适配器上的 arraylist.remove() 删除了 ListView 中的错误项目
arraylist.remove() on adapter deletes wrong item in ListView
我有一个名为 AdapterActions 的 Adapter 扩展 ArrayAdapter<Action>。我给 AdapterActions 一个 ArrayList<Action>，它用那个 ArrayList 填充一个 ListView。问题是这样的：
假设这是我的 ArrayList：
ListaActions(0) = a
ListaActions(1) = b
ListaActions(2) = c
ListaActions(3) = d
ListaActions(4) = e
然后我执行 ListaActions.remove(2) 然后我清除每个 Action 对象并将其重新添加到 ListaActions，它成功地从 ArrayList 中删除了第三个对象，但在 ListView 中它删除最后一项（在本例中为 ListaActions(4) 的视图）并将该 ListView 上表示的已删除对象 (ListaActions(4)) 的每个 属性 设置为其默认值，即：int属性为 0，布尔属性为真...
当我关闭应用程序然后再次打开它时，它仍然是一样的，它不是 "refresh" ListView。有什么想法吗？
我读过一些关于 notifyDataSetChanged() 的帖子，但我认为如果它的作用是 "Notify that the Data Set changed"，它就无法工作，如果当我重新启动应用程序时它会重建所有内容和那些"empty" 视图仍然存在，ArrayList 上的最后一个对象未在列表视图中表示。
这是AdapterActions的代码：
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;
/*@SuppressLint("ViewHolder") */public class AdapterActions extends ArrayAdapter<Action>{
// our ViewHolder.
// caches our TextView
static class ViewHolderItem {
TextView codigo;
TextView accion;
TextView evento;
Switch UnSwitch;
boolean isChecked1;
}
Activity context;
ArrayList<Action> listaActions;
@SuppressLint("UseSparseArrays") Map <Integer, Boolean> map = new HashMap<Integer, Boolean>();
// Le pasamos al constructor el contexto y la lista de contactos
public AdapterActions(Activity context, ArrayList<Action> listaActions) {
super(context, R.layout.layout_adapter_actions, listaActions);
this.context = context;
this.listaActions = listaActions;
}
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolderItem viewHolder;
// Rescatamos cada item del listview y lo inflamos con nuestro layout
//View item = convertView;
//item = context.getLayoutInflater().inflate(R.layout.layout_adapter_actions, null);
// well set up the ViewHolder
viewHolder = new ViewHolderItem();
if(convertView==null){
// inflate the layout
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
convertView = inflater.inflate(R.layout.layout_adapter_actions, parent, false);
// well set up the ViewHolder
viewHolder.codigo = (TextView) convertView.findViewById(R.id.codigo);
viewHolder.accion = (TextView) convertView.findViewById(R.id.accion);
viewHolder.evento = (TextView) convertView.findViewById(R.id.evento);
viewHolder.UnSwitch = (Switch) convertView.findViewById(R.id.activa);
convertView.setLongClickable(true);
// store the holder with the view.
convertView.setTag(viewHolder);
}else{
// we've just avoided calling findViewById() on resource everytime
// just use the viewHolder
viewHolder = (ViewHolderItem) convertView.getTag();
}
Action a = new Action(0, 1, 1, true);
AccionDefinida LaAccion = new AccionDefinida(0, 0, "", "");
EventoDefinido ElEvento = new EventoDefinido(0, 0, "", "");
//ACTIONS
ActionsSQLite base = new ActionsSQLite(context, "Actions", null,1);
SQLiteDatabase db1 = base.getReadableDatabase();
db1 = context.openOrCreateDatabase("Actions",SQLiteDatabase.OPEN_READONLY, null);
String query = "SELECT * FROM Actions WHERE Id = " + String.valueOf(position + 1);
Cursor c1 = db1.rawQuery(query, null);
try{
if(c1!=null){
int i = c1.getColumnIndexOrThrow("Id");
int j = c1.getColumnIndexOrThrow("IdAccionDefinida");
int k = c1.getColumnIndexOrThrow("IdEventoDefinido");
int l = c1.getColumnIndexOrThrow("Activa");
boolean esActiva;
//Nos aseguramos de que existe al menos un registro
while(c1.moveToNext()){
if (c1.getInt(l) == 0){
esActiva = false;
} else
{
esActiva = true;
}
//Recorremos el cursor hasta que no haya más registros
a = new Action(c1.getInt(i), c1.getInt(j), c1.getInt(k), esActiva);
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdActions", "Error al abrir o crear la base de datos" + e);
}
if(db1!=null){
