我查看了大量信息，但未找到正确的解决方案。
我的代码：
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.safety.Whitelist;
import org.jsoup.select.Elements;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Typeface;
import android.os.AsyncTask;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.Button;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
public class ExpandableListAdapter extends BaseExpandableListAdapter {
MyPointsDB db;
ArrayList<String> arr_book_title = new ArrayList<String>();
ArrayList<String> arr_book_href = new ArrayList<String>();
String selGroupParam;
String selItemParam;
public static String PACKAGE_NAME;
File directory;
String directory_string;
private Context _context;
private List<String> _listDataHeader; // header titles
private List<String> _paramDataHeader;
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;
private List<String> _paramDataChild;
AlertDialog dialog;
public ExpandableListAdapter(Context context, List<String> listDataHeader, List<String> paramDataHeader, HashMap<String, List<String>> listChildData, List<String> paramChildData) {
this._context = context;
this._listDataHeader = listDataHeader;
this._paramDataHeader = paramDataHeader;
this._listDataChild = listChildData;
this._paramDataChild = paramChildData;
//PACKAGE_NAME = _context.getPackageName();
this.db = new MyPointsDB(_context);
}
@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;
}
public String getChildParam(int groupPosition, int childPosition) {
return _paramDataChild.get(childPosition).toString();
}
@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.setTag(_paramDataChild.get(childPosition).toString());
txtListChild.setText(childText);
Button btnItem = (Button) convertView.findViewById(R.id.iconShowParamItem);
btnItem.setTag(_paramDataChild.get(childPosition).toString());
btnItem.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
selItemParam = view.getTag().toString().trim();
final CharSequence[] items = {_context.getString(R.string.operation_del_book)};
AlertDialog.Builder builder = new AlertDialog.Builder(_context);
builder.setItems(items, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
String[] separated = selItemParam.split(";");
String url_base = separated[1];
// Delete book
if (items[item] == _context.getString(R.string.operation_del_book)) {
new AlertDialog.Builder(_context)
.setTitle(R.string.alert_del_book_caption)
.setMessage(R.string.alert_del_book_message)
.setPositiveButton(R.string.button_ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String[] separated = selItemParam.split(";");
String _id = separated[0];
db.deleteBOOKid(_id);
//Toast.makeText(_context, selItemParam, Toast.LENGTH_LONG).show();
//refreshList();
//Toast.makeText(_context, _context.getString(R.string.operation_del_book), Toast.LENGTH_SHORT).show();
}
})
.setNegativeButton(R.string.button_cancel,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
}).show();
}
}
});
AlertDialog alert = builder.create();
alert.show();
}
});
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);
Button btnGroup = (Button) convertView.findViewById(R.id.iconShowParamGroup);
btnGroup.setTag(_paramDataHeader.get(groupPosition).toString());
btnGroup.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
//Toast.makeText(_context, "btnGroup", Toast.LENGTH_SHORT).show();
selGroupParam = view.getTag().toString().trim();
final CharSequence[] items = {_context.getString(R.string.operation_add_book), _context.getString(R.string.operation_del_autor)};
AlertDialog.Builder builder = new AlertDialog.Builder(_context);
builder.setItems(items, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
//Toast.makeText(_context, items[item], Toast.LENGTH_SHORT).show();
String[] separated = selGroupParam.split(";");
String url_base = separated[1];
// Add book
if (items[item] == _context.getString(R.string.operation_add_book)) {
new selectBookInAutor().execute(url_base);
}
// Delete book
if (items[item] == _context.getString(R.string.operation_del_autor)) {
new AlertDialog.Builder(_context)
.setTitle(R.string.alert_del_autor_caption)
.setMessage(R.string.alert_del_autor_message)
.setPositiveButton(R.string.button_ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String[] separated = selGroupParam.split(";");
String _id = separated[0];
db.deleteAUTORid(_id);
notifyDataSetChanged();
}
})
.setNegativeButton(R.string.button_cancel,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
}).show();
}
}
});
AlertDialog alert = builder.create();
alert.show();
}
});
return convertView;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
private class selectBookInAutor extends AsyncTask<String, Void, String> {
ProgressDialog mProgressDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
arr_book_title.clear();
arr_book_href.clear();
mProgressDialog = new ProgressDialog(_context);
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
mProgressDialog.show();
}
@Override
protected String doInBackground(String... params) {
Document doc = null;
StringBuilder sb = new StringBuilder();
try {
doc = Jsoup.connect(params[0]).userAgent("Mozilla").get();
