Question

I have started to work android application, I designed the layout in such RelativeLayout is the parent of the GridView, I simply want to set the LayoutParams of the GridView programmatically.

Below is my layout and code that How I am doing :

Layout.xml

<?xml version="1.0" encoding="utf-8"?>
    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="fill_parent" >

      <RelativeLayout
          xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/relativeLayout"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content" 
          android:background="#FFFFFF">

       <GridView
           xmlns:android="http://schemas.android.com/apk/res/android"
           android:id="@+id/gridview"
           android:layout_width="fill_parent"
           android:layout_height="510dp"
           android:gravity="center"
           android:horizontalSpacing="@dimen/image_grid_hspacing"
           android:numColumns="@integer/grid_num_cols"
           android:stretchMode="columnWidth"
           android:verticalSpacing="@dimen/image_grid_vspacing"
           android:background="#FFFFFF" />   

       </RelativeLayout>
    </ScrollView>

Code :

GridView gridview = (GridView) rootView.findViewById (R.id.gridview);
gridview.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, 300));

When I start my application then it always crashes and error logcat says

Error java.lang.ClassCastException: android.view.ViewGroup$LayoutParams

Sorry for a silly question, I don’t know the reason why it is throwing the exception. Please share your views on the question what could be possibilities for the exception

Answer 1

You are placing only LayoutParams which exists in all ViewGroup Objects. So need to mention clearly to which ViewGroup Object GridView belongs.

You change your code as below,

GridView gridview = (GridView) rootView.findViewById (R.id.gridview);
gridview.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, 300));