db1.close();
}
//EVENTOS
EventosDefinidosSQLite base2 = new EventosDefinidosSQLite(this.context, "EventosDefinidos", null, 1);
SQLiteDatabase db2 = base2.getReadableDatabase();
db2 = context.openOrCreateDatabase("EventosDefinidos",SQLiteDatabase.OPEN_READONLY, null);
String query2 = "SELECT * FROM EventosDefinidos WHERE Id = " + a.getIdEventoDefinido();
Cursor c2 = db2.rawQuery(query2, null);
try{
if(c2!=null){
int h = c2.getColumnIndexOrThrow("Id");
int k = c2.getColumnIndexOrThrow("IdEvento");
int i = c2.getColumnIndexOrThrow("Nombre");
int j = c2.getColumnIndexOrThrow("Aux");
//Nos aseguramos de que existe al menos un registro
while(c2.moveToNext()){
//Recorremos el cursor hasta que no haya más registros
ElEvento = new EventoDefinido(c2.getInt(h), c2.getInt(k), c2.getString(i), c2.getString(j));
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdEventos", "Error al abrir o crear la base de datos" + e);
}
if(db2!=null){
db2.close();
}
//ACCIONES
AccionesDefinidasSQLite base3 = new AccionesDefinidasSQLite(context, "AccionesDefinidas", null,1);
SQLiteDatabase db3 = base3.getReadableDatabase();
db3 = context.openOrCreateDatabase("AccionesDefinidas", SQLiteDatabase.OPEN_READONLY, null);
String query3 = "SELECT * FROM AccionesDefinidas WHERE Id = " + String.valueOf(a.getIdAccionDefinida());
Cursor c3 = db3.rawQuery(query3, null);
try{
if(c3!=null){
int h = c3.getColumnIndexOrThrow("Id");
int k = c3.getColumnIndexOrThrow("IdAccion");
int i = c3.getColumnIndexOrThrow("Nombre");
int j = c3.getColumnIndexOrThrow("Aux");
//Nos aseguramos de que existe al menos un registro
while(c3.moveToNext()){
//Recorremos el cursor hasta que no haya más registros
LaAccion = new AccionDefinida(c3.getInt(h), c3.getInt(k), c3.getString(i), c3.getString(j));
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdAcciones", "Error al abrir o crear la base de datos" + e);
}
if(db3!=null){
db3.close();
}
// object item based on the position
// assign values if the object is not null
if(a != null) {
// get the TextView from the ViewHolder and then set the text (item name) and tag (item ID) values
viewHolder.codigo.setText(String.valueOf(a.getId()));
viewHolder.codigo.setTag(a.getId());
viewHolder.accion.setText(LaAccion.getNombre());
viewHolder.evento.setText(ElEvento.getNombre());
viewHolder.UnSwitch.setChecked(a.getActiva());
Log.e("Position+1: "+ String.valueOf(position+1), "Id: "+ String.valueOf(a.getId()));
}
viewHolder.isChecked1 = viewHolder.UnSwitch.isChecked();
map.put(position, viewHolder.isChecked1);
viewHolder.UnSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.e("OnClick", "Se clickeó");
listaActions.get(position).setActiva(map.get(position));
Log.e("Listener del switch", "Modificó la action en la lista de la ActividadPrincipal");
int isActiva;
if(map.get(position) == true)
{
isActiva = 0;
Log.e("Listener del switch", "isActiva = 1");
map.put(position, false);
} else
{
isActiva = 1;
Log.e("Listener del switch", "isActiva = 0");
map.put(position, true);
}
String query = "UPDATE Actions SET Activa = " + String.valueOf(isActiva) + " WHERE Id = " + String.valueOf(position+1);
Log.e("Consulta:", query);
Log.e("Listener del switch", "query creado");
Log.e("La position debería ser", String.valueOf(position+1));
Log.e("Y el valor del map.get(position) es", String.valueOf(map.get(position)));
ActionsSQLite helper1 = new ActionsSQLite(context, "Actions", null, 1);
Log.e("Listener del switch", "Creo el helper");
SQLiteDatabase db = helper1.getWritableDatabase();
Log.e("Listener del switch", "obtenida la base escribible");
db.execSQL(query);
Log.e("Listener del switch", "Query ejecutado");
}
});
return convertView;
}
当我从 ArrayList 中删除一个对象时，我是从这个对话框中进行的：
