how to get random quiz question from firebase and add listener on end of questions in quiz

[Tanveer121]

I am a teacher and creating a quiz for my students rest is complete I have 500 questions on my firebase real-time database all I want to do is randomize questions each time 50 questions and set a listener after 50 questions

Here my quiz activity

public class grandtest extends AppCompatActivity {

TextView mQuestionTextView;
ProgressBar mProgressBar;
Button bchoice1,bchoice2,bchoice3,bchoice4;
Random Rand;
String mAnswer;
Timer mTimer;
TextView mScoreTextView;
public static int mScore;
int mQuestionNo = 0;

private Firebase mQuestionRef;
private Firebase mChoice1Ref;
private Firebase mChoice2Ref;
private Firebase mChoice3Ref;
private Firebase mChoice4Ref;
private Firebase mAnswerRef;

[USER=1021285]@override[/USER]
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_grandtest);

   mQuestionTextView = findViewById(R.id.mquestiontextview);
   mProgressBar = findViewById(R.id.progressBar);
   bchoice1 = findViewById(R.id.choice1);
   bchoice2 = findViewById(R.id.choice2);
   bchoice3 = findViewById(R.id.choice3);
   bchoice4 = findViewById(R.id.choice4);
   mScoreTextView = findViewById(R.id.mScore);
}


public void updateQuestion (){

   mQuestionRef = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo +"/question");
   mQuestionRef.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
       String question = dataSnapshot.getValue(String.class);
       mQuestionTextView.setText(question);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {
           Toast.makeText(grandtest.this,"Please enable data",Toast.LENGTH_SHORT).show();
       }
   });
   mChoice1Ref = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo+"/choice1");
   mChoice1Ref.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
           String choice1 = dataSnapshot.getValue(String.class);
           bchoice1.setText(choice1);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {

       }
   });
   mChoice2Ref = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo+"/choice2");
   mChoice2Ref.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
           String choice2 = dataSnapshot.getValue(String.class);
           bchoice2.setText(choice2);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {

       }
   });
   mChoice3Ref = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo+"/choice3");
   mChoice3Ref.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
           String choice3 = dataSnapshot.getValue(String.class);
           bchoice3.setText(choice3);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {

       }
   });
   mChoice4Ref = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo+"/choice4");
   mChoice4Ref.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
           String choice4 = dataSnapshot.getValue(String.class);
           bchoice4.setText(choice4);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {

       }
   });
   mAnswerRef = new Firebase("https://class9notes-2808b.firebaseio.com/"+mQuestionNo+"/answer");
   mAnswerRef.addValueEventListener(new ValueEventListener() {
       [USER=1021285]@override[/USER]
       public void onDataChange(DataSnapshot dataSnapshot) {
           mAnswer = (String) dataSnapshot.getValue(String.class);
       }

       [USER=1021285]@override[/USER]
       public void onCancelled(FirebaseError firebaseError) {

       }
   });
   mQuestionNo ++;

I want to randomize mQuestionNo object to retrieve random questions each time. Here is the structure of my firebase data

 

[Deleted User]

To get a random number between 1 and 50, use the following:

import java.util.Random;

Random rand = new Random();

int  n = rand.nextInt(50) + 1;