android框架_5.0的AudioManager分析_013

AudioManager分析

一、AudioManager类

１、frameworks/base/media/java/android/media/AudioManager.java

该类主要是用于上层应用的API接口与frameworks的逻辑交互工作，这里有很多的功能设置选项；

AudioManager类位于android.Media 包中，该类提供访问控制音量和钤声模式的操作。

通过getSystemService(Context.AUDIO_SERVICE)方法获得AudioManager实例对象。

AudioManager audiomanage = (AudioManager)context.getSystemService(Context.AUDIO_SERVICE);

audiomanager就是我们定义的控制系统声音的对象。

/**  * AudioManager provides access to volume and ringer mode control.  * <p>  * Use <code>Context.getSystemService(Context.AUDIO_SERVICE)</code> to get  * an instance of this class.  */ public class AudioManager {      private final Context mContext;     private long mVolumeKeyUpTime;     private final boolean mUseMasterVolume;　//从config.xml文件中获取，默认为false     private final boolean mUseVolumeKeySounds;//从config.xml文件中获取，默认为true;     private final boolean mUseFixedVolume; //从config.xml文件中获取，默认为false;     private final Binder mToken = new Binder();//默认还没有用这个对象，     private static String TAG = "AudioManager";     private static final AudioPortEventHandler sAudioPortEventHandler = new AudioPortEventHandler();

２、初始化变量：

    /**      * @hide      */     public AudioManager(Context context) {         mContext = context;         mUseMasterVolume = mContext.getResources().getBoolean(                 com.android.internal.R.bool.config_useMasterVolume);         mUseVolumeKeySounds = mContext.getResources().getBoolean(                 com.android.internal.R.bool.config_useVolumeKeySounds);         mUseFixedVolume = mContext.getResources().getBoolean(                 com.android.internal.R.bool.config_useFixedVolume);         sAudioPortEventHandler.init();     }      private static IAudioService getService()     {         if (sService != null) {             return sService;         }         IBinder b = ServiceManager.getService(Context.AUDIO_SERVICE);         sService = IAudioService.Stub.asInterface(b);         return sService;     }

３、从配置文件中获取属性值，和初始化对象；同时获取一个IBinder的服务对象；

文章来源: android框架_5.0的AudioManager分析_013