Question

as soon as I use method Game(), my app crashes, why?
Also I’d like to know if it’s possible to make my code shorter in terms of space it takes & better.

Code:

package com.aleksei.etb;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;

public class ETBetaActivity extends Activity implements View.OnClickListener {

    Button answer_1,
    answer_2,answer_3,
    answer_4,main;

    TextView q_textview,
    TextView tip;

    private String aString[];

    private int i1 = 0;
    private int correct = 0;

    private boolean alive = false;

    MediaPlayer button_click;

    private String[] questions ={"Question 1" , "Question 2","Question 5"};
    private String[] answers_correct ={"Correct answer 1", "Correct answer 2","Correct answer 3","Correct answer 4","Correct answer 5"};

    List<String> question_list = new ArrayList<String>();
    List<String> answer_list_correct = new ArrayList<String>();


    @Override
    public void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            getData();
    }

    @Override
    public void onClick(View view) {

        button_click = MediaPlayer.create(this, R.raw.button_click);
        button_click.start();
        switch(view.getId()){

           case R.id.button5: //main
                             if(!alive)
                             alive = true;
                             break;
           case R.id.button1: //answer_1
                             if(alive == false)
                               return;
                             if(correct(1))
                               correct++;           
                             break;
           case R.id.button2: //answer_2
                             if(alive == false)
                               return;
                             if(correct(2))
                               correct++;
                             break;
           case R.id.button3: //answer_3
                             if(alive == false)
                               return;
                             if(correct(3))
                               correct++;           
                             break;
           case R.id.button4: //answer_3
                             if(alive == false)
                               return;
                             if(correct(4))
                               correct++;
                             break;
               default:
                             break;     
           }
           Game();      
    }

    private boolean correct(int button){

       try {
            for (int i = 0; i < answers_correct.length; i++){
                 if(button == 1 && aString[0] == answers_correct[i]
            || button == 2 && aString[1] == answers_correct[i]
            || button == 3 && aString[2] == answers_correct[i]
            || button == 4 && aString[3] == answers_correct[i])
                        return true;
            }
       } 
       catch(Exception ex){
            System.out.println(ex);
       }
       return false;
    }

    private void Game(){

        if(i1 > questions.length) //no more questions
            return;
        main.setText("Next");
            try {
                    String answer_list[][] = {
                               {answers_correct[i1], "Answer 1-2" , "Answer 1-3" , "Answer 1-4"},
                               {answers_correct[i1], "Answer 2-2" , "Answer 2-3" , "Answer 2-4"},
                               {answers_correct[i1], "Answer 3-2" , "Answer 3-3" , "Answer 3-4"},
                               {answers_correct[i1], "Answer 4-2" , "Answer 4-3" , "Answer 4-4"},
                               {answers_correct[i1], "Answer 5-2" , "Answer 5-3" , "Answer 5-4"}};

                    Collections.shuffle(Arrays.asList(answer_list[i1]));
                    answer_1.setText(answer_list[i1][0]);
                    answer_2.setText(answer_list[i1][1]);
                    answer_3.setText(answer_list[i1][2]);
                    answer_4.setText(answer_list[i1][3]);
                    aString[0] = answer_list[i1][0];
                    aString[1] = answer_list[i1][1];
                    aString[2] = answer_list[i1][2];
                    aString[3] = answer_list[i1][3];
                    q_textview.setText(questions[i1]);
          } 
          catch(Exception e){
            System.out.println(e);
          }
          tip.setText(correct);

        /*questions = question_list.toArray(new String[question_list.size()]);
         answers_correct = answer_list_correct.toArray(new                  String[answer_list_correct.size()]);

        question.setText(questions[i1]);        

        answer_list_correct.remove(questions[i1]);
        question_list.remove(questions[i1]);*/
         i1++;
    }
    private void getData(){
        //Getting the data
        main = (Button) findViewById(R.id.button5);
        answer_1 = (Button) findViewById(R.id.button1);
        answer_2 = (Button) findViewById(R.id.button2);
        answer_3 = (Button) findViewById(R.id.button3);
        answer_4 = (Button) findViewById(R.id.button4);
        q_textview = (TextView) findViewById(R.id.question);
        tip = (TextView) findViewById(R.id.answ1);

        //Making the buttons, actually work
        main.setOnClickListener(this);
        answer_1.setOnClickListener(this);
        answer_2.setOnClickListener(this);
        answer_3.setOnClickListener(this);
        answer_4.setOnClickListener(this);

            //Resets the text
            //Note to self: Replace with another ContectView
        main.setText("Begin!");
        answer_4.setText("");
        answer_3.setText("");
        answer_2.setText("");
        answer_1.setText("");

    /*  for(String x : questions) {
            for(String y : answers_correct){

            answer_list_correct.add(y);
            question_list.add(x);

            Collections.shuffle(answer_list_correct);
            Collections.shuffle(question_list);

            }
        } */
    }
}

Best regards.

Answer 1

In Game(), you check i1 > questions.length at the top, but try q_textview.setText(questions[i1]); near the bottom. If i1 == questions.length, that would throw an ArrayIndexOutOfBoundsException (hope I remembered the name correctly), make it i1 >= questions.length. Also, you use i1 as index for answers_correct and answer_list, that won’t be out of bounds for the pasted questions and answers_correct, but might be for the real (unlikely, though, you won’t have more questions than answers, would you?).

In correct, your if statement

if(button == 1 && aString[0] == answers_correct[i]
    || button == 2 && aString[1] == answers_correct[i]
    || button == 3 && aString[2] == answers_correct[i]
    || button == 4 && aString[3] == answers_correct[i])
    return true;

could be shortened to

if (aString[button-1] == answers_correct[i]) return true;

(unless button can have values < 1 or > 4, then you would need to check for button >= 1 && button <= 4 too). However, using == to compare Strings is dangerous and almost certainly wrong. == compares the equality of references, so string1 == string2 is true only if both refer to the same String instance. If, as seems to be the case, all your Strings come from string literals in the source code, it will kind of work because then there is only one instance for each literal, but if outside Strings could enter the game, you must use equals to compare Strings. Use equals also in those cases where == would (sort of accidentally) work.