上一章我们了解了FM主activity：FMRadio.java，若没查看的，请打开链接Android FM模块学习之四源码解析（一）
查看fmradio.java源码注释。接下来我们来看看FM重要的一个类：FMRadioService.java
由上一章我们已经知道，打开FM时，在OnStart函数中会bindToService来开启服务，
public boolean bindToService(Context context, ServiceConnection callback) {
Log.e(LOGTAG, "bindToService: Context with serviceconnection callback");
context.startService(new Intent(context, FMRadioService.class));
ServiceBinder sb = new ServiceBinder(callback);
sConnectionMap.put(context, sb);
return context.bindService((new Intent()).setClass(context,
FMRadioService.class), sb, 0);
}
开启了服务，就会去做一些FM的操作和响应。我们进入到类FMRadioSerivce.java中
在publicvoid onCreate() 方法里初始化数据
mPrefs = new FmSharedPreferences(this);初始化存取数据
电话监听
TelephonyManager tmgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
tmgr.listen(mPhoneStateListener, PhoneStateListener.LISTEN_CALL_STATE |
PhoneStateListener.LISTEN_DATA_ACTIVITY);
保持CPU 运转，屏幕和键盘灯有可能是关闭的
PowerManager pm = (PowerManager)getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, this.getClass().getName());
mWakeLock.setReferenceCounted(false);
注册屏幕是否开启
registerScreenOnOffListener();
注册耳机
registerHeadsetListener();
registerSleepExpired();
registerRecordTimeout();
registerDelayedServiceStop();
registerFMRecordingStatus();
Activity销毁界面方法
public void onDestroy()
在onDestroy方法里mDelayedStopHandler.removeCallbacksAndMessages(null); 移除回调handler信息
关闭警铃cancelAlarms()
将声音设为音乐焦点
//release the audio focus listener
AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
if (isMuted()) {
mMuted = false;
audioManager.setStreamMute(AudioManager.STREAM_MUSIC,false);
}
audioManager.abandonAudioFocus(mAudioFocusListener);
遗弃音频管理监听
audioManager.abandonAudioFocus(mAudioFocusListener);
在onDestroy方法里卸载注册
/* Remove the Screen On/off listener */
if (mScreenOnOffReceiver != null) {
unregisterReceiver(mScreenOnOffReceiver);
mScreenOnOffReceiver = null;
}
/* Unregister the headset Broadcase receiver */
if (mAirplaneModeReceiver != null) {
unregisterReceiver(mAirplaneModeReceiver);
mAirplaneModeReceiver = null;
}
if (mHeadsetReceiver != null) {unregisterReceiver(mHeadsetReceiver);
mHeadsetReceiver = null;
}
if( mMusicCommandListener != null ) {
unregisterReceiver(mMusicCommandListener);
mMusicCommandListener = null;
}
if( mFmMediaButtonListener != null ) {
unregisterReceiver(mFmMediaButtonListener);
mFmMediaButtonListener = null;
} if (mAudioBecomeNoisyListener != null) {
unregisterReceiver(mAudioBecomeNoisyListener);
mAudioBecomeNoisyListener = null;
}
if (mSleepExpiredListener != null ) {
unregisterReceiver(mSleepExpiredListener);
mSleepExpiredListener = null;
}
if (mRecordTimeoutListener != null) {
unregisterReceiver(mRecordTimeoutListener);
mRecordTimeoutListener = null;
} if (mDelayedServiceStopListener != null) {
unregisterReceiver(mDelayedServiceStopListener);
mDelayedServiceStopListener = null;
}
if (mFmRecordingStatus != null ) {
unregisterReceiver(mFmRecordingStatus);
mFmRecordingStatus = null;
}
关闭收音机fmOff();关掉调频:禁用调频主机和硬件。
TelephonyManager tmgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
tmgr.listen(mPhoneStateListener, 0);
Log.d(LOGTAG, "onDestroy: unbindFromService completed");
//unregisterReceiver(mIntentReceiver);
mWakeLock.release();
mWakeLock.release();<span style="font-family:KaiTi_GB2312;"> </span>释放唤醒锁
在onDestroy方法里设置电话监听参数0失去监听来电状态
tmgr.listen(mPhoneStateListener, 0);
public void registerFMRecordingStatus()控制
private void stop() 卸载FMMediaButtonIntentReceiver类的注册
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
ComponentName fmRadio = new ComponentName(this.getPackageName(),
