得到所有动态创建的linearlayout android java

Question

ScrollView sv = (ScrollView) v.findViewById(R.id.layout_question_content);
LinearLayout layout_questions = (LinearLayout) sv.findViewWithTag("layout_questions");
int childcount = layout_questions.getChildCount();
System.out.println("LinearLayout " + childcount);

I want to get All Linear Layout using tag but I get

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.widget.ScrollView.findViewWithTag(java.lang.Object)' on a null object reference

All my LinearLayout including all its child are dynamically added

XML

<ScrollView
        android:id="@+id/layout_question_content"
        android:clickable="true"
        android:layout_weight="1"
        android:layout_width="fill_parent"
        android:layout_marginBottom="50px"
        android:layout_height="fill_parent">

</ScrollView>

Answer 1

The ScrollView is either not defined in your XML or your <ScrollView /> does not have the id layout_question_content . Check that you have android:id="@+id/layout_question_content" set.