//Elements links = doc.select("dl>dl>dt>li>a");
Elements links = doc.select("li>a");
for (Element link : links) {
sb.append(link.text());
arr_book_title.add(link.text());
arr_book_href.add(Jsoup.clean(link.attr("abs:href"), Whitelist.basic()));
}
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
@Override
protected void onPostExecute(String result) {
if(!result.equals("")){
//Toast.makeText(_context, result, Toast.LENGTH_LONG).show();
final CharSequence[] items = arr_book_title.toArray(new CharSequence[arr_book_title.size()]);
final ArrayList seletedItems = new ArrayList();
AlertDialog.Builder builder = new AlertDialog.Builder(_context);
builder.setTitle("Select The Difficulty Level");
builder.setMultiChoiceItems(items, null, new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialog, int indexSelected, boolean isChecked) {
if (isChecked) {
seletedItems.add(indexSelected);
}else if(seletedItems.contains(indexSelected)){
seletedItems.remove(Integer.valueOf(indexSelected));
}
}
}).setPositiveButton(R.string.button_ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int id) {
//Toast.makeText(_context, seletedItems.toString(), Toast.LENGTH_SHORT).show();
for (Object s : seletedItems){
String[] separated = selGroupParam.split(";");
String _idautor = separated[0].toString();
long id_book = db.insertBOOK(_idautor, arr_book_href.get(Integer.valueOf(s.toString())).toString(), "", arr_book_title.get(Integer.valueOf(s.toString())).toString());
new saveBookInAutor().execute(arr_book_href.get(Integer.valueOf(s.toString())).toString(), _idautor, String.valueOf(id_book));
}
//refreshList();
}
}).setNegativeButton(R.string.button_cancel, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int id) {
}
}).create().show();
}else{
Toast.makeText(_context, "Error get book autor", Toast.LENGTH_SHORT).show();
}
mProgressDialog.dismiss();
}
}
private class saveBookInAutor extends AsyncTask<String, Void, String> {
ProgressDialog mProgressDialog2;
String _idautor = "", _idbook = "";
@Override
protected void onPreExecute() {
super.onPreExecute();
mProgressDialog2 = new ProgressDialog(_context);
mProgressDialog2.setMessage("Save page...");
mProgressDialog2.setIndeterminate(false);
mProgressDialog2.show();
}
@Override
protected String doInBackground(String... params) {
Document doc = null;
String _html = "";
_idautor = params[1];
_idbook = params[2];
try {
doc = Jsoup.connect(params[0]).userAgent("Mozilla").get();
_html = doc.select("dd").outerHtml();
} catch (IOException e) {
e.printStackTrace();
}
return Jsoup.clean(_html, Whitelist.basic());
}
@Override
protected void onPostExecute(String result) {
if(!result.equals("")){
Toast.makeText(_context, "Save file", Toast.LENGTH_SHORT).show();
String html = "<html lang='ru'><head><meta http-equiv='Content-Type' content='text/html; charset=UTF-8'/></head><body>"+result+"</body></html>";
//String html = result;
savePageToFile(_idautor + "_" + String.valueOf(_idbook), html);
}else{
Toast.makeText(_context, "Error save page", Toast.LENGTH_SHORT).show();
}
mProgressDialog2.dismiss();
}
}
public void refreshList() {
Intent intent = new Intent(_context, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
_context.startActivity(intent);
}
public void savePageToFile(String filename, String html) {
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(_context.openFileOutput(filename, Context.MODE_PRIVATE));
outputStreamWriter.write(html);
outputStreamWriter.close();
}
catch (IOException e) {
//Log.e("Exception", "File write failed: " + e.toString());
}
}
public String readPageFile(String filename) {
String ret = "";
try {
InputStream inputStream = _context.openFileInput(filename);
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String receiveString = "";
StringBuilder stringBuilder = new StringBuilder();
while ( (receiveString = bufferedReader.readLine()) != null ) {
stringBuilder.append(receiveString);
}
inputStream.close();
ret = stringBuilder.toString();
}
}
catch (FileNotFoundException e) {
//Log.e("login activity", "File not found: " + e.toString());
} catch (IOException e) {
//Log.e("login activity", "Can not read file: " + e.toString());
}
return ret;
}
}
问题是删除书籍。从数据库中删除书后，我想更新屏幕ExpandableListView。调用notifyDataSetChanged（）时会发生此错误。元素不会从屏幕上消失。
我找到了一个解决问题的拐杖：
Intent intent = new Intent(_context, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
_context.startActivity(intent);
但这并不完全正确。
我请求你的帮助。
答案 0 :(得分：0)
您从数据库中删除该项目，但它仍然存在于您拥有的列表中。删除项目后，您必须更新_listDataHeader列表，然后notifyDataSetChanged。您还应该删除与此项目对应的子项。由于您有许多列表，因此在删除项目时也会更新它们。
.setPositiveButton(R.string.button_ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String[] separated = selItemParam.split(";");
String _id = separated[0];
db.deleteBOOKid(_id);
//update lists here, and remove the header, child items and anything related..
// _listDataHeader.remove(groupPosition) // groupPosition should be final
// etc. etc.
notifyDataSetChanged();
} })
为确保数据一致，当您删除某些内容时...也删除其他相关项目..例如：
如果_paramDataChild和_paramDataHeader与要删除的项目相关，您可能也想要更新它们......以便它们没有与已删除项目相关的值。 （这取决于你的情况，我只是举个例子）