多媒体之音乐播放

音效是比较简短的,音乐比较长,格式比较多,那就需要使用<AVFoundation/AVFoundation.h>框架，AVAudioPlayer只支持本地的

//
//  ViewController.m
//  AVFoundation
//
//  Created by City--Online on 15/5/5.
//  Copyright (c) 2015年 CYW. All rights reserved.
//

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>

@interface ViewController ()<AVAudioPlayerDelegate>
@property(nonatomic,strong)AVAudioPlayer *audioPlayer;
@property(nonatomic,strong)UIButton *btnStop;
@property(nonatomic,strong)UIButton *btnPause;
@property(nonatomic,strong) UIButton *btnPlayer;
@property(nonatomic,strong)UIProgressView *progress;
@property(nonatomic,strong)UIProgressView *averagePowerProgress;
@property(nonatomic,weak)NSTimer *timer;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self stepUI];

    NSString *path=[[NSBundle mainBundle]pathForResource:@"1" ofType:@".mp3"];
    NSURL *url=[[NSURL alloc]initFileURLWithPath:path];
    _audioPlayer=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:nil];
    //立体声平衡 －1 左声道  0 左右声道平衡  1右声道
    _audioPlayer.pan=1.0;
    //音量(0-1)
    _audioPlayer.volume=0.8;
    //是否允许改变速率
    _audioPlayer.enableRate=YES;
    //播放速率 (0.5-2) 1.0正常播放
    _audioPlayer.rate=0.8;
    //是否启用音频测量 默认NO
    _audioPlayer.meteringEnabled=true;
    //循环次数
    _audioPlayer.numberOfLoops=3;
    //设置代理
    _audioPlayer.delegate=self;

}
-(void)stepUI
{
    // 进度条
   _progress=[[UIProgressView alloc]initWithFrame:CGRectMake(100, 100, 200, 10)];
    [self.view addSubview:_progress];

    _averagePowerProgress=[[UIProgressView alloc]initWithFrame:CGRectMake(100,  200, 100, 10)];
    [self.view addSubview:_averagePowerProgress];

    //停止播放
    _btnStop=[UIButton buttonWithType:UIButtonTypeSystem];
    [_btnStop setTitle:@"停止" forState:UIControlStateNormal];
    _btnStop.frame=CGRectMake(40, 150, 40, 40);
    _btnStop.tag=1001;
    [_btnStop addTarget:self action:@selector(operation:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btnStop];

    //播放
    _btnPlayer=[UIButton buttonWithType:UIButtonTypeSystem];
    [_btnPlayer setTitle:@"播放" forState:UIControlStateNormal];
    _btnPlayer.frame=CGRectMake(90, 150, 40, 40);
    _btnPlayer.tag=1002;
    [_btnPlayer addTarget:self action:@selector(operation:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btnPlayer];

    _btnPause=[UIButton buttonWithType:UIButtonTypeSystem];
    [_btnPause setTitle:@"暂停" forState:UIControlStateNormal];
    _btnPause.frame=CGRectMake(140, 150, 40, 40);
    _btnPause.tag=1003;
    [_btnPause addTarget:self action:@selector(operation:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_btnPause];

    _timer=[NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(updateProgress) userInfo:nil repeats:YES];

}
-(void)operation:(id)sender
{
    UIButton *btn=(UIButton *)sender;
    switch (btn.tag) {
        case 1001:
            if ([_audioPlayer isPlaying]) {
                [_audioPlayer stop];
                [_progress setProgress:0];
                //
                 _timer.fireDate=[NSDate distantFuture];
                _audioPlayer.currentTime=0;

                NSLog(@"%ld",_audioPlayer.numberOfChannels);
            }
            break;
        case 1002:
            if (![_audioPlayer isPlaying]) {
                [_audioPlayer play];
                //恢复定时
                _timer.fireDate=[NSDate distantPast];
            }
            break;
        case 1003:
            if ([_audioPlayer isPlaying]) {
                [_audioPlayer pause];
                //暂停定时器，注意不能调用invalidate方法，此方法会取消，之后无法恢复
                _timer.fireDate=[NSDate distantFuture];
            }
            break;

        default:
            break;
    }

}
-(void)updateProgress
{
    float progress=_audioPlayer.currentTime/_audioPlayer.duration;
    [_progress setProgress:progress animated:YES];
    //更新音频测量值，注意如果要更新音频测量值必须设置meteringEnabled为YES，通过音频测量值可以即时获得音频分贝等信息
    [_audioPlayer updateMeters];
    //获得指定声道的分贝峰值，注意如果要获得分贝峰值必须在此之前调用updateMeters方法
//   float  peakPower=[_audioPlayer peakPowerForChannel:2];
//    NSLog(@"%lf",peakPower);
    //获得指定声道的分贝平均值，注意如果要获得分贝平均值必须在此之前调用updateMeters方法
   float averagePower= [_audioPlayer averagePowerForChannel:1];
    //类似上下波动
    [_averagePowerProgress setProgress:(-averagePower)/50.0 animated:YES];
    NSLog(@"%lf",averagePower);

}

-(void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVAudioSessionRouteChangeNotification object:nil];
}
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag;
{
    NSLog(@"播放完毕");
}

- (void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error
{
     NSLog(@"%@",error);
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

上面的是进度条，下面的是分贝平均值，类似有的音乐播放器波浪效果