Android soft Keyboard not open in webView`

I m Using WebView in AlertDialog to authenticate user to twitter. but When i click on field in webview ,android keyboard doesnt open. here is my code that shows how i added webview in alert dialog. i implicitly call android keyboard but it open keyboard behind alert dialog.

here is my code.

public static void webViewDialog(final String authorizationURL, final int type)
{

    final boolean correctPin;
    System.out.println("In webViewDialog");
    container = new LinearLayout(context);
    container.setOrientation(LinearLayout.VERTICAL);

    container.setMinimumWidth(200);
    container.setMinimumHeight(320); 

    webView = new WebView(context);
    webView.setMinimumWidth(200);
    webView.requestFocusFromTouch();
    webView.setMinimumHeight(380);
    webView.getSettings().setJavaScriptEnabled(true);
    webView.setWebViewClient(new TwitterWebViewClient());
    webView.loadUrl(authorizationURL);
    webView.setBackgroundColor(0xFFbbd7e9);
    container.addView(webView);

    Builder webDialog = new AlertDialog.Builder(context);

    webDialog.setView(container).setTitle("Twitter Login")
            .setPositiveButton("Ok", new DialogInterface.OnClickListener()
        {

                @Override
                public void onClick(DialogInterface dialog, int which) 
                {

                    if (type == 0) 
                    {
                          twitterPinCodeDialog();
                        dialog.dismiss();

                    }
                }
        }).show();
    showVirtualKeyboard();

}
public static void showVirtualKeyboard()
{
    Timer timer = new Timer();
    timer.schedule(new TimerTask()
    {

         @Override
         public void run()
         {
              InputMethodManager m = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);

              if(m != null)
              {
                // m.toggleSoftInput(0, InputMethodManager.HIDE_NOT_ALWAYS);