moja pierwsza aktywność Xm

  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="#a5c63b"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      tools:context=".MainActivity" >
<Button
    android:id="@+id/btn1"
    android:layout_width="match_parent"
    android:layout_height="70dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="70dp"
    android:background="#434d23"
    android:text="Ok To Continue"
    android:onClick="frontt"
    android:textColor="#a5c63b" />
<ImageView
    android:id="@+id/imageView11"
    android:layout_width="250dp"
    android:layout_height="250dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:src="@drawable/question" />
<TextView
    android:id="@+id/txtview11"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="Loading..."
    android:textSize="12dp" />
  </RelativeLayout>

To jest moja druga aktywność Xml

  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="#a5c63b"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
     tools:context=".MainActivity" >

<Button
    android:id="@+id/btn"
    android:layout_width="match_parent"
    android:layout_height="70dp"
     android:onClick="onClick"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="70dp"
    android:background="#434d23"
    android:text="OK"
    android:textColor="#a5c63b" />

<EditText
    android:id="@+id/txtedit"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:layout_alignLeft="@+id/button1"
    android:layout_alignParentTop="true"
    android:layout_marginTop="50dp"
    android:background="#edf2db"
    android:ems="10"
    android:inputType="numberDecimal" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="250dp"
    android:layout_height="250dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:src="@drawable/question" />

<TextView
    android:id="@+id/txtview"
    android:layout_width="match_parent"
    android:layout_height="20dp"
    android:layout_alignBottom="@+id/txtedit"
    android:layout_alignLeft="@+id/txtedit"
    android:layout_marginBottom="21dp"
    android:text="Guess Single Digit Number"
    android:textSize="12dp" />

<TextView
    android:id="@+id/txtview2"
   android:layout_width="match_parent"
    android:layout_height="20dp"
    android:layout_alignLeft="@+id/btn"
    android:layout_below="@+id/btn"
    android:text="TextView" />

 </RelativeLayout>

to jest mój pierwszy kod java

   package com.example.game;
   import android.media.MediaPlayer;
   import android.os.Bundle;
   import android.view.View;
   import android.view.View.OnClickListener;
    import android.app.Activity;
   import android.content.Intent;
     import android.view.Menu;
    import android.widget.Button;


public class MainActivity extends Activity {
  MediaPlayer btnsound;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.front);
    Button next = (Button) findViewById(R.id.btn1);


    btnsound = MediaPlayer.create(MainActivity.this,R.raw.game);
    btnsound.start();




    next.setOnClickListener(new OnClickListener()
{
    public void onClick(View v)
    {

        Intent nextScreen = new Intent(getApplicationContext(), CopyOfMainActivity.class);

        startActivity(nextScreen);
        //finish();
    }
 } );

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}        
  }

to jest mój drugi plik java

   package com.example.game;
   import java.util.Random;
    import android.media.MediaPlayer;
    import android.os.Bundle;
   import android.view.View;
   import android.view.View.OnClickListener;
   import android.widget.Button;
   import android.widget.EditText;
   import android.widget.ImageView;
   import android.widget.TextView;
  import android.app.Activity;
  import android.view.Menu;

 public class CopyOfMainActivity extends Activity {
MediaPlayer btnsound;
Random random = new Random();
int randnumber = random.nextInt(10);
Button b2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    btnsound = MediaPlayer.create(CopyOfMainActivity.this,R.raw.game);
    btnsound.start();
    b2= (Button) findViewById(R.id.btn);
    b2.setOnClickListener(new OnClickListener()
{
    public void onClick(View v)
    {

         EditText input = (EditText)findViewById(R.id.txtedit);
         TextView resultText = (TextView) findViewById(R.id.txtview2);
         String inputstring = input.getText().toString();
            int number = Integer.parseInt(inputstring);    
          if(randnumber==number)
          {
              resultText.setText("you win" );
              ImageView image = (ImageView) findViewById(R.id.imageView1);
                image.setImageResource(R.drawable.win);
          }
          else if (number>randnumber)
          {

              resultText.setText("you guess high number" );
              ImageView image = (ImageView) findViewById(R.id.imageView1);
                image.setImageResource(R.drawable.tryagain);
          }
          else if (number<randnumber)
          {

              resultText.setText("you guess low number" );
              ImageView image = (ImageView) findViewById(R.id.imageView1);
                image.setImageResource(R.drawable.lose);
          }
    }
 } );

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}       
}

Mam jeden przycisk na pierwszym układzie xml. Pierwsze wyświetlenie układu aktywności po uruchomieniu aplikacji, ale gdy klikam przycisk na pierwszym xml, najpierw chcę przejść do następnego laytoutu po kliknięciu, ten błąd pojawia się na karcie LogCat i aplikacja przestaje działać.

AndroidRuntime at dalvik.system.NativeStart.main (Metoda natywna)

Co powinienem zrobić?