基于javascript的Firebase查询

我正在创建一个测验应用程序，我想按级别和类别过滤我的数据库问题，但我不知道怎么做。我已经实现了levelRef来获取级别并在屏幕上显示它。 我还想获取类别并过滤问题（例如：如果用户点击sport，我将只显示sport问题）

这是我的密码 `私有void updateQuestion（）{ 倒计时。取消（）

    mQuestionRef = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/question");
    mQuestionRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String question = dataSnapshot.getValue(String.class);
            mQuestion.setText(question);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mChoice1Ref = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/choice1");
    mChoice1Ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String choice = dataSnapshot.getValue(String.class);
            mButtonChoice1.setText(choice);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mChoice2Ref = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/choice2");
    mChoice2Ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String choice = dataSnapshot.getValue(String.class);
            mButtonChoice2.setText(choice);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mChoice3Ref = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/choice3");
    mChoice3Ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String choice = dataSnapshot.getValue(String.class);
            mButtonChoice3.setText(choice);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mChoice4Ref = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/choice4");
    mChoice4Ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String choice = dataSnapshot.getValue(String.class);
            mButtonChoice4.setText(choice);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mAnswerRef = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/answer");
    mAnswerRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            mAnswer = dataSnapshot.getValue(String.class);
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

    mLevelRef = new Firebase("https://quizer-f3732.firebaseio.com/Questions/" + mQuestionNumber + "/level");
    mLevelRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            level = dataSnapshot.getValue(String.class);
            mLevel.setText("Livello " + level);

        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });


    mProgressQuestion.incrementProgressBy(PROGRESS_INCREMENT);
    mQuestionNumber++;
    timeLeftInMillis = COUNTDOWN_IN_MILLIS;
    startCountDown();



}`