I was also the victim of the same problem and tried your solution and now its working like a charm. Thanks buddy. :)
I just modified the code with String instead of custom domain model for the ease of other people.
MainActivity.java
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.Toast;
public class MainActivity extends Activity {
List<String> groupList;
List<String> childList;
Map<String, List<String>> laptopCollection;
ExpandableListView expListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d("-Test Exapansion-", "Nai Yara");
createGroupList();
createCollection();
expListView = (ExpandableListView) findViewById(R.id.laptop_list);
final MyExpandableListAdapter expListAdapter = new MyExpandableListAdapter
(getApplicationContext() ,
groupList, laptopCollection);
expListView.setAdapter(expListAdapter);
expListView.getHeaderViewsCount();
//expListView.expandGroup(1);
//expListView.expandGroup(2);
int numberOfHeaders = expListView.getExpandableListAdapter().getGroupCount();
Log.d("-Test Exapansion-", "Number of Groups are:"+numberOfHeaders);
for(int i = 0; i<numberOfHeaders; i++){
expListView.expandGroup(i);
}
setGroupIndicatorToRight();
expListView.setOnChildClickListener(new OnChildClickListener() {
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
final String selected = (String) expListAdapter.getChild(
groupPosition, childPosition);
Toast.makeText(getBaseContext(), selected, Toast.LENGTH_LONG)
.show();
return true;
}
});
}
private void createGroupList() {
groupList = new ArrayList<String>();
groupList.add("HP");
groupList.add("Dell");
groupList.add("Lenovo");
groupList.add("Sony");
groupList.add("HCL");
groupList.add("Samsung");
groupList.add("HTC");
}
private void createCollection() {
// preparing laptops collection(child)
String[] hpModels = { "HP Pavilion G6-2014TX", "ProBook HP 4540",
"HP Envy 4-1025TX" };
String[] hclModels = { "HCL S2101", "HCL L2102", "HCL V2002" };
String[] lenovoModels = { "IdeaPad Z Series", "Essential G Series",
"ThinkPad X Series", "Ideapad Z Series" };
String[] sonyModels = { "VAIO E Series", "VAIO Z Series",
"VAIO S Series", "VAIO YB Series" };
String[] dellModels = { "Inspiron", "Vostro", "XPS" };
String[] samsungModels = { "NP Series", "Series 5", "SF Series" };
String[] hTcModels = { "One", "One X", "Desire Series" };
laptopCollection = new LinkedHashMap<String, List<String>>();
for (String laptop : groupList) {
if (laptop.equals("HP")) {
loadChild(hpModels);
} else if (laptop.equals("Dell"))
loadChild(dellModels);
else if (laptop.equals("Sony"))
loadChild(sonyModels);
else if (laptop.equals("HCL"))
loadChild(hclModels);
else if (laptop.equals("Samsung"))
loadChild(samsungModels);
else if (laptop.equals("HTC"))
loadChild(hTcModels);
else
loadChild(lenovoModels);
laptopCollection.put(laptop, childList);
}
}
private void loadChild(String[] laptopModels) {
childList = new ArrayList<String>();
for (String model : laptopModels)
childList.add(model);
}
private void setGroupIndicatorToRight() {
/* Get the screen width */
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int width = dm.widthPixels;
expListView.setIndicatorBounds(width - getDipsFromPixel(35), width
- getDipsFromPixel(5));
}
// Convert pixel to dip
public int getDipsFromPixel(float pixels) {
// Get the screen's density scale
final float scale = getResources().getDisplayMetrics().density;
// Convert the dps to pixels, based on density scale
return (int) (pixels * scale + 0.5f);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
//getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
MyExpandableListAdapter.java
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.Toast;
public class MainActivity extends Activity {
List<String> groupList;
List<String> childList;
Map<String, List<String>> laptopCollection;
ExpandableListView expListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d("-Test Exapansion-", "Nai Yara");
createGroupList();
createCollection();
expListView = (ExpandableListView) findViewById(R.id.laptop_list);
final MyExpandableListAdapter
expListAdapter =
new MyExpandableListAdapter(getApplicationContext()
, groupList, laptopCollection);
expListView.setAdapter(expListAdapter);
expListView.getHeaderViewsCount();
int numberOfHeaders = expListView.getExpandableListAdapter().getGroupCount();
Log.d("-Test Exapansion-", "Number of Groups are:"+numberOfHeaders);
for(int i = 0; i<numberOfHeaders; i++){
expListView.expandGroup(i);
}
setGroupIndicatorToRight();
expListView.setOnChildClickListener(new OnChildClickListener() {
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
final String selected = (String) expListAdapter.getChild(
groupPosition, childPosition);
Toast.makeText(getBaseContext(), selected, Toast.LENGTH_LONG)
.show();
return true;
}
});
}
private void createGroupList() {
groupList = new ArrayList<String>();
groupList.add("HP");
groupList.add("Dell");
groupList.add("Lenovo");
groupList.add("Sony");
groupList.add("HCL");
groupList.add("Samsung");
groupList.add("HTC");
}
private void createCollection() {
// preparing laptops collection(child)
String[] hpModels = { "HP Pavilion G6-2014TX", "ProBook HP 4540",
"HP Envy 4-1025TX" };
String[] hclModels = { "HCL S2101", "HCL L2102", "HCL V2002" };
String[] lenovoModels = { "IdeaPad Z Series", "Essential G Series",
"ThinkPad X Series", "Ideapad Z Series" };
String[] sonyModels = { "VAIO E Series", "VAIO Z Series",
"VAIO S Series", "VAIO YB Series" };
String[] dellModels = { "Inspiron", "Vostro", "XPS" };
String[] samsungModels = { "NP Series", "Series 5", "SF Series" };
String[] hTcModels = { "One", "One X", "Desire Series" };
laptopCollection = new LinkedHashMap<String, List<String>>();
for (String laptop : groupList) {
if (laptop.equals("HP")) {
loadChild(hpModels);
} else if (laptop.equals("Dell"))
loadChild(dellModels);
else if (laptop.equals("Sony"))
loadChild(sonyModels);
else if (laptop.equals("HCL"))
loadChild(hclModels);
else if (laptop.equals("Samsung"))
loadChild(samsungModels);
else if (laptop.equals("HTC"))
loadChild(hTcModels);
else
loadChild(lenovoModels);
laptopCollection.put(laptop, childList);
}
}
private void loadChild(String[] laptopModels) {
childList = new ArrayList<String>();
for (String model : laptopModels)
childList.add(model);
}
private void setGroupIndicatorToRight() {
/* Get the screen width */
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int width = dm.widthPixels;
expListView.setIndicatorBounds(width - getDipsFromPixel(35), width
- getDipsFromPixel(5));
}
// Convert pixel to dip
public int getDipsFromPixel(float pixels) {
// Get the screen's density scale
final float scale = getResources().getDisplayMetrics().density;
// Convert the dps to pixels, based on density scale
return (int) (pixels * scale + 0.5f);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
//getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}