Q:

Android app - Unfortunately Stops

I am a Beginner am writing a code of listView that perform an action
on OnclickListner..But it gives error "Unfortunately Stops". I want to perform different action on selecting different list items. Im new to android development so im following basic tutorials online.
I've got this switch/case structure:
package com.list;

import android.os.Bundle;    
import android.app.ListActivity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.CheckedTextView;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends ListActivity {

    final int Aatma = 0; //should be equal to the index in your array.
    final int Special26 = 1;
    final int Dabangg2 = 2;

    String menu[] = {"Aatma","Special26","Dabangg2" };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       // ListView l = (ListView)findViewById(R.id.list);
        setListAdapter(new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1,menu));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
    protected void onListItemClick(ListView l, View v, int position, long id) {

        // super.onListItemClick(l, v, position, id);

       CheckedTextView selectedItem = (CheckedTextView) v;
       boolean isChecked = selectedItem.isChecked();
       Log.e("TAG","item clicked position = " + position + " isChecked = " + isChecked);

        switch (position) {
        case Aatma:
            Toast.makeText(this, "AAtma !", Toast.LENGTH_LONG).show();

            break;
        case Special26:
            Toast.makeText(this, "Special26 !", Toast.LENGTH_LONG).show();

            break;

        case Dabangg2:
            Toast.makeText(this, "Dabangg 2 !", Toast.LENGTH_LONG).show();

            break;
        default:
            break;
        }

    }

}

Error Log-
04-29 18:28:21.514: W/dalvikvm(782): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-29 18:28:21.544: E/AndroidRuntime(782): FATAL EXCEPTION: main
04-29 18:28:21.544: E/AndroidRuntime(782): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.list/com.list.MainActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.os.Looper.loop(Looper.java:137)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread.main(ActivityThread.java:5041)
04-29 18:28:21.544: E/AndroidRuntime(782):  at java.lang.reflect.Method.invokeNative(Native Method)
04-29 18:28:21.544: E/AndroidRuntime(782):  at java.lang.reflect.Method.invoke(Method.java:511)
04-29 18:28:21.544: E/AndroidRuntime(782):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-29 18:28:21.544: E/AndroidRuntime(782):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-29 18:28:21.544: E/AndroidRuntime(782):  at dalvik.system.NativeStart.main(Native Method)
04-29 18:28:21.544: E/AndroidRuntime(782): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ListActivity.onContentChanged(ListActivity.java:243)
04-29 18:28:21.544: E/AndroidRuntime(782):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:273)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.Activity.setContentView(Activity.java:1881)
04-29 18:28:21.544: E/AndroidRuntime(782):  at com.list.MainActivity.onCreate(MainActivity.java:25)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.Activity.performCreate(Activity.java:5104)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-29 18:28:21.544: E/AndroidRuntime(782):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-29 18:28:21.544: E/AndroidRuntime(782):  ... 11 more

A:

Your layout needs to contain a listview with id android.R.id.list like so:
<ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

Important is that the id is @android:id/list as explained in http://developer.android.com/reference/android/app/ListActivity.html (see section "screen layout").

