remove black background of custom dialog
<p>as <img src="http://i.stack.imgur.com/ndZYE.jpg" alt="enter image description here"> ;</p>

<p>I want to remove the black the  background of  custom dialog,my code:</p>

<pre><code>public class MyAlertDialog extends AlertDialog { 
public MyAlertDialog(Context context) 
{  

    super(context); 
}  
public MyAlertDialog(Context context, int theme) 
{  super(context, theme); }

 }
</code></pre>

<p>in  activity to pop the dialog :</p>

<pre><code>public void showMyDialogOK(Context context,String s,DialogInterface.OnClickListener OkListener) {        
    MyAlertDialog myDialog = new MyAlertDialog(context, R.style.MyDialog2);        
    myDialog.setTitle(null); 
    myDialog.setMessage(s);        
    myDialog.setButton(DialogInterface.BUTTON_POSITIVE ,"Ok", OkListener);
    myDialog.show();    

}
</code></pre>

<p>my styles:</p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;resources&gt;
&lt;style name="MyTheme" parent="@android:style/Theme.NoTitleBar.Fullscreen"&gt;
        &lt;item name="android:alertDialogStyle"&gt;@style/AlertDialog&lt;/item&gt;  

&lt;/style&gt;    

 &lt;style name="MyTheme2" parent="@android:style/Theme.Black"&gt;
        &lt;item name="android:alertDialogStyle"&gt;@style/AlertDialog&lt;/item&gt;    
&lt;/style&gt; 

&lt;style name="AlertDialog"&gt;        
    &lt;item name="android:fullDark"&gt;@null&lt;/item&gt;
      &lt;item name="android:fullBright"&gt;@null&lt;/item&gt;
    &lt;item name="android:topDark"&gt;@drawable/popup_top_dark&lt;/item&gt;
       &lt;item name="android:topBright"&gt;@null&lt;/item&gt;
        &lt;item name="android:centerBright"&gt;@null&lt;/item&gt;
    &lt;item name="android:centerDark"&gt;@drawable/popup_center_dark&lt;/item&gt;
     &lt;item name="android:centerMedium"&gt;@null&lt;/item&gt;
    &lt;item name="android:bottomDark"&gt;@null&lt;/item&gt;
    &lt;item name="android:bottomBright"&gt;@null&lt;/item&gt;
    &lt;item name="android:bottomMedium"&gt;@drawable/popup_bottom_medium&lt;/item&gt;

&lt;/style&gt;

  &lt;style name="MyDialog2" parent="@android:Theme.Dialog"&gt;        
      &lt;item name="android:windowBackground"&gt;@null&lt;/item&gt;    
     &lt;item name="android:buttonStyle"&gt;@style/CustomButton&lt;/item&gt;  

  &lt;/style&gt;    

  &lt;style name="CustomButton" parent="@android:style/Widget.Button"&gt;        
       &lt;item name="android:background"&gt;@drawable/button_stateful&lt;/item&gt;  
 &lt;/style&gt;
 &lt;/resources&gt;
</code></pre>

<p>popup_center_dark.9.png  as:</p>

<p><img src="http://i.stack.imgur.com/EVldj.png" alt="popup_center_dark.9.png"></p>

<p>popup_bottom_medium.9.png  as:</p>

<p><img src="http://i.stack.imgur.com/F5UJf.png" alt="popup_bottom_medium.9.png"></p>

<p>popup_top_dark.9.png    as:</p>

<p><img src="http://i.stack.imgur.com/mtuQA.png" alt="popup_top_dark.9.png"></p>

<p>if you run my code you will found my dialog have a black background, it is not the app background,</p>
