详解iOS App中调用AVAudioPlayer播放音频文件的用法

要给工程中添加音频,首先要导入音频的框架 avfoundation.framework

然后新建一个类继承于uiviewcontroller, 我这里就叫firstvc.
首先在 appdelegate.m中初始化根视图

#import "appdelegate.h"
#import "firstvc.h"
@implementation appdelegate

- (void)dealloc
{
    [_window release];
    [super dealloc];
}

- (bool)application:(uiapplication *)application didfinishlaunchingwithoptions:(nsdictionary *)launchoptions
{
    self.window = [[[uiwindow alloc] initwithframe:[[uiscreen mainscreen] bounds]] autorelease];
    // override point for customization after application launch.
   
    firstvc *firstvc = [[firstvc alloc] init];
    self.window.rootviewcontroller = firstvc;
    [firstvc release];
   
    self.window.backgroundcolor = [uicolor whitecolor];
    [self.window makekeyandvisible];
    return yes;
}

然后在firstvc.h中导入avfoundation框架 

#import <uikit/uikit.h>

//要想使用封装好的音频类,导入框,导入类头文件,缺一不可;
#import <avfoundation/avfoundation.h>

@interface firstvc : uiviewcontroller<avaudioplayerdelegate>
{
    avaudioplayer *avaudioplayer;   //播放器player
    uiprogressview *progressv;      //播放进度
    uislider *volumeslider;         //声音控制
    nstimer *timer;                 //监控音频播放进度
}

@end

然后在firstvc.m里的viewdidload方法里填写代码   你需要导入一个音频才可以播放 像添加图片一样,直接拖到工程里就可以了

- (void)viewdidload
{
    [super viewdidload];
    // do any additional setup after loading the view.
    //初始化三个button
    uibutton *button = [uibutton buttonwithtype:uibuttontyperoundedrect];
    [button setframe:cgrectmake(100, 100, 60, 40)];
    [button settitle:@"play" forstate:uicontrolstatenormal];
    [button addtarget:self action:@selector(play) forcontrolevents:uicontroleventtouchupinside];
    [self.view addsubview:button];
   
    uibutton *button1 = [uibutton buttonwithtype:uibuttontyperoundedrect];
    [button1 setframe:cgrectmake(100, 150, 60, 40)];
    [button1 settitle:@"pause" forstate:uicontrolstatenormal];
    [button1 addtarget:self action:@selector(pause) forcontrolevents:uicontroleventtouchupinside];
    [self.view addsubview:button1];
   
    uibutton *button2 = [uibutton buttonwithtype:uibuttontyperoundedrect];
    [button2 setframe:cgrectmake(100, 200, 60, 40)];
    [button2 settitle:@"stop" forstate:uicontrolstatenormal];
    [button2 addtarget:self action:@selector(stop) forcontrolevents:uicontroleventtouchupinside];
    [self.view addsubview:button2];
   
    //从budle路径下读取音频文件　　轻音乐 - 萨克斯回家 这个文件名是你的歌曲名字,mp3是你的音频格式
    nsstring *string = [[nsbundle mainbundle] pathforresource:@"轻音乐 - 萨克斯回家" oftype:@"mp3"];
    //把音频文件转换成url格式
    nsurl *url = [nsurl fileurlwithpath:string];
    //初始化音频类 并且添加播放文件
    avaudioplayer = [[avaudioplayer alloc] initwithcontentsofurl:url error:nil];
    //设置代理
    avaudioplayer.delegate = self;
   
    //设置初始音量大小
   // avaudioplayer.volume = 1;
   
    //设置音乐播放次数  -1为一直循环
    avaudioplayer.numberofloops = -1;
   
    //预播放
    [avaudioplayer preparetoplay];
   
    //初始化一个播放进度条
    progressv = [[uiprogressview alloc] initwithframe:cgrectmake(20, 50, 200, 20)];
    [self.view addsubview:progressv];
    [progressv release];
   
