实际上
我注意到我应该在 performFiltering 中使用“originalItems”列表来构建新的过滤列表。
这将解决您看到的有关更改过滤器中的文本的任何问题。例如，您搜索“Bread”，然后退格到“B”，您应该会看到所有“B”。在我原来的帖子中，你不会有。
private class GlycaemicIndexItemAdapter extends ArrayAdapter<GlycaemicIndexItem> {
private ArrayList<GlycaemicIndexItem> items;
private ArrayList<GlycaemicIndexItem> originalItems = new ArrayList<GlycaemicIndexItem>();
private GlycaemicIndexItemFilter filter;
private final Object mLock = new Object();
public GlycaemicIndexItemAdapter(Context context, int textViewResourceId, ArrayList<GlycaemicIndexItem> newItems) {
super(context, textViewResourceId, newItems);
this.items = newItems;
cloneItems(newItems);
}
protected void cloneItems(ArrayList<GlycaemicIndexItem> items) {
for (Iterator iterator = items.iterator(); iterator
.hasNext();) {
GlycaemicIndexItem gi = (GlycaemicIndexItem) iterator.next();
originalItems.add(gi);
}
}
@Override
public int getCount() {
synchronized(mLock) {
return items!=null ? items.size() : 0;
}
@Override
public GlycaemicIndexItem getItem(int item) {
GlycaemicIndexItem gi = null;
synchronized(mLock) {
gi = items!=null ? items.get(item) : null;
}
return gi;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row, null);
}
GlycaemicIndexItem i = null;
synchronized(mLock) {
i = items.get(position);
}
if (i != null) {
TextView tt = (TextView) v.findViewById(R.id.rowText);
TextView bt = (TextView) v.findViewById(R.id.rowText2);
if (tt != null) {
tt.setText("Name: "+i.getName());
}
if(bt != null){
bt.setText("GI Value: " + i.getGlycaemicIndex());
}
}
return v;
}
/**
* Implementing the Filterable interface.
*/
public Filter getFilter() {
if (filter == null) {
filter = new GlycaemicIndexItemFilter();
}
return filter;
}
/**
* Custom Filter implementation for the items adapter.
*
*/
private class GlycaemicIndexItemFilter extends Filter {
protected FilterResults performFiltering(CharSequence prefix) {
// Initiate our results object
FilterResults results = new FilterResults();
// No prefix is sent to filter by so we're going to send back the original array
if (prefix == null || prefix.length() == 0) {
synchronized (mLock) {
results.values = originalItems;
results.count = originalItems.size();
}
} else {
synchronized(mLock) {
// Compare lower case strings
String prefixString = prefix.toString().toLowerCase();
final ArrayList<GlycaemicIndexItem> filteredItems = new ArrayList<GlycaemicIndexItem>();
// Local to here so we're not changing actual array
final ArrayList<GlycaemicIndexItem> localItems = new ArrayList<GlycaemicIndexItem>();
localItems.addAll(originalItems);
final int count = localItems.size();
for (int i = 0; i < count; i++) {