FMMediaButtonIntentReceiver.class.getName());
mAudioManager.unregisterMediaButtonEventReceiver(fmRadio);
stop()方法调用gotoIdleState()方法删除mDelayedStopHandler空消息，关闭警铃
private void gotoIdleState()
mDelayedStopHandler.removeCallbacksAndMessages(null);
cancelAlarms();
setAlarmDelayedServiceStop();
stopForeground(true);
public IBinder onBind(Intent intent)绑定service
mDelayedStopHandler.removeCallbacksAndMessages(null);
cancelAlarms();关闭，警铃
mServiceInUse = true; 服务可以使用
/* Application/UI is attached, so get out of lower power mode */
setLowPowerMode(false);
public void onRebind(Intent intent)重新捆绑service
public void onStart(Intent intent, intstartId) StartService启动方法
public boolean onUnbind(Intent intent) 解绑service
获得进程名字方法private String getProcessName()
private void sendRecordIntent(int action) 发送录音无序广播在注册录音广播接收方法中
private void sendRecordServiceIntent(intaction) 发送录音状态无序广播
private void startFM()启动FM方法：
if(true == mAppShutdown) { // not to sendintent to AudioManager in Shutdown
if (isCallActive()) { // when Call is activenever let audio playback
if ( true == mPlaybackInProgress ) // no needto resend event
请求音频声音焦点
AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
int granted = audioManager.requestAudioFocus(mAudioFocusListener,AudioManager.STREAM_MUSIC,
AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
判断是否请求声音焦点成功
if(granted !=AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
Log.d(LOGTAG, "audio focuss couldnot be granted");
return;
}
/**
*请求改变焦点失败
*/
public static final int AUDIOFOCUS_REQUEST_FAILED = 0;
/**
*请求改变焦点成功 */
public static final intAUDIOFOCUS_REQUEST_GRANTED = 1;
实现audioManager类的焦点监听接口
private OnAudioFocusChangeListener mAudioFocusListener = new OnAudioFocusChangeListener() {
public void onAudioFocusChange(int focusChange) {
mDelayedStopHandler.obtainMessage(FOCUSCHANGE, focusChange, 0).sendToTarget();
}
};
请求声音焦点当music响起fm短时间暂停，music关闭后fm继续播放private void requestFocus()
mAudioManager.registerMediaButtonEventReceiver(fmRadio);注册多媒体按钮事件监听
mStoppedOnFocusLoss = false;停止声音焦值为false
停止fm使用
private void stopFM(){
AudioSystem.setDeviceConnectionState(AudioSystem.DEVICE_OUT_FM,AudioSystem.DEVICE_STATE_UNAVAILABLE,"");
}
重新设置fm
private void resetFM() {
AudioSystem.setDeviceConnectionState(AudioSystem.DEVICE_OUT_FM,
AudioSystem.DEVICE_STATE_UNAVAILABLE, "")
}
mA2dpDeviceState.isDeviceAvailable()蓝牙耳机设备可用是否可用
mOverA2DP全局变量是用来表示蓝牙是否可用
public boolean mute()静音模式 mMute 全局变量作为是否开启静音模式做判断
AudioManager audioManager =(AudioManager) getSystemService(Context.AUDIO_SERVICE);
设置静音audioManager.setStreamMute(AudioManager.STREAM_MUSIC,false);
public booleanisWiredHeadsetAvailable()耳机可用
public boolean isCallActive()通话中，调用getCallState()方法返回0为空闲没有通话，返回1是通话状态。
public void stopRecording()停止录音
private void fmActionOnCallState(int state ) 通话活动状态在进入fm方法privateboolean fmOn()中调用此方法，会用到通话监听获取state值。
public boolean startA2dpPlayback()启动蓝牙播放方法，
final Runnable mHeadsetPluginHandler= new Runnable()方法当耳机被拔出就关闭fm
final Runnable mHeadsetPluginHandler = new Runnable() {
public void run() {
/* Update the UI based on the state change of the headset/antenna*/
if(!isAntennaAvailable())
{
// if (!isFmOn())
// return;
/* Disable FM and let the UI know */
fmOff();
try
{
/* Notify the UI/Activity, only if the service is "bound"
by an activity and if Callbacks are registered
*/
if((mServiceInUse) && (mCallbacks != null) )
{
mCallbacks.onDisabled();
}
} catch (RemoteException e)
{
e.printStackTrace();
}
}else
{
/* headset is plugged back in,
So turn on FM if:
- FM is not already ON.