import java.util.ArrayList;
import android.app.Activity;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
public class DialogModificarAction extends DialogFragment
{
public interface DialogModificarActionListener {
}
private int getIndex(Spinner spinner, ArrayList<String> MiLista){
int index = 0;
for(int j = 0;j<=MiLista.size();j++){
if (spinner.getSelectedItem().equals(MiLista.get(j))){
index = j;
break;
}
}
return index;
}
private Button cancelButton;
private Button confirmButton;
private Button deleteButton;
private Spinner spinnerAccion;
private Spinner spinnerEvento;
private static Action ActionAModificar = null;
private ArrayList<EventoDefinido> ListaEventosDefinidos = new ArrayList<EventoDefinido>();
private ArrayList<AccionDefinida> ListaAccionesDefinidas = new ArrayList<AccionDefinida>();
private ArrayList<String> ListaNombresAccionesDefinidas = new ArrayList<String>();
private ArrayList<String> ListaNombresEventosDefinidos = new ArrayList<String>();
public DialogModificarAction()
{
// Empty constructor required for DialogFragment
}
@SuppressWarnings("unused")
private DialogModificarActionListener dialogListener;
//This is how you can supply your fragment with information
public static DialogModificarAction newInstance(ArrayList<Action> ListaActions, ArrayList<AccionDefinida> ListaAccionesDefinidas, ArrayList<EventoDefinido> ListaEventosDefinidos, Action ActionAModificar)
{
DialogModificarAction myDialog = new DialogModificarAction();
Bundle args = new Bundle();
args.putParcelableArrayList("ListaActions", ListaActions);
args.putParcelableArrayList("ListaAccionesDefinidas", ListaAccionesDefinidas);
args.putParcelableArrayList("ListaEventosDefinidos", ListaEventosDefinidos);
args.putParcelable("ActionAModificar", ActionAModificar);
myDialog.setArguments(args);
return myDialog;
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setStyle(STYLE_NO_TITLE, 0); // Le saca el título al DialogFragment
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.dialog_modif_baja_action, container);
//DECLARO LOS ELEMENTOS EN EL LAYOUT
ActionAModificar = getArguments().getParcelable("ActionAModificar");
ListaAccionesDefinidas = getArguments().getParcelableArrayList("ListaAccionesDefinidas");
ListaEventosDefinidos = getArguments().getParcelableArrayList("ListaEventosDefinidos");
spinnerAccion = (Spinner)view.findViewById(R.id.spinnerAccionDefinida);
spinnerEvento = (Spinner)view.findViewById(R.id.spinnerEventoDefinido);
AccionDefinida AccionTemporal;
for(int i = 0; i<= ListaAccionesDefinidas.size()-1;i++)
{
AccionTemporal = ListaAccionesDefinidas.get(i);
ListaNombresAccionesDefinidas.add(AccionTemporal.getNombre());
}
EventoDefinido EventoTemporal;
for(int i = 0; i<= ListaEventosDefinidos.size()-1;i++)
{
EventoTemporal = ListaEventosDefinidos.get(i);
ListaNombresEventosDefinidos.add(EventoTemporal.getNombre());
}
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this.getActivity(), android.R.layout.simple_spinner_item, ListaNombresAccionesDefinidas);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerAccion.setAdapter(dataAdapter);
spinnerAccion.setSelection(ActionAModificar.getIdAccionDefinida()-1);
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this.getActivity(), android.R.layout.simple_spinner_item, ListaNombresEventosDefinidos);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerEvento.setAdapter(dataAdapter2);
spinnerEvento.setSelection(ActionAModificar.getIdEventoDefinido()-1);
//Setup cancel button listener
cancelButton = (Button) view.findViewById(R.id.cancelButton);
cancelButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
//Cerrar diálogo y no hacer nada
getDialog().dismiss();
}
});
//Setup confirm button listener
