i followed a YouTube tutorial about programming a quiz app using java android studio in the tutorial you put the question in array list then you get randomly question from it this can cause a problem of getting the same question many time. How can i fix that? i thought about instead of using random i use a function to get the next item in the list but it didn't work for me. Yhis is my code

package com.example.quiz20;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.google.android.material.bottomsheet.BottomSheetDialog;

import java.util.ArrayList;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private TextView questionTV,questionNumberTV;
    private Button option1Btn,option2Btn,option3Btn,option4Btn;
    private ArrayList<QuizModel> quizModelArrayList;
    Random random;
    int currentScore = 0 , questionAttempted = 0, currentPos;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        questionTV= findViewById(R.id.idTVQuestion);
        questionNumberTV=findViewById(R.id.idTVQuestionAttempted);
        option1Btn=findViewById(R.id.idBtnOption1);
        option2Btn=findViewById(R.id.idBtnOption2);
        option3Btn=findViewById(R.id.idBtnOption3);
        option4Btn=findViewById(R.id.idBtnOption4);
        quizModelArrayList = new ArrayList<>();
        random = new Random();
        getQuizQuestion(quizModelArrayList);
        currentPos = random.nextInt(quizModelArrayList.size());
        setDataToViews(currentPos);
        option1Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(quizModelArrayList.get(currentPos).getAnswer().trim().toLowerCase().equals(option1Btn.getText().toString().trim().toLowerCase())){
                    currentScore  ;
                }
                questionAttempted  ;
                currentPos = random.nextInt(quizModelArrayList.size());
                setDataToViews(currentPos);

            }
        });

        option2Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(quizModelArrayList.get(currentPos).getAnswer().trim().toLowerCase().equals(option2Btn.getText().toString().trim().toLowerCase())){
                    currentScore  ;
                }
                questionAttempted  ;
                currentPos = random.nextInt(quizModelArrayList.size());
                setDataToViews(currentPos);
            }
        });

        option3Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(quizModelArrayList.get(currentPos).getAnswer().trim().toLowerCase().equals(option3Btn.getText().toString().trim().toLowerCase())){
                    currentScore  ;
                }
                questionAttempted  ;
                currentPos = random.nextInt(quizModelArrayList.size());
                setDataToViews(currentPos);
            }
        });

        option4Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(quizModelArrayList.get(currentPos).getAnswer().trim().toLowerCase().equals(option4Btn.getText().toString().trim().toLowerCase())){
                    currentScore  ;
                }
                questionAttempted  ;
                currentPos = random.nextInt(quizModelArrayList.size());
                setDataToViews(currentPos);
            }
        });

    }

    private void showBottomSheet(){
        BottomSheetDialog bottomSheetDialog = new BottomSheetDialog(MainActivity.this);
        View bottomSheetView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.score_bottom_sheet,(LinearLayout)findViewById(R.id.idLLScore));
        TextView scoreTV = bottomSheetView.findViewById(R.id.idTVScore);
        Button restartQuizBtn = bottomSheetView.findViewById(R.id.idBtnRestart);
        scoreTV.setText("you score is \n" currentScore   "/4");
        restartQuizBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                currentPos = random.nextInt(quizModelArrayList.size());
                setDataToViews(currentPos);
                questionAttempted = 0;
                currentScore = 0;
                bottomSheetDialog.dismiss();
            }
        });
        bottomSheetDialog.setCancelable(false);
        bottomSheetDialog.setContentView(bottomSheetView);
        bottomSheetDialog.show();
    }

    private void setDataToViews(int currentPos){
        questionNumberTV.setText("Question Attempted : " questionAttempted   "/4");
        if(questionAttempted == 4){
            showBottomSheet();
        }else {
            questionTV.setText(quizModelArrayList.get(currentPos).getQuestion());
            option1Btn.setText(quizModelArrayList.get(currentPos).getOption1());
            option2Btn.setText(quizModelArrayList.get(currentPos).getOption2());
            option3Btn.setText(quizModelArrayList.get(currentPos).getOption3());
            option4Btn.setText(quizModelArrayList.get(currentPos).getOption4());
        }


    }
    private void getQuizQuestion(ArrayList<QuizModel> quizModelArrayList) {
        quizModelArrayList.add(new QuizModel("in which year google released?","1998","2000","2004","1995","1998"));
        quizModelArrayList.add(new QuizModel("What does CPU stand for?","Core Processing Unit","Central Processing Unit","Command Processing Unit","Custom Processing Unit","Central Processing Unit"));
        quizModelArrayList.add(new QuizModel("what is the name of the first internet search engine?","Google","Yahoo","AOL","Archie","Archie"));
        quizModelArrayList.add(new QuizModel("Which Programming language is the most widely used?","JavaScript","JAVA","Python","PHP","JavaScript"));

    }
}

CodePudding user response：

To avoid getting the same selection multiple times, you may want to remove it from the list after it was chosen. The syntax could look something like this:

    Random rand = new Random();
    ArrayList <Type> listName = new ArrayList<>();
    int selection = rand.nextInt(listName.size()   1);

    switch(selection)
    {
        case X:
            do the X stuff;
            listName.remove(X);
            break;
    }

The ArrayList knows what index X is at, so calling it by name will remove the entry. Using the size of the ArrayList to create the bounds for Random numbers also helps keep it dynamic

NOTE this is NOT complete code

CodePudding user response：

You can drop the question from the array list and make the random number 1 smaller each time. You have to make sure the list can be reset and is automatically reset when it gets to 0 if you do this.