我创建了一个简单的语音识别服务:为此,我创建了android.speech.RecognitionService
的子类,并创建了一个活动来启动和停止该服务。
我的自定义语音识别服务简单地使用了默认的语音识别器,因为我的目标只是了解RecognitionService
和RecognitionService.Callback
类的工作原理。
public class SimpleVoiceService extends RecognitionService {
private SpeechRecognizer m_EngineSR;
@Override
public void onCreate() {
super.onCreate();
Log.i("SimpleVoiceService", "Service started");
}
@Override
public void onDestroy() {
super.onDestroy();
Log.i("SimpleVoiceService", "Service stopped");
}
@Override
protected void onCancel(Callback listener) {
m_EngineSR.cancel();
}
@Override
protected void onStartListening(Intent recognizerIntent, Callback listener) {
m_EngineSR.setRecognitionListener(new VoiceResultsListener(listener));
m_EngineSR.startListening(recognizerIntent);
}
@Override
protected void onStopListening(Callback listener) {
m_EngineSR.stopListening();
}
/**
*
*/
private class VoiceResultsListener implements RecognitionListener {
private Callback m_UserSpecifiedListener;
/**
*
* @param userSpecifiedListener
*/
public VoiceResultsListener(Callback userSpecifiedListener) {
m_UserSpecifiedListener = userSpecifiedListener;
}
@Override
public void onBeginningOfSpeech() {
try {
m_UserSpecifiedListener.beginningOfSpeech();
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onBufferReceived(byte[] buffer) {
try {
m_UserSpecifiedListener.bufferReceived(buffer);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onEndOfSpeech() {
try {
m_UserSpecifiedListener.endOfSpeech();
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onError(int error) {
try {
m_UserSpecifiedListener.error(error);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onEvent(int eventType, Bundle params) { ; }
@Override
public void onPartialResults(Bundle partialResults) {
try {
m_UserSpecifiedListener.partialResults(partialResults);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onReadyForSpeech(Bundle params) {
try {
m_UserSpecifiedListener.readyForSpeech(params);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onResults(Bundle results) {
try {
m_UserSpecifiedListener.results(results);
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onRmsChanged(float rmsdB) {
try {
m_UserSpecifiedListener.rmsChanged(rmsdB);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
}
我使用以下活动来启动和停止服务。
public class VoiceServiceStarterActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Button startButton = new Button(this);
startButton.setText("Start the service");
startButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) { startVoiceService(); }
});
Button stopButton = new Button(this);
stopButton.setText("Stop the service");
stopButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) { stopVoiceService(); }
});
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.addView(startButton);
layout.addView(stopButton);
setContentView(layout);
}
private void startVoiceService() {
startService(new Intent(this, SimpleVoiceService.class));
}
private void stopVoiceService() {
stopService(new Intent(this, SimpleVoiceService.class));
}
}
最后我在AndroidManifest.xml
中声明了我的服务(请参见Android SDK文件夹中的VoiceRecognition示例)。
<service android:name="SimpleVoiceService"
android:label="@string/service_name" >
<intent-filter>
<action android:name="android.speech.RecognitionService" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</service>
然后我在安卓设备上安装了这个应用程序并启动它: - 当我启动服务时,它会正常启动; - 当我停止它时,它会正常停止。
但是,如果我在另一个活动中启动以下代码,则activities
List
仅包含一个元素,即默认的语音识别器。
PackageManager pm = getPackageManager();
List<ResolveInfo> activities = pm.queryIntentActivities(
new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
为什么我的语音识别器没有出现在系统中?