本文介绍了Android的语音识别服务空指针异常的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想创建一个Android的语音服务认可下这里的例子：
Android语音识别连续服务
和下面是我的code：
公共类MainActivity延伸活动{ 私人诠释mBindFlag;
信使mServiceMessenger;
@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
super.onCreate（savedInstanceState）;
上下文activityContext = getApplicationContext（）;
意向书的服务=新意图（activityContext，VoiceCommandService.class）;
activityContext.startService（服务）;
mBindFlag = Build.VERSION.SDK_INT＆LT; Build.VERSION_ codeS.ICE_CREAM_SANDWICH？ 0：Context.BIND_ABOVE_CLIENT;
} 私人最终ServiceConnection mServiceConnection =新ServiceConnection（）
{
@覆盖
公共无效onServiceConnected（组件名名称，服务的IBinder）
{
//如果（调试）{Log.d（TAGonServiceConnected）;} // $ NON-NLS-1 $ mServiceMessenger =新使者（服务）;
消息味精=新的Message（）;
msg.what = VoiceCommandService.MSG_RECOGNIZER_START_LISTENING;
VoiceCommandService voiceCommandService =新VoiceCommandService（）;
尝试
{
voiceCommandService.mServerMessenger.send（MSG）;
}
赶上（RemoteException的E）
{
e.printStackTrace（）;
}
} @覆盖
公共无效onServiceDisconnected（组件名名）
{
//如果（调试）{Log.d（TAGonServiceDisconnected）;} // $ NON-NLS-1 $
mServiceMessenger = NULL;
} };
@覆盖
保护无效调用onStart（）
{
super.onStart（）; bindService（新意图（这一点，VoiceCommandService.class），mServiceConnection，mBindFlag）;
} 公共类VoiceCommandService延伸服务
{
保护AudioManager mAudioManager;
保护SpeechRecognizer mSpeechRecognizer;
保护意图mSpeechRecognizerIntent;
保护最终信使mServerMessenger =新信使（新IncomingHandler（本））; 保护布尔mIsListening;
保护挥发性布尔mIsCountDownOn; 静态最终诠释MSG_RECOGNIZER_START_LISTENING = 1;
静态最终诠释MSG_RECOGNIZER_CANCEL = 2;
@覆盖
公共无效的onCreate（）
{
super.onCreate（）;
mAudioManager =（AudioManager）getSystemService（Context.AUDIO_SERVICE）;
mSpeechRecognizer = SpeechRecognizer.createSpeechRecognizer（本）;
mSpeechRecognizer.setRecognitionListener（新SpeechRecognitionListener（））;
mSpeechRecognizerIntent =新意图（RecognizerIntent.ACTION_RECOGNIZE_SPEECH）;
mSpeechRecognizerIntent.putExtra（RecognizerIntent.EXTRA_LANGUAGE_MODEL，
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM）;
mSpeechRecognizerIntent.putExtra（RecognizerIntent.EXTRA_CALLING_PACKAGE，
this.getPackageName（））;
} 保护类IncomingHandler扩展了Handler
{
私人的WeakReference＆LT; VoiceCommandService＆GT; mtarget; IncomingHandler（VoiceCommandService目标）
{
mtarget =新的WeakReference＆LT; VoiceCommandService＆GT;（目标）;
}
@覆盖
公共无效的handleMessage（消息MSG）
{
最终VoiceCommandService目标= mtarget.get（）; 开关（msg.what）
{
案例MSG_RECOGNIZER_START_LISTENING： 如果（Build.VERSION.SDK_INT＆GT; = Build.VERSION_ codeS.JELLY_BEAN）
{
//关闭蜂鸣声
target.mAudioManager.setStreamMute（AudioManager.STREAM_SYSTEM，FALSE）;
}
如果（！target.mIsListening）
{
target.mSpeechRecognizer.startListening（target.mSpeechRecognizerIntent）;
target.mIsListening = TRUE;
//Log.d(TAG，消息开始听）; // $ NON-NLS-1 $
}
打破; 案例MSG_RECOGNIZER_CANCEL：
target.mSpeechRecognizer.cancel（）;
target.mIsListening = FALSE;
//Log.d(TAG，消息取消识别）; // $ NON-NLS-1 $
打破;
}
}
} //倒计时定时器果冻豆解决
保护CountDownTimer mNoSpeechCountDown =新CountDownTimer（5000，5000）
{ @覆盖
公共无效onTick（长millisUntilFinished）
{
// TODO自动生成方法存根 } @覆盖
公共无效onFinish（）
{
mIsCountDownOn = FALSE;
消息消息= Message.obtain（NULL，MSG_RECOGNIZER_CANCEL）;
尝试
{
mServerMessenger.send（消息）;
消息= Message.obtain（NULL，MSG_RECOGNIZER_START_LISTENING）;
mServerMessenger.send（消息）;
}
赶上（RemoteException的E）
{ }
}
}; @覆盖
公共无效的onDestroy（）
{
super.onDestroy（）; 如果（mIsCountDownOn）
{
mNoSpeechCountDown.cancel（）;
}
如果（mSpeechRecognizer！= NULL）
{
mSpeechRecognizer.destroy（）;
}
} 保护类SpeechRecognitionListener实现RecognitionListener
{ 私有静态最后弦乐TAG =SpeechRecognitionListener; @覆盖
公共无效onBeginningOfSpeech（）
{
//语音输入将被处理，所以没有必要为向下计数了
如果（mIsCountDownOn）
{
mIsCountDownOn = FALSE;
mNoSpeechCountDown.cancel（）;
}
//Log.d(TAGonBeginingOfSpeech）; // $ NON-NLS-1 $
} @覆盖
公共无效onBufferReceived（字节[]缓冲区）
{ } @覆盖
公共无效onEndOfSpeech（）
{