confirmButton = (Button) view.findViewById(R.id.confirmButton);
confirmButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
//Obtengo los ids de la accion y el evento
int IdAccionDefinidaSeleccionada;
int IdEventoDefinidoSeleccionado;
IdAccionDefinidaSeleccionada = ListaAccionesDefinidas.get(getIndex(spinnerAccion, ListaNombresAccionesDefinidas)).getId();
IdEventoDefinidoSeleccionado = ListaEventosDefinidos.get(getIndex(spinnerEvento, ListaNombresEventosDefinidos)).getId();
ActionAModificar.setIdAccionDefinida(IdAccionDefinidaSeleccionada);
ActionAModificar.setIdEventoDefinido(IdEventoDefinidoSeleccionado);
ActividadPrincipal.listaActions.get(ActionAModificar.getId()).setIdAccionDefinida(IdAccionDefinidaSeleccionada);
ActividadPrincipal.listaActions.get(ActionAModificar.getId()).setIdEventoDefinido(IdEventoDefinidoSeleccionado);
//Agrego la Action a la base de datos
ActionsSQLite helper1 = new ActionsSQLite(getActivity(), "Actions", null, 1);
SQLiteDatabase db = helper1.getWritableDatabase();
String myQuery = "UPDATE Actions SET IdAccionDefinida = " + String.valueOf(IdAccionDefinidaSeleccionada) + ", IdEventoDefinido = " + String.valueOf(IdEventoDefinidoSeleccionado) + " WHERE Id = " + String.valueOf(ActionAModificar.getId());
db.execSQL(myQuery);
ActividadPrincipal parent = (ActividadPrincipal) getActivity();
parent.listView.invalidateViews();
//Cerrar diálogo
getDialog().dismiss();
}
});
deleteButton = (Button) view.findViewById(R.id.deleteButton);
deleteButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
String query = "DELETE FROM Actions WHERE Id = " + String.valueOf(ActionAModificar.getId());
ActionsSQLite helper1 = new ActionsSQLite(getActivity(), "Actions", null, 1);
SQLiteDatabase db = helper1.getWritableDatabase();
db.execSQL(query);
Log.e("Listener del switch", "Query ejecutado");
ActividadPrincipal.listaActions.remove(ActionAModificar.getId()-1);
ActividadPrincipal.adapterActions.notifyDataSetChanged();
//Cerrar diálogo
getDialog().dismiss();
}
});
return view;
}
@Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
if (activity instanceof DialogModificarActionListener)
{
dialogListener = (DialogModificarActionListener) activity;
}
else
{
throw new ClassCastException(activity.toString() + " must implement dialogListener.DialogActionsListener");
}
}
@Override
public void onDismiss(DialogInterface dialog) {
ActividadPrincipal parent = (ActividadPrincipal) getActivity();
parent.ActualizarActions();
}
}
如果更改列表中的数据，则必须调用适配器的 notifyDataSetChanged 方法才能正常运行。
除此之外您可能还有其他错误，但 notifyDataSetChanged 绝对是必需的。先补充一下，如果还有问题再继续排查。
编辑：既然您已经展示了您的代码，我对它不起作用并不感到惊讶。您显然混淆了几个应该是独立实体的概念。特别是，您不应该从适配器访问数据库。
我不愿意花时间去尝试完全理解你的代码，坦率地说，它是一团糟，所以让我描述一下 应该走近了。
有两种基本情况。在第一个场景中，您有一个对象列表，并希望在 ListView 中显示它们。在第二种情况下，您在数据库中有对象，并希望在 ListView 中显示它们。这两种情况可能不应该混合。
在第一个（更简单的）场景中，您只需构造一个 ListAdapter，并将列表提供给适配器。在这种情况下，如果您从列表中删除一个项目，您还必须调用 ListAdapter 的 notifyDataSetChanged() 方法。如果您希望此删除在应用程序的当前 运行 之后持续存在，您可以自行更新列表的原始来源。
在第二种情况下，您将从数据库中获取 Cursor，可能使用从 ContentProvider 获取的 CursorLoader。然后，您将创建一个 CursorAdapter，并将其与 ListView 一起使用。在这种情况下，您要求 ContentProvider 从数据库中删除项目，这将自动导致 ContentProvider 更新 Cursor，并通知您 activity。然后，您将新光标提供给 CursorAdapter，并调用它的 notifyDataSetChanged 方法。
网络上有很多关于如何执行此操作的教程 - 我建议您阅读并查看一些示例。
我有一个名为 AdapterActions 的 Adapter 扩展 ArrayAdapter<Action>。我给 AdapterActions 一个 ArrayList<Action>，它用那个 ArrayList 填充一个 ListView。问题是这样的：
假设这是我的 ArrayList：
ListaActions(0) = a
ListaActions(1) = b
ListaActions(2) = c
ListaActions(3) = d
ListaActions(4) = e
然后我执行 ListaActions.remove(2) 然后我清除每个 Action 对象并将其重新添加到 ListaActions，它成功地从 ArrayList 中删除了第三个对象，但在 ListView 中它删除最后一项（在本例中为 ListaActions(4) 的视图）并将该 ListView 上表示的已删除对象 (ListaActions(4)) 的每个 属性 设置为其默认值，即：int属性为 0，布尔属性为真...