final GlycaemicIndexItem item = localItems.get(i);
final String itemName = item.getName().toString().toLowerCase();
// First match against the whole, non-splitted value
if (itemName.startsWith(prefixString)) {
filteredItems.add(item);
} else {} /* This is option and taken from the source of ArrayAdapter
final String[] words = itemName.split(" ");
final int wordCount = words.length;
for (int k = 0; k < wordCount; k++) {
if (words[k].startsWith(prefixString)) {
newItems.add(item);
break;
}
}
} */
}
// Set and return
results.values = filteredItems;
results.count = filteredItems.size();
}//end synchronized
}
return results;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence prefix, FilterResults results) {
//noinspection unchecked
synchronized(mLock) {
final ArrayList<GlycaemicIndexItem> localItems = (ArrayList<GlycaemicIndexItem>) results.values;
notifyDataSetChanged();
clear();
//Add the items back in
for (Iterator iterator = localItems.iterator(); iterator
.hasNext();) {
GlycaemicIndexItem gi = (GlycaemicIndexItem) iterator.next();
add(gi);
}
}//end synchronized
}
}
}
基本上我正在构建一个健康和营养应用程序，一个屏幕将有一个基于血糖/血糖指数的项目列表。我希望用户能够键入并拥有屏幕自动过滤器。现在，如果您只使用字符串，您可以免费获得自动过滤。我不是，我有自己的自定义类 GlycaemicIndexItem，它有属性。我需要提供自己的过滤器，以确保在用户键入时更新用于在屏幕上绘制的列表。
当前屏幕是一个简单的 ListActivity，带有一个 ListView 和一个 EditText（用户输入）。我们将向此 EditText 附加一个 TextWatcher，以确保我们收到有关它的更新的通知。这意味着它应该适用于所有设备，无论用户在硬键盘还是软键盘上打字（我有一个 HTC DesireZ 和一个旧的 G1）。
这是屏幕/活动的布局 xml（有人可以告诉我如何将 xml 代码粘贴到此处，因为当我尝试使用代码块时，xml 没有正确粘贴/显示，而是被解释）：
由于我们想以自定义样式显示我们的行，我们还有一个用于行本身的布局 xml 文件：
这是整个 Activity 本身的代码。从ListActivity扩展，这个类有一个作为适配器的内部类，它从ArrayAdapter扩展而来。这是在 Activity 的 onCreate 中实例化的，并暂时传递了一个简单的字符串列表。注意它是如何在第 39-40 行创建的。我们对行的特殊布局与项目列表一起传入。
填充自定义行的关键在于适配器的方法getView。
我们的适配器类也有自己的内部类，称为 GlycaemicIndexItemFilter，它在用户键入时执行工作。我们的过滤器通过使用 TextWatcher 及其方法afterTextChanged绑定到第 43-44 行的 EditText 。第 47 行是我们如何实现过滤的线索。我们在过滤器对象上调用过滤器。我们的过滤器是在我们第一次调用 getFilter 时创建的，第 148-149 行。
package com.tilleytech.android.myhealthylife;
import java.util.ArrayList;
import java.util.Iterator;
import android.app.ListActivity;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Filter;
import android.widget.ListView;
import android.widget.TextView;
public class GlycaemicIndexAtoZActivity extends ListActivity {
/** Called when the activity is first created. */
private GlycaemicIndexItemAdapter giAdapter;
private TextWatcher filterTextWatcher;
private EditText filterText = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.giatoz);
ListView lv = getListView();
lv.setTextFilterEnabled(true);
// By using setAdapter method in listview we an add string array in list.
