我在我的应用程序中使用可扩展列表，我的问题是当我在列表中向上和向下滚动，视图发生变化时，请告诉我如何解决此问题
谢谢， 萨姆。
下面是代码
package com.test.android;
import java.util.ArrayList;
import java.util.Random;
import android.app.ExpandableListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.Button;
import android.widget.ExpandableListAdapter;
import android.widget.TextView;
/**
* Demonstrates expandable lists using a custom {@link ExpandableListAdapter}
* from {@link BaseExpandableListAdapter}.
*/
public class ExpandableList1 extends ExpandableListActivity {
MyExpandableListAdapter mAdapter;
ProgressDialog progressDialog;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set up our adapter
mAdapter = new MyExpandableListAdapter(this);
setListAdapter(mAdapter);
}
/**
* A simple adapter which maintains an ArrayList of photo resource Ids.
* Each photo is displayed as an image. This adapter supports clearing the
* list of photos and adding a new photo.
*
*/
private Handler actionhandler = new Handler(){
/* (non-Javadoc)
* @see android.os.Handler#handleMessage(android.os.Message)
*/
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
mAdapter.notifyDataSetChanged();
progressDialog.dismiss();
}
};
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
private ArrayList<String> groups = new ArrayList<String>();
private ArrayList<ArrayList<String>> children = new ArrayList<ArrayList<String>>();
private Context context;
public MyExpandableListAdapter(Context context) {
super();
this.context = context;
groups.add("People Names");
groups.add("Dog Names");
groups.add("Cat Names");
groups.add("Fish Names");
ArrayList<String> child1 = new ArrayList<String>();
child1.add("Arnold-1");
child1.add("Barry-2");
child1.add("Chuck-3");
child1.add("David-4");
child1.add("Arnold-5");
child1.add("Barry-6");
child1.add("Chuck-7");
child1.add("David-8");
child1.add("Arnold-9");
child1.add("Barry-10");
child1.add("Chuck-11");
child1.add("David-12");
child1.add("Arnold-13");
child1.add("Barry-14");
child1.add("Chuck-15");
child1.add("David-16");
children.add(child1);
ArrayList<String> child2 = new ArrayList<String>();
child2.add("Ace-17");
child2.add("Bandit-18");
child2.add("Cha-Cha-19");
child2.add("Deuce-20");
children.add(child2);
ArrayList<String> child3 = new ArrayList<String>();
child3.add("Fluffy-21");
child3.add("Snuggles-22");
child3.add("Fluffy-23");
child3.add("Snuggles-24");
child3.add("Fluffy-25");
child3.add("Snuggles-26");
child3.add("Fluffy-27");
child3.add("Snuggles-28");
child3.add("Fluffy-29");
child3.add("Snuggles-30");
child3.add("Fluffy-31");
child3.add("Snuggles-32");
child3.add("Fluffy-33");
child3.add("Snuggles-34");
children.add(child3);
ArrayList<String> child4 = new ArrayList<String>();
child4.add("Goldy-35");
child4.add("Bubbles-36");
child4.add("dummy-37");
child4.add("Goldy-38");
child4.add("Bubbles-39");
child4.add("dummy-40");
child4.add("Goldy-41");
child4.add("Bubbles-42");
child4.add("dummy-43");
child4.add("Goldy-44");
child4.add("Bubbles-45");
child4.add("dummy-46");
child4.add("Goldy-47");
child4.add("Bubbles-48");
child4.add("dummy-49");
children.add(child4);
}
public Object getChild(int groupPosition, int childPosition) {
return children.get(groupPosition).get(childPosition);
}
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
public int getChildrenCount(int groupPosition) {
//if childern not avaibles.
return children.get(groupPosition).size();
}
private void getMoreData(int groupPosition, int childPosition){
Log.e("getMoreData", "calling groupPosition:"+groupPosition +"|childPosition:"+childPosition);
//remove the dummay record
children.get(groupPosition).remove(childPosition);
//adding a new group with data.
Random randomGenerator = new Random();
int count = randomGenerator.nextInt(100);
groups.add("More Data:" + count);
ArrayList<String> newData = new ArrayList<String>();
newData.add("Arnold"+count);
newData.add("Barry"+ count);
newData.add("Chuck"+ count);
newData.add("David"+ count);
children.add(newData);
//removing a record from exssitng group.
children.get(0).remove(0);
children.get(0).add("add to group0 shaggy");
//adding a record to group
children.get(1).add("shaggy add to group 2 shaggy");
//remove a groiup and corresponding childrens
groups.remove(2);
children.remove(2);
//adding a new record to last group.
children.get(groups.size()-1).add("new record");
//adding a dummy record to last group.
children.get(groups.size()-1).add("dummy");
}
public TextView getGenericView() {
// Layout parameters for the ExpandableListView
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT, 64);
TextView textView = new TextView(ExpandableList1.this);
textView.setLayoutParams(lp);
// Center the text vertically
textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
// Set the text starting position
textView.setPadding(36, 0, 0, 0);
return textView;
}
public Button getGenericButton(final int groupPosition,final int childPosition) {
// Layout parameters for the ExpandableListView
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT, 64);
Button button = new Button(ExpandableList1.this);
button.setText("More");
button.setLayoutParams(lp);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
progressDialog = ProgressDialog.show(context, null, "Please Wait");
new Thread(){
/* (non-Javadoc)
* @see java.lang.Thread#run()
*/
@Override
public void run() {
getMoreData(groupPosition,childPosition);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
actionhandler.sendEmptyMessage(0);
}
}.start();
}
});
// Center the text vertically
button.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
// Set the text starting position
button.setPadding(36, 0, 0, 0);
return button;
}
public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild,
View convertView, ViewGroup parent) {
Log.e("getChildView", groupPosition + "===" +groups.size());
if(convertView == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.chilldlayout_data, null);
// parent.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
}
if( groupPosition == groups.size()-1 && isLastChild){
//adding a button.
Button button = (Button)convertView.findViewById(R.id.more_button);
button.setVisibility(View.VISIBLE);
button.setText("More");
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
progressDialog = ProgressDialog.show(context, null, "Please Wait");
new Thread(){
/* (non-Javadoc)
* @see java.lang.Thread#run()
*/
@Override
public void run() {
getMoreData(groupPosition,childPosition);
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
actionhandler.sendEmptyMessage(0);
}
}.start();
}
});
// Center the text vertically
button.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
// Set the text starting position
button.setPadding(36, 0, 0, 0);
return convertView;
}else{
Button button = (Button)convertView.findViewById(R.id.more_button);
button.setVisibility(View.GONE);
TextView textView = (TextView)convertView.findViewById(R.id.textView_data);
textView.setText(getChild(groupPosition, childPosition).toString());
return convertView;
}
}
public Object getGroup(int groupPosition) {
return groups.get(groupPosition);
}
public int getGroupCount() {
return groups.size();
}
public long getGroupId(int groupPosition) {
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
ViewGroup parent) {
TextView textView = getGenericView();
textView.setText(getGroup(groupPosition).toString());
return textView;
}
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
public boolean hasStableIds() {
return true;
}
}
}