title: spinning wheel for webview
body: <p>I want to set spinning wheel for the webview till when the page is loaded , i am using the following approach but its floating with following logcat errors . Please guide </p>
  
  <pre><code>public class Webview extends Activity {
    WebView mWebView;
  
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  
      this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
  
  
      // Makes Progress bar Visible
  
  
  
      getWindow().requestFeature(Window.FEATURE_PROGRESS);
  
      WebView mWebView = (WebView) findViewById(R.id.webview);
  
      mWebView.getSettings().setJavaScriptEnabled(true);
  
      final Activity activity = this;
  
      mWebView.setWebChromeClient(new WebChromeClient(){
  
               public void onProgressChanged(WebView view, int progress) {
                       activity.setTitle("Loading...");
                       activity.setProgress(progress * 100);
                          if(progress == 100)
                             activity.setTitle("My title");
                       }
      });
  
      mWebView.loadUrl("..........................");
  
      mWebView.setVerticalScrollBarEnabled(false);
      mWebView.setHorizontalScrollBarEnabled(false);
  
  }
  </code></pre>
  
  <p>xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  
      &lt;WebView  xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/webview"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
  
  /&gt;
  </code></pre>
  
  <p>logcat</p>
  
  <pre><code>07-10 17:49:18.785: DEBUG/AndroidRuntime(23772): Shutting down VM
  07-10 17:49:18.785: WARN/dalvikvm(23772): threadid=3: thread exiting with uncaught exception (group=0x4001e390)
  07-10 17:49:18.785: ERROR/AndroidRuntime(23772): Uncaught handler: thread main exiting due to uncaught exception
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.droidnova.android.howto.optionmenu/com.droidnova.android.howto.optionmenu.Webview}: java.lang.NullPointerException
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2596)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2621)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread.access$2200(ActivityThread.java:126)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1932)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.os.Handler.dispatchMessage(Handler.java:99)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.os.Looper.loop(Looper.java:123)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread.main(ActivityThread.java:4595)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at java.lang.reflect.Method.invokeNative(Native Method)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at java.lang.reflect.Method.invoke(Method.java:521)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at dalvik.system.NativeStart.main(Native Method)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772): Caused by: java.lang.NullPointerException
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at com.droidnova.android.howto.optionmenu.Webview.onCreate(Webview.java:36)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2544)
  07-10 17:49:18.795: ERROR/AndroidRuntime(23772):     ... 11 more
  </code></pre>