//Log.d(TAGonEndOfSpeech）; // $ NON-NLS-1 $
} @覆盖
公共无效onerror的（INT错误）
{
如果（mIsCountDownOn）
{
mIsCountDownOn = FALSE;
mNoSpeechCountDown.cancel（）;
}
mIsListening = FALSE;
消息消息= Message.obtain（NULL，MSG_RECOGNIZER_START_LISTENING）;
尝试
{
mServerMessenger.send（消息）;
}
赶上（RemoteException的E）
{ }
//Log.d(TAG，错误=+误差）; // $ NON-NLS-1 $
} @覆盖
公共无效的onEvent（INT EVENTTYPE，捆绑PARAMS）
{ } @覆盖
公共无效onPartialResults（捆绑partialResults）
{ } @覆盖
公共无效onReadyForSpeech（捆绑PARAMS）
{
如果（Build.VERSION.SDK_INT＆GT; = Build.VERSION_ codeS.JELLY_BEAN）
{
mIsCountDownOn =真;
mNoSpeechCountDown.start（）;
mAudioManager.setStreamMute（AudioManager.STREAM_SYSTEM，FALSE）;
}
//Log.d(TAGonReadyForSpeech）; // $ NON-NLS-1 $
} @覆盖
公共无效onResults（捆绑结果）
{
//Log.d(TAGonResults）; // $ NON-NLS-1 $
Toast.makeText（getApplicationContext（），这是我的吐司消息！=），
Toast.LENGTH_LONG）.show（）;
} @覆盖
公共无效onRmsChanged（浮动rmsdB）
{ } } @覆盖
公众的IBinder onBind（意向为arg0）{
// TODO自动生成方法存根
返回mServerMessenger.getBinder（）;
}
}
}
有人可以帮我找出为什么我遇到了空指针异常与 mTarget.AudioManager 和 mTarget.SpeechRecognitionIntent ？我也看到我的服务onCreate方法是不是击中。能否请你告诉我正确的方法呢？
更新 - 在尝试调用服务的BindService方法，但没有被调用我的服务onCreate方法。可否请您指出我是什么不见了？
解决方案
VoiceCommandService voiceCommandService =新VoiceCommandService（）
不要实例化服务新 - 生命周期的方法，如的onCreate（）不会被调用。
使用的意图。
i am trying to create an android speech recognitions service following the example here:
Android Speech Recognition Continuous Service
and below is my code:
public class MainActivity extends Activity {
private int mBindFlag;
Messenger mServiceMessenger;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Context activityContext = getApplicationContext();
Intent service = new Intent(activityContext, VoiceCommandService.class);
activityContext.startService(service);
mBindFlag = Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH ? 0 : Context.BIND_ABOVE_CLIENT;
}
private final ServiceConnection mServiceConnection = new ServiceConnection()
{
@Override
public void onServiceConnected(ComponentName name, IBinder service)
{
//if (DEBUG) {Log.d(TAG, "onServiceConnected");} //$NON-NLS-1$
mServiceMessenger = new Messenger(service);
Message msg = new Message();
msg.what = VoiceCommandService.MSG_RECOGNIZER_START_LISTENING;
VoiceCommandService voiceCommandService = new VoiceCommandService();
try
{
voiceCommandService.mServerMessenger.send(msg);
}
catch (RemoteException e)
{
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName name)
{
//if (DEBUG) {Log.d(TAG, "onServiceDisconnected");} //$NON-NLS-1$
mServiceMessenger = null;
}
};
@Override
protected void onStart()
{
super.onStart();
bindService(new Intent(this, VoiceCommandService.class), mServiceConnection, mBindFlag);
}
public class VoiceCommandService extends Service
{
protected AudioManager mAudioManager;
protected SpeechRecognizer mSpeechRecognizer;
protected Intent mSpeechRecognizerIntent;
protected final Messenger mServerMessenger = new Messenger(new IncomingHandler(this));
protected boolean mIsListening;
protected volatile boolean mIsCountDownOn;
static final int MSG_RECOGNIZER_START_LISTENING = 1;
static final int MSG_RECOGNIZER_CANCEL = 2;
@Override
public void onCreate()
{
super.onCreate();
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
mSpeechRecognizer = SpeechRecognizer.createSpeechRecognizer(this);
mSpeechRecognizer.setRecognitionListener(new SpeechRecognitionListener());
mSpeechRecognizerIntent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
mSpeechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
mSpeechRecognizerIntent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE,
this.getPackageName());
}
protected class IncomingHandler extends Handler
{
private WeakReference<VoiceCommandService> mtarget;
IncomingHandler(VoiceCommandService target)
