AVFoundation 音乐播放器的 IOS 问题，50% 的时间都在工作

Posted 2023-03-08

【中文标题】AVFoundation 音乐播放器的 IOS 问题，50% 的时间都在工作

【英文标题】：IOS issues with AVFoundation music player, working 50% of the time

【发布时间】：2013-09-01 19:45:42

【问题描述】：

我在使用 AVFoundation 音乐播放器时遇到了一些问题。

1) 它不会立即启动，我猜模拟器上的缓冲很慢？

2）只有50%的时候有声音启动，另外50%不启动，非常不可靠

这是我的课

Music_Player.h

@interface Music_Player : NSObject <AVAudioPlayerDelegate>

@property (nonatomic, retain) AVAudioPlayer *audioPlayer;

@property (nonatomic, retain) NSString *trackPlaying;

@property (nonatomic) BOOL isPlaying;

@property (nonatomic, retain) NSTimer *timer;

@property (nonatomic, retain) UISlider *slider;

-(void)initTrack: (NSString *) track;

-(void)startPlayer;
-(void)pausePlayer;
-(void)stopPlayer;

-(void)sliderUp;
-(void)sliderDown;

@end

Music_Player.m

#import "Music Player.h"

@implementation Music_Player


@synthesize audioPlayer;

@synthesize trackPlaying;
@synthesize timer;

@synthesize isPlaying;

@synthesize slider;

-(void)initTrack:(NSString *)track

    /* Init slider */

    self.isPlaying = FALSE;
    self.trackPlaying = track;

    NSBundle *mainBundle = [NSBundle mainBundle];
    NSString *filePath = [mainBundle pathForResource:self.trackPlaying ofType:@"mp3"];
    NSData *fileData = [NSData dataWithContentsOfFile:filePath];

    NSError *error = nil;

    self.audioPlayer = [[AVAudioPlayer alloc] initWithData:fileData error:&error];
    [self.audioPlayer prepareToPlay];

    /* Set slider max value */
    self.slider.minimumValue = 0;
    self.slider.maximumValue = self.audioPlayer.duration - 5;


-(void)startPlayer

    if (self.isPlaying == TRUE)
    
        NSLog(@"Pause clicked");
        [self.audioPlayer pause];
        self.isPlaying = FALSE;

     else 
        NSLog(@"Play clicked");
        [self.audioPlayer play];
        self.isPlaying = TRUE;

        if (![self.timer isValid]) 
            self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateTime) userInfo:nil repeats:YES];
        
    


- (void)updateTime 

    if (self.isPlaying == TRUE) 

        NSTimeInterval currentTime = self.audioPlayer.currentTime;

        NSLog(@"%f", currentTime);
        // update UI with currentTime;
        slider.value = round(currentTime);
    


-(void)pausePlayer

    if (self.isPlaying == TRUE)
    
        [self.audioPlayer pause];
        self.isPlaying = FALSE;
    


-(void)stopPlayer

    if (self.isPlaying == TRUE)
    
        NSLog(@"Stop clicked");
        [self.audioPlayer stop];
        self.audioPlayer.currentTime = 0;
        self.slider.value = round(self.audioPlayer.currentTime);
        self.isPlaying = FALSE;
    


-(void)sliderUp

    if (self.isPlaying == FALSE)
    
        self.audioPlayer.currentTime = round(slider.value);
        [self.audioPlayer play];
        self.isPlaying = TRUE;
    


-(void)sliderDown

    if (self.isPlaying == TRUE)
    
        self.isPlaying = FALSE;
        [self.audioPlayer stop];
    


/* AUDIO PLAYER DELEGATES */

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag

    NSLog(@"Did finish with, %c", flag);


- (void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error

    NSLog(@"Error %@",error);


@end

我刚刚设置了滑块属性并使用我的 viewController 中的轨道对其进行了初始化

/* Init Music */
self.music_player = [[Music_Player alloc] init];
self.music_player.slider = self.slider;

[self.music_player initTrack:@"track1"];

然后我只是将 Btn 点击和滑块值更改传递给 music_player 类，可能是什么问题？我明天将在 iPhone 上测试它，所以它可能只是一个模拟器问题吗？

【参考方案1】：

两件事：

initWithData:error:中，调用后是否设置错误？

为什么不使用[AVAudioPlayer initWithContentsOfURL:error:]？例如：

- (void)initTrack:(NSString *)track

    self.isPlaying = NO;
    self.trackPlaying = track;

    NSBundle *mainBundle = ;
    NSString *filePath = [[NSBundle mainBundle] pathForResource:self.trackPlaying ofType:@"mp3"];
    NSURL *fileURL = [NSURL fileURLWithPath:filePath];

    NSError *error = nil;

    self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:fileURL error:&error];

【讨论】：

现在是，我只是设置了委托，但之前没有

那个方法根本找不到文件

对不起，我们应该在这里使用 fileURLWithPath:，而不是 URLWithString:。