Question

首先抱歉我的英语。所以我正在制作一个程序，在他/她需要时提醒用户进入他/她的药物。我的基本想法：

1 AlarmManager向我发送信号
2我用我的广播接收器捕捉到这个信号，
3，广播接收器启动我的服务和我的活动。

从10分钟到每分钟的服务倒计时将检查数据库中的其他参数并且活动将发出声音和振动。因为我会列出更多药物纽扣。并且因为服务和活动使用相同的游标，所以服务与之连接数据库。所以当我的Activity开始时，它需要从服务中获取光标（对于cursoradapter）。如果服务或活动改变了光标我需要刷新光标，所以我在服务中进行重新查询。

唯一的问题是虽然我的bindService给了我真实的结果，我的onServiceConnected 方法没有运行，所以我得到一个nullpointer异常，当我尝试调用公共服务方法（对于游标）从我的活动。我尝试在onStartCommand之后从服务启动我的Activity，但结果也是一个nullpointer。

实现任务的最佳方法是什么？我应该删除我的服务并从将执行服务工作的活动中创建另一个线程（AsyncTask）吗？

好的，我试图抓住重要部分。

package elte.thesis.broadcastreceivers;

import elte.thesis.alarmsmanager.AlarmActivity;
import elte.thesis.alarmsmanager.WakeLockManager;
import elte.thesis.database.Utility;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

/*
 * This BroadcastReceiver will receive the ALARM from the AlarmManager
 * and it will 
 * 1, start the Service and 
 * 2, show the AlarmActivity 
 */
public class DosageAlarmReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    Log.v("Szakbarbar",
            "AlarmManager send me the next " + "alarm time: " +    intent.getStringExtra("AlarmTime"));

    /*
     * It seems that the alarmmanager release the wakelock as soon as our
     * onReceive method return, so we need to make our own wakelock
     */
    WakeLockManager.acquireCpuWakeLock(context);

    /*
     * Start the service and give him the time what we got from alarm manager
     */
    Log.v("Szakbarbar", "Elinditjuk a servicunket");
    Intent serviceIntent = new Intent(Utility.ALARM_SERVICE);
    serviceIntent.putExtra("AlarmTime", intent.getStringExtra("AlarmTime"));
    context.startService(serviceIntent);

    /*
     * Start the AlarmActivity where the user can sign that he got in the
     * pills
     */
    Log.v("Szakbarbar", "Elinditjuk az activitinket");
    Intent alarmActivity = new Intent(context, AlarmActivity.class);
    alarmActivity.putExtra("AlarmTime", intent.getStringExtra("AlarmTime"));
    alarmActivity.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_NO_USER_ACTION);
    context.startActivity(alarmActivity);

}

 }

在我的AlarmActivity中

 AlarmService mService;
 ...
@Override
public void onStart() {
    super.onStart();

    Log.v("Szakbarbar", "Bind to the Service");
    Intent intent = new Intent(Utility.ALARM_SERVICE);
    boolean connection = bindService(intent, mConnection,      Context.BIND_AUTO_CREATE);
    Log.v("Szakbarbar", "Binded to the Service : " +      ((connection==true)?"kapcsolt":"nemkapcsolt"));
}

@Override
public void onResume() {
    super.onResume();

    Log.v("Szakbarbar", "Need the cursor from the Service");
    updateDosageAdapter();

    //Make one private register to now when the AlarmService made change on the cursor
    registerReceiver(mReceiver, new IntentFilter(Utility.ALARMS_CHANGED));

    if (!mute) {
        if (volume < 1)
            incAlarmVolume();
        mVibrator.vibrate(sVibratePattern, 0);
        player.start();
    }
}

/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName className, IBinder service) {
        // We've bound to LocalService, cast the IBinder and get LocalService instance
        Log.v("Szakbarbar", "mService itt még nulla");
        LocalBinder binder = (LocalBinder) service;
        mService = binder.getService();
        mBound = true;
        Log.v("Szakbarbar", "mService itt már nem nulla");          
    }

    @Override
    public void onServiceDisconnected(ComponentName arg0) {
        mBound = false;
    }
};
public void updateDosageAdapter() {
    Log.v("Szakbarbar", "1");
    alarmsCursor = mService.refreshCursor();
    Log.v("Szakbarbar", "2");       
    startManagingCursor(alarmsCursor);
    Log.v("Szakbarbar", "3");       
    if (alarmsAdapter == null) {
        Log.v("Szakbarbar", "4");           
        alarmsAdapter = new AlarmsAdapter(this, alarmsCursor);
        alarmsList = (ListView) findViewById(R.id.dosage_alarm_list);
        alarmsList.setAdapter(alarmsAdapter);
        alarmsList.setVerticalScrollBarEnabled(true);
        alarmsList.setScrollContainer(false);
        alarmsList.setOnCreateContextMenuListener(this);
    } else {
        Log.v("Where is nullpointerexception", "5");            
        alarmsAdapter.changeCursor(alarmsCursor);
    }
}

在我的服务中

 private final IBinder mBinder = new LocalBinder();
 ...
// Return this instance of AlarmService so clients can call public methods
public class LocalBinder extends Binder {
    AlarmService getService() {
        return AlarmService.this;
    }
}

@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}

//Refresh the cursor
public Cursor refreshCursor() {

    Log.v("Szakbarbar", "ResreshCrusor : " + alarmTime);

    alarmCursor = Utility.selectDosageAlarms(alarmTime);        
    return alarmCursor;
}

我的问题的简短描述 我想你还不知道我的问题是什么。我不擅长英语，对不起有问题。虽然我在onStart（）上调用了bindService（） AlarmActivity的方法，当我调用（也来自AlarmActivity）updateDosageAdapter（）时，使用我获得的服务中的refreshCursor（）方法一个空指针异常，因为onServiceConnected（）方法还没有运行，我的mService varieble应该保持我的服务的引用为空。

Answer 1

我设法找到了this post

中描述的解决方案

从broadcastreceiver开始活动和服务

1 个答案: