我正在创建一个Android应用程序，它包含一个由数据库中的数据填充的列表视图。
这里我需要删除数据库中的数据以及列表视图并刷新列表视图。
我同时使用了notifyOnDataSetChanged()和notifyOnDataSetInvalidated()
它不适合我，请帮助我
package com.developer.milanandroid;
import android.app.ActionBar;
import android.app.Activity;
import android.database.Cursor;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.LinearLayout;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;
import com.gc.materialdesign.widgets.Dialog;
import com.milan.emptylayout.EmptyLayout;
import com.milan.lib.progressgenarator.lib.ProgressGenerator;
import com.milan.lib.progressgenarator.lib.ProgressGenerator.OnCompleteListener;
import com.milan.swipemenulistview.SwipeMenu;
import com.milan.swipemenulistview.SwipeMenuCreator;
import com.milan.swipemenulistview.SwipeMenuItem;
import com.milan.swipemenulistview.SwipeMenuListView;
import com.milan.swipemenulistview.SwipeMenuListView.OnMenuItemClickListener;
import com.processbutton.lib.milan.ActionProcessButton;
public class DatabaseListView extends Activity implements OnCompleteListener {
MediaPlayer media_player;
ActionProcessButton fetch_database;
SwipeMenuListView database_results;
LoginDataBaseAdapter logindatabase_adapter;
SimpleCursorAdapter cursoradapter;
Cursor cursor;
TextView username_txt,password_txt;
String user_name_string,password_string;
String text;
Dialog dialog;
private EmptyLayout empty_layout;
View.OnClickListener emptyClickListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.databaselistview);
View.OnClickListener mErrorClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
fetch_database.setText("Checking...");
empty_layout.showLoading();
ProgressGenerator pg = new ProgressGenerator(DatabaseListView.this);
pg.start(fetch_database);
}
};
emptyClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(DatabaseListView.this, "Try again button clicked", Toast.LENGTH_LONG).show();
}
};
ActionBar actionbar = getActionBar();
actionbar.hide();
View v;
LinearLayout linear = (LinearLayout)findViewById(R.id.linearLayout1);
username_txt = (TextView)linear.getChildAt(0);
password_txt = (TextView)linear.getChildAt(0);
user_name_string = username_txt.getText().toString();
password_string = password_txt.getText().toString();
fetch_database = (ActionProcessButton)findViewById(R.id.Button_Fetch_from_Database);
database_results = (SwipeMenuListView)findViewById(R.id.listview_database);
final ProgressGenerator progressGenerator = new ProgressGenerator(DatabaseListView.this);
logindatabase_adapter = new LoginDataBaseAdapter(DatabaseListView.this);
empty_layout = new EmptyLayout(DatabaseListView.this, database_results);
empty_layout.setErrorButtonClickListener(mErrorClickListener);
fetch_database.setMode(ActionProcessButton.Mode.PROGRESS);
fetch_database.setOnClickListener(new View.OnClickListener() {
@SuppressWarnings("deprecation")
@Override
public void onClick(View v) {
progressGenerator.start(fetch_database);
fetch_database.setText("Checking...");
fetch_database.setEnabled(false);
empty_layout.showLoading();
media_player = MediaPlayer.create(DatabaseListView.this, R.raw.retrievingfromdatabase);
media_player.start();
String[] from = {LoginDataBaseAdapter.USER_NAME,LoginDataBaseAdapter.USER_PASSWORD};
int[] to = {R.id.txt_username,R.id.txt_pasword};
cursor = logindatabase_adapter.feching_Data();
cursoradapter = new SimpleCursorAdapter(DatabaseListView.this, R.layout.listcell, cursor, from, to);
