title: Unable to start activity ComponentInfo...NullPointerException
body: <p>I am trying to populate a single listview with a textview but i am getting the following error on line 60 that is</p>
  
  <pre><code>    listView.setAdapter(adapter);                                
  </code></pre>
  
  <p>Here is my complete log.</p>
  
  <pre><code>04-16 10:51:38.953: E/AndroidRuntime(3068): FATAL EXCEPTION: main
  04-16 10:51:38.953: E/AndroidRuntime(3068): java.lang.RuntimeException: Unable to start activity ComponentInfo{}: java.lang.NullPointerException
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.os.Handler.dispatchMessage(Handler.java:99)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.os.Looper.loop(Looper.java:130)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.ActivityThread.main(ActivityThread.java:3687)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at java.lang.reflect.Method.invokeNative(Native Method)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at java.lang.reflect.Method.invoke(Method.java:507)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at dalvik.system.NativeStart.main(Native Method)
  04-16 10:51:38.953: E/AndroidRuntime(3068): Caused by: java.lang.NullPointerException
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at s..onCreate(Urgence.java:60)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
  04-16 10:51:38.953: E/AndroidRuntime(3068):     ... 11 more
  </code></pre>
  
  <p>This is my List class </p>
  
  <pre><code>public class ListClass extends Activity 
  {
  
  
  
      // Array of strings storing country names
      String[] countries = new String[] {
              "Services opposition", "Service Carte bancaire a l'etranger"
      };
  
      // Array of integers points to images stored in /res/drawable-ldpi/
      int[] flags = new int[]{
              R.drawable.arrow,
              R.drawable.arrow
      };
  
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) 
      {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.urgence);
  
          // Each row in the list stores country name, currency and flag
          List&lt;HashMap&lt;String,String&gt;&gt; aList = new ArrayList&lt;HashMap&lt;String,String&gt;&gt;();        
  
          for(int i=0;i&lt;2;i++){
              HashMap&lt;String, String&gt; hm = new HashMap&lt;String,String&gt;();
              hm.put("txt", countries[i]);
              hm.put("flag", Integer.toString(flags[i]) );            
              aList.add(hm);        
          }
  
          // Keys used in Hashmap
          String[] from = { "txt","flag"};
  
          // Ids of views in listview_layout
          int[] to = { R.id.single_text,R.id.single_image};        
  
          // Instantiating an adapter to store each items
          // R.layout.listview_layout defines the layout of each item
          SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), aList, R.layout.listview_layout, from, to);
  
          // Getting a reference to listview of main.xml layout file
          ListView listView = ( ListView ) findViewById(R.id.list);
  
          // Setting the adapter to the listView
          listView.setAdapter(adapter);                                
      }
  
  
  
  }
  </code></pre>
  
  <p>Anyone know why my adapter is null</p>
  
  <p><strong>Update :</strong> 
  This is my listview from my xml file</p>
  
  <pre><code>&lt;ListView 
      android:id="@android:id/list"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"/&gt;
  </code></pre>