当我关闭应用程序然后再次打开它时，它仍然是一样的，它不是 "refresh" ListView。有什么想法吗？
我读过一些关于 notifyDataSetChanged() 的帖子，但我认为如果它的作用是 "Notify that the Data Set changed"，它就无法工作，如果当我重新启动应用程序时它会重建所有内容和那些"empty" 视图仍然存在，ArrayList 上的最后一个对象未在列表视图中表示。
这是AdapterActions的代码：
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;
/*@SuppressLint("ViewHolder") */public class AdapterActions extends ArrayAdapter<Action>{
// our ViewHolder.
// caches our TextView
static class ViewHolderItem {
TextView codigo;
TextView accion;
TextView evento;
Switch UnSwitch;
boolean isChecked1;
}
Activity context;
ArrayList<Action> listaActions;
@SuppressLint("UseSparseArrays") Map <Integer, Boolean> map = new HashMap<Integer, Boolean>();
// Le pasamos al constructor el contexto y la lista de contactos
public AdapterActions(Activity context, ArrayList<Action> listaActions) {
super(context, R.layout.layout_adapter_actions, listaActions);
this.context = context;
this.listaActions = listaActions;
}
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolderItem viewHolder;
// Rescatamos cada item del listview y lo inflamos con nuestro layout
//View item = convertView;
//item = context.getLayoutInflater().inflate(R.layout.layout_adapter_actions, null);
// well set up the ViewHolder
viewHolder = new ViewHolderItem();
if(convertView==null){
// inflate the layout
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
convertView = inflater.inflate(R.layout.layout_adapter_actions, parent, false);
// well set up the ViewHolder
viewHolder.codigo = (TextView) convertView.findViewById(R.id.codigo);
viewHolder.accion = (TextView) convertView.findViewById(R.id.accion);
viewHolder.evento = (TextView) convertView.findViewById(R.id.evento);
viewHolder.UnSwitch = (Switch) convertView.findViewById(R.id.activa);
convertView.setLongClickable(true);
// store the holder with the view.
convertView.setTag(viewHolder);
}else{
// we've just avoided calling findViewById() on resource everytime
// just use the viewHolder
viewHolder = (ViewHolderItem) convertView.getTag();
}
Action a = new Action(0, 1, 1, true);
AccionDefinida LaAccion = new AccionDefinida(0, 0, "", "");
EventoDefinido ElEvento = new EventoDefinido(0, 0, "", "");
//ACTIONS
ActionsSQLite base = new ActionsSQLite(context, "Actions", null,1);
SQLiteDatabase db1 = base.getReadableDatabase();
db1 = context.openOrCreateDatabase("Actions",SQLiteDatabase.OPEN_READONLY, null);
String query = "SELECT * FROM Actions WHERE Id = " + String.valueOf(position + 1);
Cursor c1 = db1.rawQuery(query, null);
try{
if(c1!=null){
int i = c1.getColumnIndexOrThrow("Id");
int j = c1.getColumnIndexOrThrow("IdAccionDefinida");
int k = c1.getColumnIndexOrThrow("IdEventoDefinido");
int l = c1.getColumnIndexOrThrow("Activa");
boolean esActiva;
//Nos aseguramos de que existe al menos un registro
while(c1.moveToNext()){
if (c1.getInt(l) == 0){
esActiva = false;
} else
{
esActiva = true;
}
//Recorremos el cursor hasta que no haya más registros
a = new Action(c1.getInt(i), c1.getInt(j), c1.getInt(k), esActiva);
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdActions", "Error al abrir o crear la base de datos" + e);
}
if(db1!=null){
db1.close();
}
//EVENTOS
EventosDefinidosSQLite base2 = new EventosDefinidosSQLite(this.context, "EventosDefinidos", null, 1);
SQLiteDatabase db2 = base2.getReadableDatabase();
db2 = context.openOrCreateDatabase("EventosDefinidos",SQLiteDatabase.OPEN_READONLY, null);
String query2 = "SELECT * FROM EventosDefinidos WHERE Id = " + a.getIdEventoDefinido();
Cursor c2 = db2.rawQuery(query2, null);
try{
if(c2!=null){
int h = c2.getColumnIndexOrThrow("Id");
int k = c2.getColumnIndexOrThrow("IdEvento");
