue:(NSArray*)queue;
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag;
- (void)play:(int)i;
- (void)stop;


@end

Answer 5

提前初始化、准备项目和排队是个好主意，例如在 viewDidLoad 方法上。

如果你正在使用 Swift，

    override func viewDidLoad() {
        super.viewDidLoad()
        let item0 = AVPlayerItem.init(URL: NSBundle.mainBundle().URLForResource("url", withExtension: "wav")!)

        let item1 = AVPlayerItem.init(URL: NSBundle.mainBundle().URLForResource("dog", withExtension: "aifc")!)
        let item2 = AVPlayerItem.init(URL: NSBundle.mainBundle().URLForResource("GreatJob", withExtension: "wav")!)


        let itemsToPlay:[AVPlayerItem] = [item0, item1, item2] 
        queuePlayer = AVQueuePlayer.init(items: itemsToPlay)
    }

然后当事件发生时，

 queuePlayer.play()

请注意，如果您使用队列，声音之间仍可能存在一些间隙。

您可以在问题How to do something when AVQueuePlayer finishes the last playeritem中找到Objective-C版本

希望对你有帮助。