Question

I’m struggling with the ExpandableList View in Android.
I’m using the code provided in the apis demo but I don’t know how to solve my problem.

I got a white background on my view but when I’m scrolling the list it turns black..why?

I don’t want this effect…is there a way to change it? is there a way to customize the list using this code?
I’m looking for something like this..Hope you could help me!
Thank you 🙂

package com.example.android.apis.view;

import android.R;
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.widget.ExpandableListAdapter;
import android.widget.SimpleExpandableListAdapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


/**
 * Demonstrates expandable lists backed by a Simple Map-based adapter
 */
public class ExpandableList3 extends ExpandableListActivity {
    private static final String NAME = "NAME";
    private static final String IS_EVEN = "IS_EVEN";

    private ExpandableListAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        List<Map<String, String>> groupData = new ArrayList<Map<String, String>>();
        List<List<Map<String, String>>> childData = new ArrayList<List<Map<String, String>>>();
        for (int i = 0; i < 20; i++) {
            Map<String, String> curGroupMap = new HashMap<String, String>();
            groupData.add(curGroupMap);
            curGroupMap.put(NAME, "Group " + i);
            curGroupMap.put(IS_EVEN, (i % 2 == 0) ? "This group is even" : "This group is odd");

            List<Map<String, String>> children = new ArrayList<Map<String, String>>();
            for (int j = 0; j < 15; j++) {
                Map<String, String> curChildMap = new HashMap<String, String>();
                children.add(curChildMap);
                curChildMap.put(NAME, "Child " + j);
                curChildMap.put(IS_EVEN, (j % 2 == 0) ? "This child is even" : "This child is odd");
            }
            childData.add(children);
        }

        // Set up our adapter

        mAdapter = new SimpleExpandableListAdapter(
                this,
                groupData,
                android.R.layout.simple_expandable_list_item_1,
                new String[] { NAME, IS_EVEN },
                new int[] { android.R.id.text1, android.R.id.text2 },
                childData,
                R.layout.simple_expandable_list_item_3,
                new String[] { NAME, IS_EVEN },
                new int[] { android.R.id.text1, android.R.id.text2 }
                );

        setListAdapter(mAdapter);
    }

}

Answer 1

Add to your listview in the xml file:

android:cacheColorHint="#00000000"

or in your Java code:

getListView().setCacheColorHint(0);