title: Unable to add window android.view.ViewRoot$W@44da9bc0 -- permission denied for this window type
body: <p>I have prefer <a href="https://stackoverflow.com/questions/4481226/creating-a-system-overlay-always-on-top-button-in-android">this</a> post for example but I got the error at adding viewgroup into the windowmanager object, I have used the same class for the Service as posted into the question with no change where I can mistake I didn't gettting it</p>
  
  <pre><code>WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
  wm.addView(mView, params); // here
  </code></pre>
  
  <p>when I add view to the WindowManger</p>
  
  <p>here is my manifest file</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.searce.testoverlay"
        android:versionCode="1"
        android:versionName="1.0"&gt;
      &lt;uses-sdk android:minSdkVersion="7" /&gt;
  
      &lt;application android:icon="@drawable/icon" android:label="@string/app_name"&gt;
          &lt;activity android:name="TestOverlayActivity"
                        android:label="@string/app_name"&gt;
                  &lt;intent-filter&gt;
                      &lt;action android:name="android.intent.action.MAIN" /&gt;
                      &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
                  &lt;/intent-filter&gt;
              &lt;/activity&gt;
          &lt;service android:enabled="true" android:name=".HUD"&gt;&lt;/service&gt;
      &lt;/application&gt;
  &lt;/manifest&gt;
  </code></pre>
  
  <p>error</p>
  
  <pre><code>09-27 18:49:23.561: ERROR/AndroidRuntime(653): Uncaught handler: thread main exiting due to uncaught exception
  09-27 18:49:23.571: ERROR/AndroidRuntime(653): java.lang.RuntimeException: Unable to create service com.searce.testoverlay.HUD: android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRoot$W@44da9bc0 -- permission denied for this window type
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2790)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.app.ActivityThread.access$3200(ActivityThread.java:119)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1917)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.os.Handler.dispatchMessage(Handler.java:99)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.os.Looper.loop(Looper.java:123)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.app.ActivityThread.main(ActivityThread.java:4363)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at java.lang.reflect.Method.invokeNative(Native Method)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at java.lang.reflect.Method.invoke(Method.java:521)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at dalvik.system.NativeStart.main(Native Method)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653): Caused by: android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRoot$W@44da9bc0 -- permission denied for this window type
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.view.ViewRoot.setView(ViewRoot.java:492)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at com.searce.testoverlay.HUD.onCreate(HUD.java:41)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2780)
  09-27 18:49:23.571: ERROR/AndroidRuntime(653):     ... 10 more
  </code></pre>