int i = c2.getColumnIndexOrThrow("Nombre");
int j = c2.getColumnIndexOrThrow("Aux");
//Nos aseguramos de que existe al menos un registro
while(c2.moveToNext()){
//Recorremos el cursor hasta que no haya más registros
ElEvento = new EventoDefinido(c2.getInt(h), c2.getInt(k), c2.getString(i), c2.getString(j));
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdEventos", "Error al abrir o crear la base de datos" + e);
}
if(db2!=null){
db2.close();
}
//ACCIONES
AccionesDefinidasSQLite base3 = new AccionesDefinidasSQLite(context, "AccionesDefinidas", null,1);
SQLiteDatabase db3 = base3.getReadableDatabase();
db3 = context.openOrCreateDatabase("AccionesDefinidas", SQLiteDatabase.OPEN_READONLY, null);
String query3 = "SELECT * FROM AccionesDefinidas WHERE Id = " + String.valueOf(a.getIdAccionDefinida());
Cursor c3 = db3.rawQuery(query3, null);
try{
if(c3!=null){
int h = c3.getColumnIndexOrThrow("Id");
int k = c3.getColumnIndexOrThrow("IdAccion");
int i = c3.getColumnIndexOrThrow("Nombre");
int j = c3.getColumnIndexOrThrow("Aux");
//Nos aseguramos de que existe al menos un registro
while(c3.moveToNext()){
//Recorremos el cursor hasta que no haya más registros
LaAccion = new AccionDefinida(c3.getInt(h), c3.getInt(k), c3.getString(i), c3.getString(j));
}
}
else
Toast.makeText(context.getApplicationContext(),
"No hay nada :(", Toast.LENGTH_LONG).show();
}
catch (Exception e){
Log.i("bdAcciones", "Error al abrir o crear la base de datos" + e);
}
if(db3!=null){
db3.close();
}
// object item based on the position
// assign values if the object is not null
if(a != null) {
// get the TextView from the ViewHolder and then set the text (item name) and tag (item ID) values
viewHolder.codigo.setText(String.valueOf(a.getId()));
viewHolder.codigo.setTag(a.getId());
viewHolder.accion.setText(LaAccion.getNombre());
viewHolder.evento.setText(ElEvento.getNombre());
viewHolder.UnSwitch.setChecked(a.getActiva());
Log.e("Position+1: "+ String.valueOf(position+1), "Id: "+ String.valueOf(a.getId()));
}
viewHolder.isChecked1 = viewHolder.UnSwitch.isChecked();
map.put(position, viewHolder.isChecked1);
viewHolder.UnSwitch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.e("OnClick", "Se clickeó");
listaActions.get(position).setActiva(map.get(position));
Log.e("Listener del switch", "Modificó la action en la lista de la ActividadPrincipal");
int isActiva;
if(map.get(position) == true)
{
isActiva = 0;
Log.e("Listener del switch", "isActiva = 1");
map.put(position, false);
} else
{
isActiva = 1;
Log.e("Listener del switch", "isActiva = 0");
map.put(position, true);
}
String query = "UPDATE Actions SET Activa = " + String.valueOf(isActiva) + " WHERE Id = " + String.valueOf(position+1);
Log.e("Consulta:", query);
Log.e("Listener del switch", "query creado");
Log.e("La position debería ser", String.valueOf(position+1));
Log.e("Y el valor del map.get(position) es", String.valueOf(map.get(position)));
ActionsSQLite helper1 = new ActionsSQLite(context, "Actions", null, 1);
Log.e("Listener del switch", "Creo el helper");
SQLiteDatabase db = helper1.getWritableDatabase();
Log.e("Listener del switch", "obtenida la base escribible");
db.execSQL(query);
Log.e("Listener del switch", "Query ejecutado");
}
});
return convertView;
}
当我从 ArrayList 中删除一个对象时，我是从这个对话框中进行的：
import java.util.ArrayList;
import android.app.Activity;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
public class DialogModificarAction extends DialogFragment
{
public interface DialogModificarActionListener {
}
private int getIndex(Spinner spinner, ArrayList<String> MiLista){
int index = 0;
for(int j = 0;j<=MiLista.size();j++){
