简体   繁体   中英

'java.lang.String android.content.Context.getPackageName()' on a null object reference error

I have a Database full of alarms, the service to create the alarms starts on boot, however crashes once in the loop to create them. the error is:

"java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference"

EDIT:

Code:

public class NotificationServiceStartOnBoot extends Service {

    UserDbHelper userDbHelper;
    SQLiteDatabase sqLiteDatabase;
    Context context;
    Cursor cursor;
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.e("SERVICE", "STARTED...");
        userDbHelper = new UserDbHelper(getApplicationContext());
        sqLiteDatabase = userDbHelper.getReadableDatabase();
        cursor = userDbHelper.getNotifications(sqLiteDatabase);
        Log.e("SERVICE", "About to begin loop...");
        if(cursor.moveToFirst())
        {
            Log.e("SERVICE", "if statement accepted...");
            do
            {
                Log.e("SERVICE", "notification loop begun...");
                String date,UID;

                date = cursor.getString(0);
                UID = cursor.getString(1);
               // Long notificationDate = Long.valueOf(date);
                Long notificationUID = Long.valueOf(UID);


                long milliSeconds= Long.parseLong(date);
                //System.out.println(milliSeconds);

                Calendar calendar = Calendar.getInstance();
                calendar.setTimeInMillis(milliSeconds);


                final int _id = (int) System.currentTimeMillis();
                Intent alarmIntent = new Intent(context, AlarmReceiver.class);
                alarmIntent.putExtra("nID", notificationUID);
                 //make sure the intent have id's
                PendingIntent pendingIntent = PendingIntent.getBroadcast(context, _id,  alarmIntent , 0);

                AlarmManager alarmManager = (AlarmManager)context.getSystemService(ALARM_SERVICE);
                alarmManager.set(AlarmManager.RTC, calendar.getTimeInMillis(), pendingIntent);

            }while (cursor.moveToNext());
        }
        Log.e("SERVICE", "outside if statement...");

        //NotificationGenerator.generateNotification(context, null, null, null, null);
    }

}

Your context is null. Context context; where did you set your context ? Set your context before use it.

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM