【iOS开发-118】AVFoundation框架：AudioServices...音效，AVAudioPlayer音乐，AVAudioRecord录音

（1）音效播放，核心代码，主要是创建一个播放器，然后播放。

#import "WPSound.h"#import <AVFoundation/AVFoundation.h>@implementation WPSoundstatic NSMutableDictionary *_soundIDDict;+(void)initialize{    _soundIDDict=[NSMutableDictionary dictionary];}//不能用懒加载，因为给用户使用的时类方法，所以需要在上面的类初始化中设置//-(NSMutableDictionary *)soundIDDict{//    if (_soundIDDict==nil) {//        _soundIDDict=[NSMutableDictionary dictionary];//    }//    return _soundIDDict;//}+(void)soundPlay:(NSString *)fileName{    if (!fileName) return;    //取出soundID    SystemSoundID soundID=[_soundIDDict[fileName] unsignedIntValue];    if (!soundID) {        NSURL *url=[[NSBundle mainBundle]URLForResource:fileName withExtension:nil];        if (!url) return;        AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &soundID);        //放入字典        _soundIDDict[fileName]=@(soundID);    }    AudioServicesPlaySystemSound(soundID);}+(void)soundDispose:(NSString *)fileName{    if (fileName) return;    SystemSoundID soundID=[_soundIDDict[fileName] unsignedIntValue];    if (!soundID) return;    AudioServicesDisposeSystemSoundID(soundID);    //从字典中移除    [_soundIDDict removeObjectForKey:fileName];}@end

（2）音乐播放，核心代码。需要注意的是创建的播放器需要是全局变量。

#import "MusicTool.h"@implementation MusicToolstatic NSMutableDictionary *_audioPlayerDict;static AVAudioPlayer *_audioPlayer;+(void)initialize{    _audioPlayerDict=[NSMutableDictionary dictionary];    //设置会话类型    AVAudioSession *session=[AVAudioSession sharedInstance];    [session setCategory:AVAudioSessionCategorySoloAmbient error:nil];    [session setActive:YES error:nil];}+(AVAudioPlayer *)musicPlay:(NSString *)fileName{    if (!fileName) return nil;    //取出播放器    AVAudioPlayer *audioPlayer=_audioPlayerDict[fileName];    if (!audioPlayer) {        NSURL *url=[[NSBundle mainBundle]URLForResource:fileName withExtension:nil];        if (!url) return nil;        //创建audioPlayer        AVAudioPlayer *audioPlayer=[[AVAudioPlayer alloc]initWithContentsOfURL:url error:NULL];        _audioPlayer=audioPlayer;        [_audioPlayer prepareToPlay];        _audioPlayer.enableRate=YES;        //以下设置播放速度，可以测试用//        _audioPlayer.rate=10;//        _audioPlayerDict[fileName]=audioPlayer;    }    if (!_audioPlayer.isPlaying) {        [_audioPlayer play];    }    return _audioPlayer;}+(void)musicPause:(NSString *)fileName{    if (!fileName) return;    AVAudioPlayer *audioPlayer=_audioPlayerDict[fileName];    if (audioPlayer.isPlaying) {        [audioPlayer pause];    }}+(void)musicStop:(NSString *)fileName{    if (!fileName) return;    AVAudioPlayer *audioPlayer=_audioPlayerDict[fileName];    if (audioPlayer.isPlaying) {        [audioPlayer stop];        [_audioPlayerDict removeObjectForKey:fileName];    }}+(AVAudioPlayer *)currentPlayingAudioPlayer{    for (NSString *fileName in _audioPlayerDict) {        AVAudioPlayer *audioPlayer=_audioPlayerDict[fileName];        if (audioPlayer.isPlaying) {            return audioPlayer;        }    }    return nil;}@end

（3）录音，核心代码。

#import "ViewController.h"#import <AVFoundation/AVFoundation.h>@interface ViewController ()@property(nonatomic,strong) AVAudioRecorder *recorder;@property(nonatomic,strong) CADisplayLink *link;@property(nonatomic,assign) float silentDuration;- (IBAction)recordStart:(id)sender;- (IBAction)recordStop:(id)sender;@end@implementation ViewController-(CADisplayLink *)link{    if (_link==nil) {        _link=[CADisplayLink displayLinkWithTarget:self selector:@selector(update)];    }    return _link;}-(void)update{    //更新录音器的测量值    [self.recorder updateMeters];    //获得平均分贝    float power=[self.recorder averagePowerForChannel:0];        if (power<-30) {        self.silentDuration+=self.link.duration;        if (self.silentDuration>=2) {            [self.recorder stop];            [self.link invalidate];            self.link=nil;        }    }else{        self.silentDuration=0;    }}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (IBAction)recordStart:(id)sender {    NSString *path=[[NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"test.caf"];    NSURL *url=[NSURL fileURLWithPath:path];    NSMutableDictionary *setting=[NSMutableDictionary dictionary];    //音频格式    setting[AVFormatIDKey]=@(kAudioFormatAppleIMA4);    //音频采样率    setting[AVSampleRateKey]=@(8000.0);    //音频通道数    setting[AVNumberOfChannelsKey]=@(1);    //线性音频位深度    setting[AVLinearPCMBitDepthKey]=@(8);        AVAudioRecorder *recorder=[[AVAudioRecorder alloc]initWithURL:url settings:setting error:nil];        //允许测量分贝    recorder.meteringEnabled=YES;        //缓冲    [recorder prepareToRecord];    //录音    [recorder record];        self.recorder=recorder;        //开启定时器    self.silentDuration=0;    [self.link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];}- (IBAction)recordStop:(id)sender {    [self.link invalidate];    self.link=nil;    [self.recorder stop];}@end

（3）后台播放音乐，设置3处地方。

——在AppDelegate.m中设置

- (void)applicationDidEnterBackground:(UIApplication *)application {    [application beginBackgroundTaskWithExpirationHandler:nil];}

——在info.plist中设置

——还有一个在程序中设置音频会话类型（可省略）

+(void)initialize{    _audioPlayerDict=[NSMutableDictionary dictionary];    //设置会话类型    AVAudioSession *session=[AVAudioSession sharedInstance];    [session setCategory:AVAudioSessionCategorySoloAmbient error:nil];    [session setActive:YES error:nil];}