我试图开发一个应用程序，通过语音通知用户任何传入的消息，我有三个类，TextSpeaker，Receiver和SpeakerService。当我启动应用程序并单击“开始”按钮时，我收到运行时错误：
06-21 13:54:36.088: ERROR/AndroidRuntime(528): Uncaught handler: thread main exiting due to uncaught exception
06-21 13:54:36.119: ERROR/AndroidRuntime(528): java.lang.RuntimeException: Unable to start service com.example.TextSpeaker.SpeakerService@43bb2ff8 with Intent { cmp=com.example.TextSpeaker/.SpeakerService }: java.lang.NullPointerException
06-21 13:54:36.119: ERROR/AndroidRuntime(528): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2882)
....
06-21 13:54:36.119: ERROR/AndroidRuntime(528): Caused by: java.lang.NullPointerException
06-21 13:54:36.119: ERROR/AndroidRuntime(528): at com.example.TextSpeaker.SpeakerService.onStart(SpeakerService.java:33)
06-21 13:54:36.119: ERROR/AndroidRuntime(528): at android.app.Service.onStartCommand(Service.java:306)
06-21 13:54:36.119: ERROR/AndroidRuntime(528): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2873)
06-21 13:54:36.119: ERROR/AndroidRuntime(528): ... 10 more
以下是我的3个课程： TEXTSPEAKER CLASS：
package com.example.TextSpeaker;
import java.util.Locale;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
// the following programme converts the text to speech
public class TextSpeaker extends Activity implements OnInitListener {
/** Called when the activity is first created. */
int MY_DATA_CHECK_CODE = 0;
public TextToSpeech mtts;
public Button button,stop_button;
//public EditText edittext;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button = (Button)findViewById(R.id.button);
stop_button=(Button)findViewById(R.id.stop_button);
Intent myintent = new Intent();
myintent.setAction(TextToSpeech.Engine.ACTION_CHECK_TTS_DATA);
startActivityForResult(myintent, MY_DATA_CHECK_CODE);
//edit text=(EditText)findViewById(R.id.edittext);
}
public void buttonClickListener(View src){
switch(src.getId())
{
case(R.id.button):
Toast.makeText(getApplicationContext(), "The service has been started\n Every new message will now be read out", Toast.LENGTH_LONG).show();
startService(new Intent(this,SpeakerService.class));
break;
case(R.id.stop_button):
Toast.makeText(getApplicationContext(), "The service has been stopped\n ", Toast.LENGTH_LONG).show();
stopService(new Intent(this,SpeakerService.class));
break;
}
}
protected void onActivityResult(int requestcode,int resultcode,Intent data)
{
if(requestcode == MY_DATA_CHECK_CODE)
{
if(resultcode==TextToSpeech.Engine.CHECK_VOICE_DATA_PASS)
{
// success so create the TTS engine
mtts = new TextToSpeech(this,this);
mtts.setLanguage(Locale.ENGLISH);
}
else
{
//install the Engine
Intent install = new Intent();
install.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(install);
}
}
}
public void onDestroy(Bundle savedInstanceStatBundle)
{
mtts.shutdown();
}
//public void onPause()
//{
// super.onPause();
// // if our app has no focus
// if(mtts!=null)
// mtts.stop();
// }
@Override
public void onInit(int status) {
if(status==TextToSpeech.SUCCESS)
button.setEnabled(true);
}
}
RECEIVER CLASS：
package com.example.TextSpeaker;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage; // supports both gsm and cdma
import android.util.Log;
import android.widget.Toast;
public class Receiver extends BroadcastReceiver{
//TextSpeaker tsp=new TextSpeaker();
public String str="";
@Override
public void onReceive(Context context, Intent intent) {
Bundle bundle = intent.getExtras();
Log.d("Receiver","Message received successfully");
SmsMessage[] msgs = null;
if(bundle!=null)
{
// retrive the sms received
Object[] pdus = (Object[])bundle.get("pdus");
msgs = new SmsMessage[pdus.length];
for(int i=0;i<msgs.length;i++)
{
msgs[i]=SmsMessage.createFromPdu((byte[]) pdus[i]);
str+="Message From "+msgs[i].getOriginatingAddress()+".";
str+="The message is "+msgs[i].getMessageBody().toString();
}
Toast.makeText(context,str,Toast.LENGTH_SHORT).show();
}
}
}
SERVICESPERAKER CLASS：
package com.example.TextSpeaker;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.speech.tts.TextToSpeech;
import android.util.Log;
import android.widget.Toast;
public class SpeakerService extends Service {
Receiver rv = new Receiver();
TextSpeaker tspker = new TextSpeaker();
//public TextToSpeech mtts;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate(){
//mtts =new TextToSpeech(getBaseContext(), null);
Log.d("SpeakerService","Service created successfully!");
//mtts.speak(rv.str, TextToSpeech.QUEUE_FLUSH,null);
}
@Override
public void onStart(Intent intent,int startid)
{
Log.d("SpeakerService","Service started successfully!");
tspker.mtts.speak(rv.str, TextToSpeech.QUEUE_FLUSH,null);
}
@Override
public void onDestroy(){
if(tspker.mtts!=null)
{
tspker.mtts.stop();
Toast.makeText(getApplicationContext(),"The service has been destroyed!", Toast.LENGTH_SHORT).show();
}
}
}
答案 0 :(得分：1)
看起来像tspker.mtts是NULL。
在SpeakerService.onStart中添加一些日志记录，以检查或其他NULL情况：
public void onStart(Intent intent,int startid)
{
Log.d("SpeakerService","Service started successfully!");
Log.d("SpeakerService","rv = " + rv.toString());
Log.d("SpeakerService","tspker = " + tspker.toString());
Log.d("SpeakerService","tspker.mtts = " + tspker.mtts.toString());
tspker.mtts.speak(rv.str, TextToSpeech.QUEUE_FLUSH,null);
}