ArrayList<GlycaemicIndexItem> list = getListItems();
giAdapter = new GlycaemicIndexItemAdapter(this, R.layout.row, list);
giAdapter.notifyDataSetChanged();
setListAdapter(giAdapter);
filterText = (EditText)findViewById(R.id.GI_AtoZSearchEditText);
filterTextWatcher = new TextWatcher() {
public void afterTextChanged(Editable s) {
giAdapter.getFilter().filter(s); //Filter from my adapter
giAdapter.notifyDataSetChanged(); //Update my view
}
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
}
public void onTextChanged(CharSequence s, int start, int before,
int count) {
}
};
filterText.addTextChangedListener(filterTextWatcher);
}
private ArrayList<GlycaemicIndexItem> getListItems() {
ArrayList<GlycaemicIndexItem> result = new ArrayList<GlycaemicIndexItem>();
Resources res = getResources();
//Get our raw strings
String[] array = res.getStringArray(R.array.GIList);
for (int i = 0; i < array.length; i++) {
GlycaemicIndexItem gi = new GlycaemicIndexItem();
gi.setName(array[i]);
gi.setGlycaemicIndex(1);
result.add(gi);
}
return result;
}
private class GlycaemicIndexItemAdapter extends ArrayAdapter<GlycaemicIndexItem> {
private ArrayList<GlycaemicIndexItem> items;
private ArrayList<GlycaemicIndexItem> originalItems = new ArrayList<GlycaemicIndexItem>();
private GlycaemicIndexItemFilter filter;
private final Object mLock = new Object();
public GlycaemicIndexItemAdapter(Context context, int textViewResourceId, ArrayList<GlycaemicIndexItem> newItems) {
super(context, textViewResourceId, newItems);
this.items = newItems;
cloneItems(newItems);
}
protected void cloneItems(ArrayList<GlycaemicIndexItem> items) {
for (Iterator iterator = items.iterator(); iterator
.hasNext();) {
GlycaemicIndexItem gi = (GlycaemicIndexItem) iterator.next();
originalItems.add(gi);
}
}
@Override
public int getCount() {
synchronized(mLock) {
return items!=null ? items.size() : 0;
}
}
@Override
public GlycaemicIndexItem getItem(int item) {
GlycaemicIndexItem gi = null;
synchronized(mLock) {
gi = items!=null ? items.get(item) : null;
}
return gi;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row, null);
}
GlycaemicIndexItem i = null;
synchronized(mLock) {
i = items.get(position);
}
if (i != null) {
TextView tt = (TextView) v.findViewById(R.id.rowText);
TextView bt = (TextView) v.findViewById(R.id.rowText2);
if (tt != null) {
tt.setText("Name: "+i.getName());
}
if(bt != null){
bt.setText("GI Value: " + i.getGlycaemicIndex());
}
}
return v;
}
/**
* Implementing the Filterable interface.
*/
public Filter getFilter() {
if (filter == null) {
filter = new GlycaemicIndexItemFilter();
}
return filter;
}
/**
* Custom Filter implementation for the items adapter.
*
*/
private class GlycaemicIndexItemFilter extends Filter {
protected FilterResults performFiltering(CharSequence prefix) {
// Initiate our results object
FilterResults results = new FilterResults();
// No prefix is sent to filter by so we're going to send back the original array
if (prefix == null || prefix.length() == 0) {
synchronized (mLock) {
results.values = originalItems;
results.count = originalItems.size();
}
} else {
synchronized(mLock) {
// Compare lower case strings
String prefixString = prefix.toString().toLowerCase();
final ArrayList<GlycaemicIndexItem> filteredItems = new ArrayList<GlycaemicIndexItem>();
// Local to here so we're not changing actual array
final ArrayList<GlycaemicIndexItem> localItems = new ArrayList<GlycaemicIndexItem>();
localItems.addAll(originalItems);
final int count = localItems.size();
for (int i = 0; i < count; i++) {
final GlycaemicIndexItem item = localItems.get(i);
final String itemName = item.getName().toString().toLowerCase();
// First match against the whole, non-splitted value
if (itemName.startsWith(prefixString)) {
filteredItems.add(item);
} else {} /* This is option and taken from the source of ArrayAdapter
final String[] words = itemName.split(" ");
final int wordCount = words.length;
for (int k = 0; k < wordCount; k++) {
if (words[k].startsWith(prefixString)) {
newItems.add(item);
break;
}
}
} */
}
// Set and return
results.values = filteredItems;
results.count = filteredItems.size();
}//end synchronized
}
return results;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence prefix, FilterResults results) {
//noinspection unchecked
synchronized(mLock) {
final ArrayList<GlycaemicIndexItem> localItems = (ArrayList<GlycaemicIndexItem>) results.values;
notifyDataSetChanged();
clear();
//Add the items back in
for (Iterator iterator = localItems.iterator(); iterator
.hasNext();) {
GlycaemicIndexItem gi = (GlycaemicIndexItem) iterator.next();
add(gi);
}
}//end synchronized
}
}
}
}