java.lang.RuntimeException：無法實例化服務：java.lang.NullPointerException

-2

我是一個完整的newcome android和java和我正在寫android應用程序與android工作室，應顯示在地圖上的每個5秒點（這只是一個測試）。當我運行模擬器上的應用程序，我得到這個在logcat的：java.lang.RuntimeException：無法實例化服務：java.lang.NullPointerException

03-13 13:22:28.373 2964-2964/com.example.francesca.geoapp  

E/AndroidRuntime﹕ FATAL EXCEPTION: main 
Process: com.example.francesca.geoapp, PID: 2964 
java.lang.RuntimeException: Unable to instantiate service com.example.francesca.geoapp.DataService: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference 
     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2716) 
     at android.app.ActivityThread.access$1800(ActivityThread.java:144) 
     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1361) 
     at android.os.Handler.dispatchMessage(Handler.java:102) 
     at android.os.Looper.loop(Looper.java:135) 
     at android.app.ActivityThread.main(ActivityThread.java:5221) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at java.lang.reflect.Method.invoke(Method.java:372) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference 
     at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:105) 
     at android.support.v4.content.LocalBroadcastManager.getInstance(LocalBroadcastManag er.java:102) at com.example.francesca.geoapp.DataService.<init> (DataService.java:56) 
     at java.lang.reflect.Constructor.newInstance(Native Method) 
     at java.lang.Class.newInstance(Class.java:1572) 
     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2713) 
            at android.app.ActivityThread.access$1800(ActivityThread.java:144) 
            at  android.app.ActivityThread$H.handleMessage(ActivityThread.java:1361) 
            at android.os.Handler.dispatchMessage(Handler.java:102) 
            at android.os.Looper.loop(Looper.java:135) 
            at android.app.ActivityThread.main(ActivityThread.java:5221) 
            at java.lang.reflect.Method.invoke(Native Method) 
            at java.lang.reflect.Method.invoke(Method.java:372) 
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

的intentService DataService的代碼是

public class DataService extends IntentService { 

private LocalBroadcastManager BroadcastNotifier ; 
private Timer timer = new Timer(); 
private List dataList = new ArrayList<testData>(); 
int i = 0; 

//constructor 
public DataService() { 
    super("DataService"); 

    dataList.add(new testData(new LatLng(52.519804, 13.404988), new LatLng(52.519125, 13.406061), 50, 30)); 
    dataList.add(new testData(new LatLng(52.520692, 13.403722), new LatLng(52.519804, 13.404988), 60, 40)); 
    dataList.add(new testData(new LatLng(52.522023, 13.404730), new LatLng(52.520692, 13.403722), 50, 30)); 
    dataList.add(new testData(new LatLng(52.523388, 13.407143), new LatLng(52.522023, 13.404730), 40, 20)); 
    dataList.add(new testData(new LatLng(52.522911, 13.408807), new LatLng(52.523388, 13.407143), 80, 30)); 
    dataList.add(new testData(new LatLng(52.523982, 13.409623), new LatLng(52.522911, 13.408807), 50, 40)); 
    dataList.add(new testData(new LatLng(52.524713, 13.407434), new LatLng(52.523982, 13.409623), 30, 50)); 

    BroadcastNotifier = LocalBroadcastManager.getInstance(this); 
    timer.scheduleAtFixedRate(task, 0, 5000); 
} 

protected void onHandleIntent(Intent i) { 

} 

//timerTask to send request to the webservice 
TimerTask task = new TimerTask() { 
    @Override 
    public void run() { 
     if(i <7) { 
      testData test = (testData) dataList.get(i); 
      data.setCurrentPosition(test.currentPosition); 
      data.setLatestPosition(test.latestPosition); 
      data.setSpeed(test.speed); 
      data.setMediumSpeed(test.mediumSpeed); 
      i++; 
     } 
    } 
}; 


//method to tell subscribers that a newData has arrived 
private void OnNewDataSeen() { 
    Intent localIntent = new Intent(); 
    localIntent.setAction("com.example.android.threadsample.BROADCAST"); 

    localIntent.addCategory(Intent.CATEGORY_DEFAULT); 

    // Broadcasts the Intent 
    BroadcastNotifier.sendBroadcast(localIntent); 
}

}

，並應啓動intentService的MenuActivity被

}

我做錯了什麼？

來源

2015-03-13 francesca cipollini

問了很多次，你正試圖在上下文創建之前使用上下文（在構造函數中） – Selvin 2015-03-13 14:26:28

你不能有這個

BroadcastNotifier = LocalBroadcastManager.getInstance(this);

在你的構造函數

。把它放入onHandleIntent()

this沒有完全在你的構造函數初始化和Context無法獲得，它爲什麼它是null，你會得到NPE。

來源

2015-03-13 14:26:51

throat you so much！它正在運行:) – 2015-03-13 15:23:42

不需要包含只是一個謝謝你的評論，stackoverflow的方式是「接受」和/或「upvote」最能幫助你的答案。 – 2015-03-13 15:28:06

您應該僅給super打電話並使用onCreate生命週期回調方法。

來源

2016-12-13 23:00:12 Mohsenme

java.lang.RuntimeException：無法實例化服務：java.lang.NullPointerException

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