{
mtarget = new WeakReference<VoiceCommandService>(target);
}
@Override
public void handleMessage(Message msg)
{
final VoiceCommandService target = mtarget.get();
switch (msg.what)
{
case MSG_RECOGNIZER_START_LISTENING:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
{
// turn off beep sound
target.mAudioManager.setStreamMute(AudioManager.STREAM_SYSTEM, false);
}
if (!target.mIsListening)
{
target.mSpeechRecognizer.startListening(target.mSpeechRecognizerIntent);
target.mIsListening = true;
//Log.d(TAG, "message start listening"); //$NON-NLS-1$
}
break;
case MSG_RECOGNIZER_CANCEL:
target.mSpeechRecognizer.cancel();
target.mIsListening = false;
//Log.d(TAG, "message canceled recognizer"); //$NON-NLS-1$
break;
}
}
}
// Count down timer for Jelly Bean work around
protected CountDownTimer mNoSpeechCountDown = new CountDownTimer(5000, 5000)
{
@Override
public void onTick(long millisUntilFinished)
{
// TODO Auto-generated method stub
}
@Override
public void onFinish()
{
mIsCountDownOn = false;
Message message = Message.obtain(null, MSG_RECOGNIZER_CANCEL);
try
{
mServerMessenger.send(message);
message = Message.obtain(null, MSG_RECOGNIZER_START_LISTENING);
mServerMessenger.send(message);
}
catch (RemoteException e)
{
}
}
};
@Override
public void onDestroy()
{
super.onDestroy();
if (mIsCountDownOn)
{
mNoSpeechCountDown.cancel();
}
if (mSpeechRecognizer != null)
{
mSpeechRecognizer.destroy();
}
}
protected class SpeechRecognitionListener implements RecognitionListener
{
private static final String TAG = "SpeechRecognitionListener";
@Override
public void onBeginningOfSpeech()
{
// speech input will be processed, so there is no need for count down anymore
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mNoSpeechCountDown.cancel();
}
//Log.d(TAG, "onBeginingOfSpeech"); //$NON-NLS-1$
}
@Override
public void onBufferReceived(byte[] buffer)
{
}
@Override
public void onEndOfSpeech()
{
//Log.d(TAG, "onEndOfSpeech"); //$NON-NLS-1$
}
@Override
public void onError(int error)
{
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mNoSpeechCountDown.cancel();
}
mIsListening = false;
Message message = Message.obtain(null, MSG_RECOGNIZER_START_LISTENING);
try
{
mServerMessenger.send(message);
}
catch (RemoteException e)
{
}
//Log.d(TAG, "error = " + error); //$NON-NLS-1$
}
@Override
public void onEvent(int eventType, Bundle params)
{
}
@Override
public void onPartialResults(Bundle partialResults)
{
}
@Override
public void onReadyForSpeech(Bundle params)
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
{
mIsCountDownOn = true;
mNoSpeechCountDown.start();
mAudioManager.setStreamMute(AudioManager.STREAM_SYSTEM, false);
}
//Log.d(TAG, "onReadyForSpeech"); //$NON-NLS-1$
}
@Override
public void onResults(Bundle results)
{
//Log.d(TAG, "onResults"); //$NON-NLS-1$
Toast.makeText(getApplicationContext(), "this is my Toast message!!! =)",
Toast.LENGTH_LONG).show();
}
@Override
public void onRmsChanged(float rmsdB)
{
}
}
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return mServerMessenger.getBinder();
}
}
}
Can someone please help me find out why am running into nullpointer exception with mTarget.AudioManager and mTarget.SpeechRecognitionIntent? i also see that my service OnCreate method is not getting hit. Can please tell me the right approach?
update - am trying to invoke the service in the BindService method, yet my Oncreate method in the service is not being invoked. Can please point out what am missing?
解决方案
VoiceCommandService voiceCommandService = new VoiceCommandService()
Don't instantiate services with new - lifecycle methods such as onCreate() won't get invoked.
Use an Intent.
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