我正在尝试在可扩展列表视图中实现搜索过滤器。
但是当我尝试在editText中输入关键字时，应用程序会崩溃。
以下是MainActivity和ExpandableListAdapter的两个java类。
MainActivity类
package com.ahmedabadjobs.dashboard;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.EditText;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnGroupClickListener;
import androidhive.dashboard.R;
import com.ahmedabadjobs.expandablelistview.ExpandableListAdapter;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
EditText inputSearch;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get the listview
expListView = (ExpandableListView) findViewById(R.id.lvExp);
// preparing list data
prepareListData();
listAdapter = new ExpandableListAdapter(this, listDataHeader,
listDataChild);
// setting list adapter
expListView.setAdapter(listAdapter);
// Listview Group click listener
expListView.setOnGroupClickListener(new OnGroupClickListener() {
@Override
public boolean onGroupClick(ExpandableListView parent, View v,
int groupPosition, long id) {
// Toast.makeText(getApplicationContext(),
// "Group Clicked " + listDataHeader.get(groupPosition),
// Toast.LENGTH_SHORT).show();
return false;
}
});
inputSearch = (EditText) findViewById(R.id.inputSearch);
inputSearch.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence cs, int arg1, int arg2,
int arg3) {
// ((Filter) listAdapter.getFilter()).filter(cs);
NewsFeedActivity.this.listAdapter.getFilter().filter(cs);
}
@Override
public void beforeTextChanged(CharSequence arg0, int arg1,
int arg2, int arg3) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable arg0) {
// When user changed the Text
}
});
}
/*
* Preparing the list data
*/
private void prepareListData() {
listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();
// Adding child data
listDataHeader.add("Company 0");
listDataHeader.add("Company 1");
listDataHeader.add("Company 2");
// Adding child data
List<String> cignex = new ArrayList<String>();
company0.add("Address Line 1");
company0.add("Address Line 2");
company0.add("Address Line 3");
company0.add("Phone number");
company0.add("Email Address");
List<String> company1 = new ArrayList<String>();
company1.add("Address Line 1");
company1.add("Address Line 2");
company1.add("Address Line 3");
company1.add("Phone number");
company1.add("Email Address");
List<String> company2 = new ArrayList<String>();
company2.add("Address Line 1");
company2.add("Address Line 2");
company2.add("Address Line 3");
company2.add("Phone number");
company2.add("Email Address");
listDataChild.put(listDataHeader.get(0), company0); // Header, Child
// data
listDataChild.put(listDataHeader.get(1), company1);
listDataChild.put(listDataHeader.get(2), company2);
}
}
ExpandableListAdapter类
package com.ahmedabadjobs.expandablelistview;
import java.util.HashMap;
import java.util.List;
import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;
import androidhive.dashboard.R;
public class ExpandableListAdapter extends BaseExpandableListAdapter implements
Filterable {
private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;
public ExpandableListAdapter(Context context, List<String> listDataHeader,
HashMap<String, List<String>> listChildData) {
this._context = context;
this._listDataHeader = listDataHeader;
this._listDataChild = listChildData;
}
@Override
public Object getChild(int groupPosition, int childPosititon) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.get(childPosititon);
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public View getChildView(int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
final String childText = (String) getChild(groupPosition, childPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.list_item, null);
}
TextView txtListChild = (TextView) convertView
.findViewById(R.id.lblListItem);
txtListChild.setText(childText);
return convertView;
}
@Override
public int getChildrenCount(int groupPosition) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
}
@Override
public Object getGroup(int groupPosition) {
return this._listDataHeader.get(groupPosition);
}
@Override
public int getGroupCount() {
return this._listDataHeader.size();
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String headerTitle = (String) getGroup(groupPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.list_group, null);
}
TextView lblListHeader = (TextView) convertView
.findViewById(R.id.lblListHeader);
lblListHeader.setTypeface(null, Typeface.BOLD);
lblListHeader.setText(headerTitle);
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
@Override
public Filter getFilter() {
// TODO Auto-generated method stub
return null;
}
}
在editText中提供关键字时，我收到了以下错误。
12-09 03:37:48.080: E/InputEventSender(1139): Exception dispatching finished signal.
12-09 03:37:48.080: E/MessageQueue-JNI(1139): Exception in MessageQueue callback: handleReceiveCallback
12-09 03:37:48.161: E/MessageQueue-JNI(1139): java.lang.NullPointerException
请让我知道我需要做些什么改变才能使其正常运作。
答案 0 :(得分：0)
使用edittext如下
edit=(EditText)findViewById(R.id.editText1);
edit.addTextChangedListener(filterTextWatcher);
写一个textwatcher
private TextWatcher filterTextWatcher =new TextWatcher()
{
public void beforeTextChanged(CharSequence s, int start, int count,int after)
{
}
public void onTextChanged(CharSequence s, int start, int before,int count)
{
}
public void afterTextChanged(Editable s)
{
// TODO Auto-generated method stub
((Filterable) ((ListAdapter) Adapter)).getFilter().filter(edit.getText().toString());
}
};
按如下所示制作listadapter
public class ListAdapter extends BaseExpandableListAdapter implements Filterable {
public void notifyDataSetInvalidated()
{
super.notifyDataSetInvalidated();
}
public Filter getFilter()
{
if(filter == null)
filter = new MangaNameFilter();
return filter;
}
Filter类如下
private class MangaNameFilter extends Filter
{
@Override
protected FilterResults performFiltering(CharSequence constraint) {
// NOTE: this function is *always* called from a background thread, and
// not the UI thread.
constraint = edit.getText().toString().toLowerCase();
FilterResults result = new FilterResults();
if(constraint != null && constraint.toString().length() > 0)
{
detailsList=detailsSer.GetAlldetails();
dupCatList=detailsList;
ArrayList<detailsEntity> filt = new ArrayList<detailsEntity>();
ArrayList<detailsEntity> lItems = new ArrayList<detailsEntity>();
synchronized(this)
{
lItems.addAll(dupCatList);
}
for(int i = 0, l = lItems.size(); i < l; i++)
{
detailsEntity m = lItems.get(i);
if(m.description.toLowerCase().contains(constraint))
filt.add(m);
}
result.count = filt.size();
result.values = filt;
}
else
{
detailsList=detailsSer.GetAlldetails();
dupCatList=detailsList;
synchronized(this)
{
result.count = dupCatList.size();
result.values = dupCatList;
}
}
return result;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults result) {
// NOTE: this function is *always* called from the UI thread.
filtered = (ArrayList<detailsEntity>)result.values;
ArrayList<Integer> IdList = new ArrayList<Integer>();
IdList.clear();
for(int i=0;i<filtered.size();i++)
{
IdList.add(filtered.get(i).catID);
}
HashSet<Integer> hashSet = new HashSet<Integer>(IdList);
midList = new ArrayList<Integer>(hashSet) ;
Collections.sort(midList);
Adapter = new CategoryListAdapter(context, R.layout.list1, R.layout.list2, filtered, midList);
List.setAdapter(Adapter);
}
答案 1 :(得分：0)