    //用nstimer来监控音频播放进度
    timer = [nstimer scheduledtimerwithtimeinterval:0.1 target:self
                                                     selector:@selector(playprogress)
                                                     userinfo:nil repeats:yes];
    //初始化音量控制
    volumeslider = [[uislider alloc] initwithframe:cgrectmake(20, 70, 200, 20)];
    [volumeslider addtarget:self action:@selector(volumechange)
                       forcontrolevents:uicontroleventvaluechanged];
    //设置最小音量
    volumeslider.minimumvalue = 0.0f;
    //设置最大音量
    volumeslider.maximumvalue = 10.0f;
    //初始化音量为多少
    volumeslider.value = 5.0f;
   
    [self.view addsubview:volumeslider];
    [volumeslider release];

    //声音开关控件(静音)
    uiswitch *swith = [[uiswitch alloc] initwithframe:cgrectmake(100, 20, 60, 40)];
    [swith addtarget:self action:@selector(onoroff:) forcontrolevents:uicontroleventvaluechanged];
    //默认状态为打开
    swith.on = yes;
    [self.view addsubview:swith];
    [swith  release];
}

相应的自定义方法代码如下

//播放
- (void)play
{ 
    [avaudioplayer play];
}
    //暂停
- (void)pause
{
    [avaudioplayer pause];
}
    //停止
- (void)stop
{
    avaudioplayer.currenttime = 0;  //当前播放时间设置为0
    [avaudioplayer stop];
}
//播放进度条
- (void)playprogress
{
    //通过音频播放时长的百分比,给progressview进行赋值;
    progressv.progress = avaudioplayer.currenttime/avaudioplayer.duration;
}
//声音开关(是否静音)
- (void)onoroff:(uiswitch *)sender
{
    avaudioplayer.volume = sender.on;
}

//播放音量控制
- (void)volumechange
{
   avaudioplayer.volume = volumeslider.value;
}

//播放完成时调用的方法  (代理里的方法),需要设置代理才可以调用
- (void)audioplayerdidfinishplaying:(avaudioplayer *)player successfully:(bool)flag
{
    [timer invalidate]; //nstimer暂停   invalidate  使...无效;
}

最后别忘了释放内存

- (void)dealloc
{
    [avaudioplayer release];
    [progressv release];
    [volumeslider release];
    [timer release];
    [super dealloc];
}

当然,你也可以再定义一个uislider来控制播放进度.

最后运行起来的就是这个样子

如果想要播放网络音乐，那么遗憾的是ios中的avaudioplayer不支持边下边播，所以只能下载到本地再播放。
方法：

nsstring *urlstr = @"http://…………xxx.mp3"; 
nsurl *url = [[nsurl alloc]initwithstring:urlstr]; 
nsdata * audiodata = [nsdata datawithcontentsofurl:url]; 
 
//将数据保存到本地指定位置          
nsstring *docdirpath = [nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes) objectatindex:0]; 
nsstring *filepath = [nsstring stringwithformat:@"%@/%@.mp3", docdirpath , @"temp"]; 
[audiodata writetofile:filepath atomically:yes]; 
       
//播放本地音乐           
nsurl *fileurl = [nsurl fileurlwithpath:filepath]; 
player = [[avaudioplayer alloc] initwithcontentsofurl:fileurl error:nil]; 
[player play];

注意代码中的player是类的私有变量，因为在arc模式下如果定义局部变量，出了作用域后对象会被销毁。这个问题也是纠结了好久才搞明白。参见链接
当然也可以不保存文件，只是将player的构造方法改为用data实例化即可。

总结：
下面说一下我遇到的各种问题：
1、由于添加了all exception断点，导致每次都在初始化的时候自动断到，因为不是oc异常，又无异常信息显示。这时应该编辑断点，将其类型由all改为oc。这个异常并不会导致程序的崩溃，所以可以不作处理。
2、网上有的说不能播放，解决方案是应该在 appdelegate.m文件中的
application  didfinishlaunchingwithoptions 添加这样一句代码：

[[avaudiosession sharedinstance]setcategory:avaudiosessioncategoryplaybackerror:nil];