将推送消息从GCM存储到数据库中

Question

我需要从GCM获取消息，然后将它们存储在数据库中。实际上，重点是获取消息然后更改片段中的Recycler视图。因此，当这些通知即将发布时，它们会出现在片段中（所以服务在后台运行并保存消息）。我设置了一个gcmlistener服务，它具有onMessageReceived方法和数据库帮助程序类。但是这个数据库帮助器需要一个上下文，那么如何从GCMlistenerService传递一个上下文呢？

public class MyGcmListenerService extends GcmListenerService {

    private static final String TAG = "MyGcmListenerService";
    mySQLAdapter adapter = new mySQLAdapter(/*What to put here*/);


    @Override
    public void onMessageReceived(String from, Bundle data) {
        String message = data.getString("price");

        Log.d(TAG, "From: " + from);
        Log.d(TAG, "Message: " + message);

        if (from.startsWith("/topics/")) {
            // message received from some topic.
        } else {
            // normal downstream message.
        }      
        sendNotification(message);
        String time = DateFormat.getTimeInstance().toString();
        long id =  adapter.insertData("Information",message,time);
        if (id<0)
        Log.d("GCM","Unsuccess");
        else
        Log.d("GCM","Success");

        Intent intent = new Intent("token");
        intent.putExtra("message",message);
        intent.putExtra("typeOf","Info");
        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);

    }

public class mySQLAdapter {
    mySQLHelper helper;

    public mySQLAdapter(Context context) {
        helper = mySQLHelper.getmInstance(context);
    }

    public long insertData(String type, String description, String time) {
        SQLiteDatabase db = helper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(helper.TYPE, type);
        contentValues.put(helper.DESCRIPTION, description);
        contentValues.put(helper.TIME, time);
        long id = db.insert(mySQLHelper.TABLE_NAME, null, contentValues);
        return id;
    }

    public List<Notification> getData() {
        List<Notification> notifications = new ArrayList<>();
        SQLiteDatabase db = helper.getWritableDatabase();
        String[] columns = {mySQLHelper.UID, mySQLHelper.TYPE, mySQLHelper.DESCRIPTION, mySQLHelper.TIME};
        Cursor cursor = db.query(mySQLHelper.TABLE_NAME, columns, null, null, null, null, null);
        StringBuffer buffer = new StringBuffer();
        while (cursor.moveToNext()) {
            String type = cursor.getString(cursor.getColumnIndex(mySQLHelper.TYPE));
            String desc = cursor.getString(cursor.getColumnIndex(mySQLHelper.DESCRIPTION));
            String time = cursor.getString(cursor.getColumnIndex(mySQLHelper.TIME));
            Notification notification = new Notification(type, desc, time, 0);
            notifications.add(notification);
        }
        return notifications;
    }

    public static class mySQLHelper extends SQLiteOpenHelper {
        private static mySQLHelper mInstance = null;
        private static final String DATABASE_NAME = "notificationsDB";
        private static final String TABLE_NAME = "notifications";
        private static final String UID = "_id";
        private static final int VERSION = 0;
        private static final String TYPE = "Type";
        private static final String DESCRIPTION = "Description";
        private static final String TIME = "Time";
        private static final String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME
                + " (" + UID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + TYPE + " VARCHAR(255), " + DESCRIPTION + " VARCHAR(255), "
                + TIME + " VARCHAR(255));";
        private static final String DROP_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME;
        Context context;

        public static mySQLHelper getmInstance(Context context) {
            if (mInstance == null)
                mInstance = new mySQLHelper(context.getApplicationContext());
            return mInstance;
        }

        public mySQLHelper(Context context) {
            super(context, DATABASE_NAME, null, VERSION);
            this.context = context;
            Log.d("SQL", "constructor Called!");
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            try {
                Log.d("SQL", "Helper onCreate called");
                db.execSQL(CREATE_TABLE);
            } catch (SQLException e) {
                Log.d("SQL", "" + e);
                Log.d("SQL", "" + e);
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            try {
                Log.d("SQL", "Helper onUpgrade called");
                db.execSQL(DROP_TABLE);
                onCreate(db);
            } catch (SQLException e) {
                Log.d("SQL", "" + e);
                Log.d("SQL", "" + e);
            }

        }
    }
}