title: Android: not able to trace down a ClassCastException with SimpleExpandableListAdapter
body: <p>I get the following exception running my program:</p>
  
  <pre><code>05-12 08:29:06.907: ERROR/AndroidRuntime(460): FATAL EXCEPTION: main
  05-12 08:29:06.907: ERROR/AndroidRuntime(460): java.lang.ClassCastException: java.util.ArrayList
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.SimpleExpandableListAdapter.getGroupView(SimpleExpandableListAdapter.java:278)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:445)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.AbsListView.obtainView(AbsListView.java:1294)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.ListView.measureHeightOfChildren(ListView.java:1198)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.ListView.onMeasure(ListView.java:1109)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:578)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:362)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:526)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.View.measure(View.java:8171)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.os.Handler.dispatchMessage(Handler.java:99)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.os.Looper.loop(Looper.java:123)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at android.app.ActivityThread.main(ActivityThread.java:4627)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at java.lang.reflect.Method.invokeNative(Native Method)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at java.lang.reflect.Method.invoke(Method.java:521)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  05-12 08:29:06.907: ERROR/AndroidRuntime(460):     at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>My own code nowhere shows up and I tried debugging, but the error occurs between my methods. I really don't know how to look for the reason!</p>
  
  <p>I am, in fact, changing the data behind the SimpleExpandableListAdapter, but what kind of error am I looking for here?</p>
  
  <p>Please, please help. :)</p>
  
  <p>Kind regards,
  jellyfish</p>