how can i link my keypad button to the answer of random expression
<p>i have created random expression and want to link their answers to the keypad on screen, so that if the randon question is 3+2=? then when i press the keypad_five then it displays the number 5 on the screen like 3+2=5.</p>

<p>my .xml code is </p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" &gt;

    &lt;TextView
        android:id="@+id/Guess"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="15dp"
        android:text="Guess : "
        android:textSize="25dp" /&gt;
    &lt;TextView
        android:id="@+id/Title"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="15dp"
        android:textSize="25dp" /&gt;
    &lt;TextView
        android:id="@+id/Answer"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="15dp"
        android:textSize="25dp" /&gt;



&lt;TextView
        android:id="@+id/INCORRECT"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" /&gt;
    &lt;TextView
        android:id="@+id/CORRECT"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="40dp"/&gt;

&lt;TableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/keypad"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:stretchColumns="*" &gt;
&lt;TableRow&gt;
&lt;Button android:id="@+id/keypad_1"
android:text="1" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_2"
android:text="2" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_3"
android:text="3" &gt;
&lt;/Button&gt;
&lt;/TableRow&gt;
&lt;TableRow&gt;
&lt;Button android:id="@+id/keypad_4"
android:text="4" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_5"
android:text="5" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_6"
android:text="6" &gt;
&lt;/Button&gt;
&lt;/TableRow&gt;
&lt;TableRow&gt;
&lt;Button android:id="@+id/keypad_7"
android:text="7" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_8"
android:text="8" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_9"
android:text="9" &gt;
&lt;/Button&gt;
&lt;/TableRow&gt;

&lt;TableRow&gt;
    &lt;Button android:id="@+id/delete"
android:text="DEL" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_0"
android:text="0" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_hash"
android:text="#" &gt;
&lt;/Button&gt;
&lt;Button android:id="@+id/keypad_subtract"
android:text="-" &gt;
&lt;/Button&gt;
&lt;/TableRow&gt;
&lt;/TableLayout&gt;


    &lt;TextView
        android:id="@+id/INCORRECT"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" /&gt;
    &lt;TextView
        android:id="@+id/CORRECT"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="40dp"/&gt;

&lt;/LinearLayout&gt;
</code></pre>

<p>.Java code is </p>

<pre><code>package org.example.question;

import java.util.Random;


import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class QuestionActivity extends Activity implements View.OnClickListener {
    /** Called when the activity is first created. */

    //variable for different questions
    int fnum0, snum0,fnum1, snum1,fnum2, snum2,fnum3, snum3,
    fnum4, snum4,fnum5, snum5,fnum6, snum6,fnum7, snum7,
    fnum8, snum8,fnum9, snum9, answer;


    //variable and type declaration for buttons and text
Button keyOne;
Button keyTwo;
Button keyThree;
Button keyFour;
Button keyFive;
Button keySix;
Button keySeven;
Button keyEight;
Button keyNine;
Button keyDel;
Button keyZero;
Button keyHash;
Button keySubtract;
TextView display;
TextView display1;
TextView answer0;
int question=0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);  

        //display text on screen

        display1 = (TextView)findViewById(R.id.Guess);
        display = (TextView)findViewById(R.id.Title);
        answer0 = (TextView)findViewById(R.id.Answer);

        ///Code for correct and incorrect

        //assigning names to each keypad
        keyOne= (Button) findViewById(R.id.keypad_1);
        keyTwo= (Button) findViewById(R.id.keypad_2);
        keyThree= (Button) findViewById(R.id.keypad_3);
        keyFour= (Button) findViewById(R.id.keypad_4);
        keyFive = (Button) findViewById(R.id.keypad_5);
        keySix= (Button) findViewById(R.id.keypad_6);
        keySeven = (Button) findViewById(R.id.keypad_7);
        keyEight = (Button) findViewById(R.id.keypad_8);
        keyNine = (Button) findViewById(R.id.keypad_9);
        keyZero = (Button) findViewById(R.id.keypad_0);
        keySubtract = (Button) findViewById(R.id.keypad_subtract);
        keyHash = (Button) findViewById(R.id.keypad_hash);
        keyDel = (Button) findViewById(R.id.delete);

        //setting button to produce an event when each button is pressed
        keyOne.setOnClickListener(this);     keyTwo.setOnClickListener(this);     keyThree.setOnClickListener(this); 
        keyFour.setOnClickListener(this);    keyFive.setOnClickListener(this);     keySix.setOnClickListener(this);     
        keySeven.setOnClickListener(this);    keyEight.setOnClickListener(this);  keyNine.setOnClickListener(this);    
        keySubtract.setOnClickListener(this);   keyHash.setOnClickListener(this);  keyDel.setOnClickListener(this);

}

    public void onClick(View arg0) {



        switch(arg0.getId()){   
        case R.id.keypad_hash:

            //Generates random numbers
            fnum0 = (int) ((double) ((Math.random() * 10))); 
            snum0 = (int) ((double) ((Math.random() * 10))); 
            String str = ""; 

            //genrates random number between 0 to 9
            int operation = (int) ((double) ((Math.random() * 10))); 


            if(operation == 0)  
               str = fnum0+  "+"  +  snum0+  "="; 
            if("CORRECT".equals(display.getText().toString()))
            else if(operation == 1) 
               str = fnum0 +  "-"  +  snum0+  "="; 
            else if(operation == 2)  
               str = fnum0 +  "*"  +  snum0+  "="; 
            else  
               str = fnum0 +  "/"  +  snum0+  "="; 

            display.setText(str); 

            break;





        }   
     }
    public void requestFocus() {
        // TODO Auto-generated method stub

    }
}
</code></pre>

<p>but when i insert than "CORRECT" line the question dont show up neither to the answer          </p>