- If the FM UI/Activity is in the foreground
(the service is "bound" by an activity
and if Callbacks are registered)
*/
if ((!isFmOn()) && (mServiceInUse)
&& (mCallbacks != null))
{
if( true != fmOn() ) {
return;
}
try
{
mCallbacks.onEnabled();
} catch (RemoteException e)
{
e.printStackTrace();
}
}
}
}
};
public void clearStationInfo()清除fm状态信息
FmRxEvCallbacksAdaptor fmCallbacks= new FmRxEvCallbacksAdaptor() 广播接收类详解
public void FmRxEvEnableReceiver()可用接收
public voidFmRxEvDisableReceiver() 失去接收功能
public void FmRxEvRadioReset()收音机从新设置
调整fm频率并保持
FmSharedPreferences.setTunedFrequency(frequency);
mPrefs.Save();
enableStereo(FmSharedPreferences.getAudioOutputMode());获取立体声音是否可用
更新状态栏的通知信息
startNotification();设计fm在后台播放，service不被杀死，挂一个前台通知，在停止FMRadioService停止前台通知:
startForeground(FMRADIOSERVICE_STATUS,status);
在gotoIdleState()转到fm空闲状态的时候就停止前警铃，后警铃后台服务，前台通知栏等关闭。
mDelayedStopHandler.removeCallbacksAndMessages(null);
cancelAlarms();
setAlarmDelayedServiceStop();
stopForeground(true);
readInternalAntennaAvailable() 读的调频的内部天线可用状态
private booleansetAudioPath(boolean analogMode) 安装判断铃声路径
/*
*打开调频:调频硬件启动,并初始化调频模块
* @return返回值为真：如果调频使api调用成功,
假：如果api失败了。
* /
private boolean fmOn()
mReceiver = newFmReceiver(FMRADIO_DEVICE_FD_STRING, fmCallbacks);
从调频堆栈接收回调函数
FmRxEvCallbacksAdaptor fmCallbacks = newFmRxEvCallbacksAdaptor()
mReceiver.setRawRdsGrpMask();
FmSharedPreferences.clearTags();清除Tag
Fm重新设置
public void FmRxEvRadioReset()
fmRadioReset();
调整屏幕状态
public void FmRxEvRadioTuneStatus(intfrequency)
FmSharedPreferences.setTunedFrequency(frequency);
mPrefs.Save();
清除状态信息
if(mReceiver != null) {
clearStationInfo();
}
更新状态栏通知
startNotification();
判断RDSS支持
public void FmRxEvRdsLockStatus(booleanbRDSSupported)
mCallbacks.onStationRDSSupported(bRDSSupported);
更新警铃立体声状态
public void FmRxEvStereoStatus(booleanstereo)
mCallbacks.onAudioUpdate(stereo);
public void FmRxEvServiceAvailable(booleansignal)
fm搜索完成
public void FmRxEvSearchComplete(intfrequency)
FmSharedPreferences.setTunedFrequency(frequency);
clearStationInfo();
startNotification();
mWakeLock.acquire(10*1000);唤醒锁屏超时10*1000就释放唤醒对象
电话不是在空闲状态换回false
if ( TelephonyManager.CALL_STATE_IDLE !=getCallState() ) {
return bStatus;
}
正常进入fm
if (isFmOn())
{
/* FM Is already on,*/
bStatus = true;
Log.d(LOGTAG, "mReceiver.already enabled");
}
获取fm配置
FmConfig config =FmSharedPreferences.getFMConfiguration();
广播接收获取FM配置状态
bStatus =mReceiver.enable(FmSharedPreferences.getFMConfiguration());
扬声器可用设置boolean值
if (isSpeakerEnabled()) {
setAudioPath(false);
} else {
setAudioPath(true);
}
真正启动fm播放声音是AudioSystem.setDeviceConnectionState(); 设置fm设备启动，设置fm耳机播放还是扬声器播放(核心代码)
AudioSystem.setDeviceConnectionState(AudioSystem.DEVICE_OUT_FM,
AudioSystem.DEVICE_STATE_AVAILABLE, "");
if (isSpeakerEnabled()) {
mSpeakerPhoneOn = true;
Log.d(LOGTAG, "Audio source set it as speaker");
AudioSystem.setForceUse(AudioSystem.FOR_MEDIA, AudioSystem.FORCE_SPEAKER);
} else {
Log.d(LOGTAG, "Audio source set it as headset");
AudioSystem.setForceUse(AudioSystem.FOR_MEDIA, AudioSystem.FORCE_NONE);
}
audio焦点监听事件
AudioManager.OnAudioFocusChangeListener是申请成功之后监听AudioFocus使用情况的Listener，后续如果有别的程序要竞争AudioFocus，都是通过这个Listener的onAudioFocusChange()方法来通知这个AudioFocus的使用者的。
请求audio焦点属性
指示申请得到的AudioFocus不知道会持续多久，一般是长期占有；
指示要申请的AudioFocus是暂时性的，会很快用完释放的；
AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK不但说要申请的AudioFocus是暂时性的，还指示当前正在使用AudioFocus的可以继续播放，只是要“duck”一下（降低音量）。
AUDIOFOCUS_REQUEST_GRANTED：申请成功；
AUDIOFOCUS_REQUEST_FAILED：申请失败。
抢夺焦点
AUDIOFOCUS_GAIN：获得了Audio
Focus；
AUDIOFOCUS_LOSS：失去了Audio
Focus，并将会持续很长的时间。这里因为可能会停掉很长时间，所以不仅仅要停止Audio的播放，最好直接释放掉Media资源。而因为停止播放Audio的时间会很长，如果程序因为这个原因而失去AudioFocus，最好不要让它再次自动获得AudioFocus而继续播放，不然突然冒出来的声音会让用户感觉莫名其妙，感受很不好。这里直接放弃AudioFocus，当然也不用再侦听远程播放控制【如下面代码的处理】。要再次播放，除非用户再在界面上点击开始播放，才重新初始化Media，进行播放。
AUDIOFOCUS_LOSS_TRANSIENT：暂时失去Audio
Focus，并会很快再次获得。必须停止Audio的播放，但是因为可能会很快再次获得AudioFocus，这里可以不释放Media资源；
AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK：暂时失去AudioFocus，但是可以继续播放，不过要在降低音量。