view - NullPointerException when using .addView to ViewGroup -

i'm trying use .addview add linearlayout viewgroup.

i getting following error on logcat:

05-21 16:23:04.096: e/androidruntime(2086): fatal exception: main 05-21 16:23:04.096: e/androidruntime(2086): java.lang.nullpointerexception 05-21 16:23:04.096: e/androidruntime(2086): @ android.view.viewgroup.addview(viewgroup.java:3148) 05-21 16:23:04.096: e/androidruntime(2086): @ android.view.viewgroup.addview(viewgroup.java:3131)

this code being called:

final linearlayout eventcontainersub =                         (linearlayout) findviewbyid(r.layout.event_container);                  final linearlayout eventcontainer =                         (linearlayout) findviewbyid(r.id.eventcontainer);                  eventcontainer.addview(eventcontainersub); 

here viewgroup (the first linear layout):

<linearlayout                 android:orientation="horizontal"                 android:layout_width="match_parent"                 android:layout_height="match_parent"                 android:animatelayoutchanges="true"                 android:id="@+id/eventcontainer"                 android:weightsum="100"                 android:duplicateparentstate="true"> 

and (second) linearlayout i'm adding (first one) linearlayout above:

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"               android:orientation="horizontal"               android:layout_width="match_parent"               android:layout_height="match_parent"               android:id="@+id/eventcontainersub"> 

both containers have exact same name..eventcontainersub.

there no eventcontainer, change view group container planned..

<linearlayout                 android:orientation="horizontal"                 android:layout_width="match_parent"                 android:layout_height="match_parent"                 android:animatelayoutchanges="true"                 android:id="@+id/event_container"                 android:weightsum="100"                 android:duplicateparentstate="true"> 

and make sure code asking right ids:

final linearlayout eventcontainersub = (linearlayout) findviewbyid(r.layout.eventcontainersub);

            final linearlayout eventcontainer =                     (linearlayout) findviewbyid(r.id.event_container); 

i'd suggest first remove subcontainer view if got inflated, view has parent , cannot attach subcontainer 2 parents.

either leave subcontainer file , create new one, or remove parent , add viewgroup want.

android layout replacing view view on run time

call removeview() on child's parent first