I query data from SQLi to put in alarm manager after reboot phone like this
public class AlarmReset extends BroadcastReceiver {
SQLiteDatabase db;
DBHelper dbHelper;
Cursor cursor;
String type_number;
String op_name;
String sNotes;
@Override
public void onReceive(Context context, Intent intent) {
AlarmUtils au = new AlarmUtils();
if (intent.getAction().equals("android.intent.action.BOOT_COMPLETED")) {
// Set the alarm here.
db = dbHelper.getWritableDatabase();
String[] queryColumns = new String[]{DBHelper.COL_DATE,DBHelper.COL_RQCODE , DBHelper.COL_VEHICLE_TYPE, DBHelper.COL_OPTION_NAME};
cursor = db.query(DBHelper.TABLE_NAME, queryColumns, null,null,null,null,null);
while (cursor.moveToNext()) {
au.setAlarm(cursor.getString(0), Integer.parseInt(cursor.getString(1)), "Test !");
}
}
db.close();
}
}
After reboot I open app again it show error like this.
java.lang.RuntimeException: Unable to start receiver com.example.max.driver_app.AlarmReset: java.lang.NullPointerException
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2438)
at android.app.ActivityThread.access$1700(ActivityThread.java:143)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1285)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5059)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:818)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.max.driver_app.AlarmReset.onReceive(AlarmReset.java:40)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2431)
I think ploblem occor when query database but I recheck code I think the query has no problem. How to fix it ?
You need to initialise dbHelper before calling getWritableDatabase() or any other method on it.