iOS播放MP3音频

1.新建single view工程，导入AVFoundation库

2.ViewController.xib如图

3.ViewController.h文件

# import <uikit uikit.h= "" >
# import

@interface ViewController : UIViewController {
    //进度
    IBOutlet UISlider *_proSlider;
    //声道
    IBOutlet UISlider *_panSlider;
    //速度
    IBOutlet UISlider *_speedSlider;
    //音量
    IBOutlet UISlider *_volSlider;
    IBOutlet UIProgressView *_proV;
    IBOutlet UIProgressView *_proV2;

    AVAudioPlayer *_player;

    NSTimer *_timer;
}

- (IBAction)proSlider:(id)sender;
- (IBAction)panSlider:(id)sender;
- (IBAction)speedSlider:(id)sender;
- (IBAction)volSlider:(id)sender;

- (IBAction)play:(id)sender;
- (IBAction)pause:(id)sender;

@end </avfoundation></uikit>

4.ViewController.m文件

# import "ViewController.h"

@implementation ViewController

- ( void )viewDidLoad
{
    [ super viewDidLoad];

    NSString *path = [[NSBundle mainBundle] pathForResource:@ "Beat It" ofType:@ "mp3" ];
//    NSURL *url = [NSURL URLWithString:path];//不能这样写，因为是本地路径
    NSURL *url = [NSURL fileURLWithPath:path]; //本地路径应该这样写

    _player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];
    //触发play事件的时候会将mp3文件加载到内存中，然后再播放，所以开始的时候可能按按钮的时候会卡，所以需要prepare
    [_player prepareToPlay];
    //设置支持变速
    _player.enableRate = YES;
    //峰值和平均值
    _player.meteringEnabled = YES;

}

- ( void )play:(id)sender
{
    //按播放，开始定时器
    _timer = [NSTimer scheduledTimerWithTimeInterval: 0.1 target:self selector: @selector (refresh) userInfo:nil repeats:YES];
    [_player play];
}

- ( void )pause:(id)sender
{
    [_player pause];
    //定时器失效
    [_timer invalidate];
}

- ( void )refresh
{
    //每隔0.1秒刷新一次进度,当前时间/总时间
    float pro = _player.currentTime/_player.duration;
    [_proSlider setValue:pro animated:YES];

    //averagePowerForChannel和peakPowerForChannel的属性分别为声音的最高振幅和平均振幅
    [_player updateMeters]; //不刷新就永远是0
    float pead = ([_player peakPowerForChannel: 0 ]+ 50 )/ 50 ; //0左声道,1右声道
    float ave = ([_player averagePowerForChannel: 0 ]+ 50 )/ 50 ; //同上
    [_proV setProgress:pead animated:YES];
    [_proV2 setProgress:ave animated:YES];
}

//进度
- (IBAction)proSlider:(id)sender
{
    //当前时间=总时间*slider.value;
    float curTime = _player.duration*_proSlider.value;
    [_player setCurrentTime:curTime];
}
//声道
- (IBAction)panSlider:(id)sender
{
    _player.pan = _panSlider.value;
}
//速度
- (IBAction)speedSlider:(id)sender
{
    _player.rate = _speedSlider.value;
}
//音量
- (IBAction)volSlider:(id)sender
{
    _player.volume = _volSlider.value;
}

@end