cursoradapter.notifyDataSetChanged();
//registerForContextMenu(database_results);
}
});
SwipeMenuCreator swipe_list_view = new SwipeMenuCreator() {
@Override
public void create(SwipeMenu menu) {
SwipeMenuItem open_swipemenu = new SwipeMenuItem(DatabaseListView.this);
open_swipemenu.setBackground(new ColorDrawable(Color.rgb(0x9B,0x33,0xF0)));
open_swipemenu.setWidth(dp2px(90));
open_swipemenu.setIcon(R.drawable.databasedelete);
menu.addMenuItem(open_swipemenu);
}
};
database_results.setMenuCreator(swipe_list_view);
database_results.setOnMenuItemClickListener(new OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(final int position, SwipeMenu menu, int index) {
switch(index) {
case 0:
dialog = new Dialog(DatabaseListView.this, "Delete Record", "Do you want to delete Record from database");
dialog.setCancelable(false);
dialog.setOnAcceptButtonClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
cursor = (Cursor) database_results.getItemAtPosition(position);
final int item_id = cursor.getInt(cursor.getColumnIndex(LoginDataBaseAdapter.ID));
cursor.getString(cursor.getColumnIndex(LoginDataBaseAdapter.USER_NAME));
cursor.getString(cursor.getColumnIndex(LoginDataBaseAdapter.USER_PASSWORD));
logindatabase_adapter.deleteEntry(item_id);
//database_results.removeViewAt(position);
//cursoradapter.notifyDataSetChanged();
database_results.invalidateViews();
}
});
dialog.show();
}
return false;
}
});
}
protected int dp2px(int dp) {
return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
getResources().getDisplayMetrics());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.database_list_view, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onComplete() {
if(cursor!=null && cursor.getCount()>0){
database_results.setAdapter(cursoradapter);
fetch_database.setEnabled(false);
fetch_database.setText("SUCCESS");
}
else{
/*fetch_database.setEnabled(false);
fetch_database.setText("OOPS");
fetch_database.setBackgroundColor(Color.parseColor("#ffb74d"));
final Dialog dialog_database = new Dialog(DatabaseListView.this, "Database Records", "No Records was found in the database");
dialog_database.setOnAcceptButtonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dialog_database.cancel();
}
});
dialog_database.show();*/
fetch_database.setText("OOPS");
fetch_database.setBackgroundColor(Color.parseColor("#ffb74d"));
empty_layout.showError();
}
}
}
这是我的LoginDatabase adpater：
package com.developer.milanandroid;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.view.View;
public class LoginDataBaseAdapter
{
//Database name
static final String DATABASE_NAME = "MilanloginRegistration.db";
static final int DATABASE_VERSION = 1;
public static final int NAME_COLUMN = 1;
// TODO: Create public field for each column in your table.
// SQL Statement to create a new database.
public static final String TABLE_NAME="MilanLoginregistration";
public static final String ID="_id";
public static final String USER_NAME="USERNAME";
public static final String USER_PASSWORD ="PASSWORD";
static final String DATABASE_CREATE = "create table "+ TABLE_NAME +
"( " +ID+" integer primary key autoincrement,"+"USERNAME text not null,"+USER_PASSWORD+" text not null); ";
// Variable to hold the database instance
public SQLiteDatabase db;
// Context of the application using the database.
