How to make a timer on my Android quiz application?

Question

I am making an Android quiz application and I would like for it to have a timer.. 15 seconds. When the timer finishes it moves to a new question. I really did not tried anything because I really don't have a clue, except a choronometer but it seems like a bad solution... the code:

I have added this code for a countdown... and you see when it finishes it goes to a method generateQuestion().. now it generates a new question but the answers are mixed up.. it shows answer from some other questions.. How do I solve this?

package com.matej.hajdukkviz;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import com.google.ads.AdRequest;
import com.google.ads.AdView;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class Glavno extends Activity implements OnClickListener {

int score  = 0;
int counter = 0;
boolean ajme = true;

TextView textView1, textView2, textView3, countdown;
Button btn1, btn2, btn3, btn4;

ArrayList<Question> qsts = new ArrayList<Question>();
List<Integer> generated = new ArrayList<Integer>();

ArrayList<String> allAnswers = new ArrayList<String>();

Random rng = new Random();
Question nextQuestion;

Question qjedan = new Question(
        "Q1",

        "Correct answer - q1",
        "Wrong answer 3 - q1",
        "Wrong answer 3 - q1",
        "Wrong answer 3 - q1"
        );
Question q2 = new Question(
        "Q2",

        "Correct answer - q2",
        "Wrong answer 3 - q2",
        "Wrong answer 3 - q2",
        "Wrong answer 3 - q2"
        );
Question q3 = new Question(
        "Q3",

        "Correct answer - q3",
        "Wrong answer 3 - q3",
        "Wrong answer 3 - q3",
        "Wrong answer 3 - q3"
        );


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.pitanja);

// ADD THE QUESTIONS IN THE ArrayList qsts

 new CountDownTimer(20000, 1000) {

         public void onTick(long millisUntilFinished) {
             textView4.setText("Seconds remaining: " + millisUntilFinished / 1000);
         }

         public void onFinish() {
             generateQuestion();
             textView2.setText("VRIJEME!");
             textView2.setTextColor(Color.RED);

         }
          }.start();

    qsts.add(qjedan);           
    qsts.add(q2);
    qsts.add(q3);

    textView1 = (TextView) findViewById(R.id.textView1);
    textView2 = (TextView) findViewById(R.id.textView2);
    textView3 = (TextView) findViewById(R.id.textView3);

    textView3.setText("Rezultat: " + score);

        btn1 = (Button) findViewById(R.id.btn1);
        btn2 = (Button) findViewById(R.id.btn2);
        btn3 = (Button) findViewById(R.id.btn3);
        btn4 = (Button) findViewById(R.id.btn4);

        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);
        btn4.setOnClickListener(this);

    generateQuestion();

}

    public void generateQuestion(){

        while(ajme = true){

            int nxt = rng.nextInt(3);

            if (!generated.contains(nxt)){

                generated.add(nxt);

                nextQuestion = qsts.get(nxt);

                textView1.setText(nextQuestion.questionText);

                allAnswers.add(nextQuestion.correctAnswerText);
                allAnswers.add(nextQuestion.wrongAnswer1);
                allAnswers.add(nextQuestion.wrongAnswer2);
                allAnswers.add(nextQuestion.wrongAnswer3);

                Collections.shuffle(allAnswers);

                btn1.setText(allAnswers.get(0));
                btn2.setText(allAnswers.get(1));
                btn3.setText(allAnswers.get(2));
                btn4.setText(allAnswers.get(3));

                break;
            }
        }
    }


    @Override
    public void onClick(View v) {
        Button b = (Button)v;
        String buttonText = b.getText().toString();

        if (counter == 3) {

            Intent theIntent = new Intent(this, Score.class);
            theIntent.putExtra("somename", score);  
            startActivity(theIntent);

            finish();   // Added this method call
        }

        else if(buttonText.equals(nextQuestion.correctAnswerText)) { 

            counter++;

            AdView ad = (AdView) findViewById(R.id.ads);
            ad.loadAd(new AdRequest());

            textView2.setText("TOČNO!");
            textView2.setTextColor(Color.GREEN);
            textView3.setText("Rezultat: " + (score += 10));

            allAnswers.clear();
            generateQuestion();

            return;
        } 

        else{

            counter++;

            AdView ad = (AdView) findViewById(R.id.ads);
            ad.loadAd(new AdRequest());

            textView2.setText("NETOČNO!");
            textView2.setTextColor(Color.RED);
            textView3.setText("Rezultat: " + (score -= 5));

            allAnswers.clear();
            generateQuestion();

            return; 
        }

    }   

}

Answer 1

I'm not going to write the code for you, however, in this situation I think you want a CountdownTimer . It is very easy to use. Here is the example from the docs.

 new CountDownTimer(30000, 1000) {

 public void onTick(long millisUntilFinished) {
     mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
 }

 public void onFinish() {
     mTextField.setText("done!");
 }
  }.start();

Basically, the onTick() will allow you to update a TextView with the seconds left or whatever (you also could do anything else you wanted to here). Then the onFinish() would allow you to, say, go to the next Activity

Here is an answer I gave that someone had issues with in case it helps.

Answer 2

Use a handler

private Handler mHandler = new Handler();

mHandler.removeCallbacks(mUpdateTimeTask);

mHandler.postDelayed(mUpdateTimeTask, 15000);

private Runnable mUpdateTimeTask = new Runnable() {
   public void run() {
       //do something
   }
};