title: Clicking spinner within popup window causes WindowManager$BadTokenException
body: <p>I've looked up a couple of posts for the same problem but can't seem to resolve my issue. I've used spinners throughout my application and they are working fine. It's when I try to use a spinner within a popupwindow, I get an error when selecting it. The popup window is to add references and I've declared a global ViewGroup variable (i.e. vg_references) which can be used to retrieve the components on the popup window. The code to popup the window is as follows. </p>
  
  <pre><code>LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  vg_references = (ViewGroup)inflater.inflate(R.layout.reference, null, false);
  
  pw_references = new PopupWindow(vg_references, 
      this.getWindowManager().getDefaultDisplay().getWidth()/100 * 75,
      this.getWindowManager().getDefaultDisplay().getHeight()/100 * 50,
      true);
  pw_references.setFocusable(true);
  pw_references.showAtLocation((View)view.getParent(), Gravity.CENTER, 0, 0);
  
  this.populateReferenceView();   
  </code></pre>
  
  <p>This then calls a function to populate the components within the popupwindow (e.g. textfields, spinners, layouts, etc...). Part of this function is to populate a spinner with a list of strings from a database.</p>
  
  <pre><code>// Find the spinner
  Spinner spinReferenceSourceTypes = (Spinner) vg_references.findViewById(R.id.spin_referencesSourceTypes);          
  
  // Retrieve the list of reference source types and create an array adapter to attach to the list 
  ArrayAdapter&lt;String&gt; dataAdapter = new ArrayAdapter&lt;String&gt;(
      this, android.R.layout.simple_spinner_item, databaseHelper.getReferenceSourceTypes());
  dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  spinReferenceSourceTypes.setAdapter(dataAdapter);
  
  // If there's only 1 item in the dropdown list, disable the dropdown list
  if(spinReferenceSourceTypes.getCount() &lt; 2) {
      spinReferenceSourceTypes.setEnabled(false);
  }
  else {
      spinReferenceSourceTypes.setEnabled(true);
  }
  </code></pre>
  
  <p>When I click on this spinner, the program crashes with the following error. Can anyone please help me with this problem. Thank you all</p>
  
  <pre><code>12-04 18:43:41.507: E/AndroidRuntime(30504): FATAL EXCEPTION: main
  12-04 18:43:41.507: E/AndroidRuntime(30504): android.view.WindowManager$BadTokenException: Unable to add window -- token android.view.ViewRootImpl$W@414c67c8 is not valid; is your activity running?
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.ViewRootImpl.setView(ViewRootImpl.java:520)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:313)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.Window$LocalWindowManager.addView(Window.java:537)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.widget.PopupWindow.invokePopup(PopupWindow.java:992)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.widget.PopupWindow.showAsDropDown(PopupWindow.java:901)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.widget.ListPopupWindow.show(ListPopupWindow.java:595)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.widget.Spinner$DropdownPopup.show(Spinner.java:764)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.widget.Spinner.performClick(Spinner.java:457)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.view.View$PerformClick.run(View.java:14152)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.os.Handler.handleCallback(Handler.java:605)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.os.Handler.dispatchMessage(Handler.java:92)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.os.Looper.loop(Looper.java:137)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at android.app.ActivityThread.main(ActivityThread.java:4514)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at java.lang.reflect.Method.invokeNative(Native Method)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at java.lang.reflect.Method.invoke(Method.java:511)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
  12-04 18:43:41.507: E/AndroidRuntime(30504):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>