Using multidimensional-array in Android

Question

Here is my edited code:

package com.gamesup.braingame;

import java.util.Random;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Easy extends Activity implements OnClickListener{

EditText display;
// This Array says , I am an array that holds arrays
String [][] multiArray = {{"4 + 5", "9"},     
        {"20 * 3","60"},
        {"99 - 9","90"}};  
TextView displayExpression;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.easy);

    display = (EditText)findViewById(R.id.displayText);
    display.setText("?");

    displayExpression = (TextView) findViewById(R.id.expression);
    Button generate = (Button) findViewById(R.id.random_gen);

    generate.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            Random ranGenerate = new Random ();
            int random = ranGenerate.nextInt(4) ;
            // Fetch your random question
            String Rquestion = multiArray[random][0];
            displayExpression.setText(Rquestion);

        }
    });

}

static boolean isEmpty = true;

public void num_Clicked(View v){
    Button btn = (Button) findViewById(v.getId());
    //getting the button object and using a view to get the id of the buttons

     if (v.getId()== R.id.del_button){
            String s = display.getText().toString();
            s = s.substring(0, s.length() - 1);
            display.setText(s);
            return;
     }


    if(isEmpty){
        display.setText(btn.getText());
        isEmpty = false;
    }
    else{
        display.append(btn.getText().toString()); 
    }



}

public void hash_Clicked(View v){

    if (v.getId()== R.id.hash_button){


         // Get the Answer from your EditText
         String answer =  display.getText().toString();

         // Using a for loop iterate on the base index
         for(int i = 0; i < multiArray.length ; i++)
         {
              // if the answer is in position 1 of Array [i] 
              if(answer.equals(multiArray[i][1]))
              {
                // We have found the answer, Congratulate the User 
                  displayExpression.setText("CORRECT");

              }else{
                  displayExpression.setText("INCORRECT");

              }

         }

    }

}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}


}

After the user enters the wrong answer and clicks the random generator button (random_gen) again my app closes with an error. Does this have anything to do with the multiArray being created in the onClick method? What would i have to do to resolve this?

EDIT:

Now when i press the hash button it does not display correct, Do i have to add a different if statement for each position?

I suggest you accept one of the answers, and formulate a new question with the matter of the display of your hash button. — njzk2
– njzk2, Commented Feb 20, 2014 at 22:33

Melquiades · Accepted Answer · 2014-02-20 22:24:35Z

1

Your ranGenerate will generate integers from 0 to 3, and your array indexes go from 0 to 2, so if random happens to be 3, you get an exception.

Change the maximal generated integer to 2 with the following:

int random = ranGenerate.nextInt(3);  //this generates integers from 0 to 2

or even better - use the length of your array, so that if you add more to it later, you won't have to change the random generation code:

int random = ranGenerate.nextInt(multiArray.length);

answered Feb 20, 2014 at 22:24

Melquiades

8,5981 gold badge36 silver badges48 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

sumr Over a year ago

Thanks :) didn't see that. But now when i press the hash button it does not display CORRECT even if the answer is correct, Do i have to add a different if statement for each position? It displays INCORRECT each time.

Prakash · Accepted Answer · 2014-02-20 22:21:20Z

0

 Random ranGenerate = new Random ();
 int random = ranGenerate.nextInt(4) ;

nextInt(4) can give values range 0 - 3. and your array have values from 0 - 2.

Change to int random = ranGenerate.nextInt(3) or add another item to array.

answered Feb 20, 2014 at 22:21

Prakash

4,63733 silver badges42 bronze badges

1 Comment

sumr Over a year ago

Thanks :) didn't see that. But now when i press the hash button it does not display CORRECT even if the answer is correct, Do i have to add a different if statement for each position?

Collectives™ on Stack Overflow

Using multidimensional-array in Android

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related