private final Context context;
// Database open/upgrade helper
private DataBaseHelper dbHelper;
public LoginDataBaseAdapter(Context _context)
{
context = _context;
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public LoginDataBaseAdapter open() throws SQLException
{
db = dbHelper.getWritableDatabase();
return this;
}
public void close()
{
db.close();
}
public SQLiteDatabase getDatabaseInstance()
{
return db;
}
public LoginDataBaseAdapter opentoRead() throws android.database.SQLException{
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
db = dbHelper.getReadableDatabase();
return this;
}
public LoginDataBaseAdapter opentoWrite() throws android.database.SQLException{
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
db = dbHelper.getWritableDatabase();
return this;
}
public void Close(){
dbHelper.close();
}
public void insertEntry(String username,String password)
{
ContentValues newValues = new ContentValues();
newValues.put("USERNAME",username);
newValues.put("PASSWORD",password);
// Insert the row into your table
db.insert("MilanLoginregistration",null,newValues);
///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
}
public int deleteAll(){
return db.delete(TABLE_NAME, null, null);
}
public void deleteEntry(int id){
//String id=String.valueOf(ID);
db.delete(TABLE_NAME, ID+"="+id, null);
// Toast.makeText(context, "Number fo Entry Deleted Successfully : "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show();
}
public Cursor queue_all(){
String[] columns = new String[]{ID,"USERNAME","PASSWORD"};
Cursor cursor_queue_all =db.query(TABLE_NAME, columns, null, null, null, null, null);
return cursor_queue_all;
}
public Cursor feching_Data(){
String[] columns = {ID,USER_NAME,USER_PASSWORD};
db = dbHelper.getWritableDatabase();
Cursor cursor = db.query(TABLE_NAME, columns,null,null,null,null,null);
return cursor;
}
public String getSinlgeEntry(String userName)
{
Cursor cursor=db.query("MilanLoginregistration", null, " USERNAME=?", new String[]{userName}, null, null, null);
if(cursor.getCount()<1) // UserName Not Exist
{
cursor.close();
return "NOT EXIST";
}
cursor.moveToFirst();
String password= cursor.getString(cursor.getColumnIndex("PASSWORD"));
//cursor.close();
return password;
}
public String checkSinlgeEntry(String userName)
{
Cursor cursor=db.query("MilanLoginregistration", null, " USERNAME=?", new String[]{userName}, null, null, null);
if(cursor.getCount()>=1) // UserName Exist
{
cursor.close();
return "NOT EXIST";
}
// cursor.close();
return "";
}
public void updateEntry(String user_name,String pasword)
{
// Define the updated row content.
ContentValues updatedValues = new ContentValues();
// Assign values for each row.
updatedValues.put("USERNAME", user_name);
updatedValues.put("PASSWORD",pasword);
String where="USERNAME = ?";
db.update("MilanLoginregistration",updatedValues, where, new String[]{user_name});
}
/*public void Display(View v){
Cursor c = db.rawQuery("select * from MilanloginRegistration", null);
admin_settings_child.text_fetched_database_results.setText("");
c.moveToFirst();
do{
String username = c.getString(c.getColumnIndex("USERNAME"));
String password = c.getString(1);
admin_settings_child.text_fetched_database_results.append("USERNAME::-->"+username+"PASSWORD::-->"+password+"\n");
}while(c.moveToNext());
}*/
}
答案 0 :(得分：0)
请发布适配器的代码。在上面的代码中，您将从其他适配器中删除数据，并通知其他适配器更改的数据集。即在以下几行中，我看不到cursoradapter实际上正在更新的位置。
logindatabase_adapter.deleteEntry(item_id);
cursoradapter.notifyDataSetChanged();
cursoradapter.notifyDataSetInvalidated();
你也可以试试这个。
listview.getAdapter().notifyDataSetChanged();
为了正确实现数据交换功能，您需要另外创建自定义适配器，每次更改数据时只需设置列表适配器.i.e
listeview.setAdapter(modifiedAdapter);
listview.getAdapter.notifyDataSetChanged();
编辑1：
当您使用简单的游标适配器时，您需要在删除条目后添加以下行：
logindatabase_adapter.deleteEntry(item_id);
cursor = logindatabase_adapter.feching_Data();
//database_results.removeViewAt(position);
cursoradapter = new SimpleCursorAdapter(DatabaseListView.this, R.layout.listcell, cursor, from, to);
database_results.setAdapter(cursoradapter);
database_results.getAdapter().notifyDataSetChanged();
答案 1 :(得分：-1)
在适配器上使用notifyDataSetChanged()方法，如下所示：
final ArrayAdapter adapter = ((ArrayAdapter) getListAdapter());
runOnUiThread(new Runnable() {
public void run() {
adapter.notifyDataSetChanged();
}
});