Android Println需要一条消息

我正在尝试以下应用程序，但当我运行它时，我得到一个异常“println需要一个消息”。有人能帮我吗。以下是课程

接收器类别

package com.sms;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract.PhoneLookup;
import android.telephony.SmsMessage;
import android.widget.Toast;

public class SMSReceiver extends BroadcastReceiver
{
     String name=null;
    private Context mContext;


    @Override
    public void onReceive(Context context, Intent intent)
    {   
        // TODO Auto-generated method stub

        int n;
        Bundle bundle = intent.getExtras();
        Object pdus[] = (Object[]) bundle.get("pdus");
        SmsMessage smsMessage[] = new SmsMessage[pdus.length];
        for (n = 0; n < pdus.length; n++)
        {
            smsMessage[n] = SmsMessage.createFromPdu((byte[]) pdus[n]);
        }
        // show first message
        String sms1 = smsMessage[0].getMessageBody();
        String from = smsMessage[0].getOriginatingAddress();
        //String name = getDisplayNameFromPhoneNo( from);
        Uri lookupUri = Uri.withAppendedPath(PhoneLookup.CONTENT_FILTER_URI, Uri.encode(from));
        Cursor c = context.getContentResolver().query(lookupUri, new String[]{PhoneLookup.DISPLAY_NAME}, null, null, null);
         while(c.moveToNext()){ 
                /* If we find a match we put it in a String.*/ 
               name = c.getString(c.getColumnIndexOrThrow(PhoneLookup.DISPLAY_NAME));  
                 }

        //Toast toast = Toast.makeText(context, "SMS Received from: " + from, Toast.LENGTH_LONG);
        //toast.show();

        System.out.println("!!!!"+name);
        //Toast.makeText(context, "name: " + name, Toast.LENGTH_LONG).show();
         Intent sIntent=new Intent(context,SMSTalk.class);
            sIntent.putExtra("stringdata",name);
            context.startService(sIntent);

        /*SMSTalk smsTalk = new SMSTalk();
        smsTalk.readName(name);*/
        //context.startService(new Intent(context,SMSTalk.class));
    }


}

清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.sms"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">

         <receiver android:name=".SMSReceiver" android:enabled="true">              
          <intent-filter>                   
           <action android:name="android.provider.Telephony.SMS_RECEIVED"/>               
           </intent-filter>         
            </receiver>
            <service android:name=".SMSTalk"


            ></service>

    </application>
    <uses-sdk android:minSdkVersion="5" />    
    <uses-permission android:name="android.permission.RECEIVE_SMS"></uses-permission>
    <uses-permission android:name="android.permission.READ_CONTACTS"></uses-permission>


</manifest> 

09-16 15:35:19.015: ERROR/AndroidRuntime(1148): FATAL EXCEPTION: main
09-16 15:35:19.015: ERROR/AndroidRuntime(1148): java.lang.NullPointerException: println needs a message
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.util.Log.println_native(Native Method)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.util.Log.i(Log.java:158)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.speech.tts.TextToSpeech.speak(TextToSpeech.java:720)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at com.sms.SMSTalk.onInit(SMSTalk.java:56)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.speech.tts.TextToSpeech$1.onServiceConnected(TextToSpeech.java:451)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1064)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1081)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.os.Handler.handleCallback(Handler.java:587)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.os.Looper.loop(Looper.java:123)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at android.app.ActivityThread.main(ActivityThread.java:3647)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at java.lang.reflect.Method.invokeNative(Native Method)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at java.lang.reflect.Method.invoke(Method.java:507)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
09-16 15:35:19.015: ERROR/AndroidRuntime(1148):     at dalvik.system.NativeStart.main(Native Method)

---

显然，当它执行以下行时，

msg

尚未初始化：

mTts.speak(msg,0, null);

所以把这个改成

public String msg=null;

为此：

public String msg="";

---

或者根据您想要做的事情，使用适当的内容初始化它。

我认为这行的

onInit（）方法中的
mTts.speak（msg，0，null）为空。请添加一个空检查。保留断点并尝试调试。+1。在
onStartCommand
中还有一个
msg
，一个作为类成员。删除onStartCommand中的
msg
声明。是的，谢谢varun..这就是问题所在。现在它已更正。Thanx all
public String msg="";