if (spinner.getSelectedItem().equals(MiLista.get(j))){
index = j;
break;
}
}
return index;
}
private Button cancelButton;
private Button confirmButton;
private Button deleteButton;
private Spinner spinnerAccion;
private Spinner spinnerEvento;
private static Action ActionAModificar = null;
private ArrayList<EventoDefinido> ListaEventosDefinidos = new ArrayList<EventoDefinido>();
private ArrayList<AccionDefinida> ListaAccionesDefinidas = new ArrayList<AccionDefinida>();
private ArrayList<String> ListaNombresAccionesDefinidas = new ArrayList<String>();
private ArrayList<String> ListaNombresEventosDefinidos = new ArrayList<String>();
public DialogModificarAction()
{
// Empty constructor required for DialogFragment
}
@SuppressWarnings("unused")
private DialogModificarActionListener dialogListener;
//This is how you can supply your fragment with information
public static DialogModificarAction newInstance(ArrayList<Action> ListaActions, ArrayList<AccionDefinida> ListaAccionesDefinidas, ArrayList<EventoDefinido> ListaEventosDefinidos, Action ActionAModificar)
{
DialogModificarAction myDialog = new DialogModificarAction();
Bundle args = new Bundle();
args.putParcelableArrayList("ListaActions", ListaActions);
args.putParcelableArrayList("ListaAccionesDefinidas", ListaAccionesDefinidas);
args.putParcelableArrayList("ListaEventosDefinidos", ListaEventosDefinidos);
args.putParcelable("ActionAModificar", ActionAModificar);
myDialog.setArguments(args);
return myDialog;
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setStyle(STYLE_NO_TITLE, 0); // Le saca el título al DialogFragment
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.dialog_modif_baja_action, container);
//DECLARO LOS ELEMENTOS EN EL LAYOUT
ActionAModificar = getArguments().getParcelable("ActionAModificar");
ListaAccionesDefinidas = getArguments().getParcelableArrayList("ListaAccionesDefinidas");
ListaEventosDefinidos = getArguments().getParcelableArrayList("ListaEventosDefinidos");
spinnerAccion = (Spinner)view.findViewById(R.id.spinnerAccionDefinida);
spinnerEvento = (Spinner)view.findViewById(R.id.spinnerEventoDefinido);
AccionDefinida AccionTemporal;
for(int i = 0; i<= ListaAccionesDefinidas.size()-1;i++)
{
AccionTemporal = ListaAccionesDefinidas.get(i);
ListaNombresAccionesDefinidas.add(AccionTemporal.getNombre());
}
EventoDefinido EventoTemporal;
for(int i = 0; i<= ListaEventosDefinidos.size()-1;i++)
{
EventoTemporal = ListaEventosDefinidos.get(i);
ListaNombresEventosDefinidos.add(EventoTemporal.getNombre());
}
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this.getActivity(), android.R.layout.simple_spinner_item, ListaNombresAccionesDefinidas);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerAccion.setAdapter(dataAdapter);
spinnerAccion.setSelection(ActionAModificar.getIdAccionDefinida()-1);
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this.getActivity(), android.R.layout.simple_spinner_item, ListaNombresEventosDefinidos);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerEvento.setAdapter(dataAdapter2);
spinnerEvento.setSelection(ActionAModificar.getIdEventoDefinido()-1);
//Setup cancel button listener
cancelButton = (Button) view.findViewById(R.id.cancelButton);
cancelButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
//Cerrar diálogo y no hacer nada
getDialog().dismiss();
}
});
//Setup confirm button listener
confirmButton = (Button) view.findViewById(R.id.confirmButton);
confirmButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
//Obtengo los ids de la accion y el evento
int IdAccionDefinidaSeleccionada;
int IdEventoDefinidoSeleccionado;
IdAccionDefinidaSeleccionada = ListaAccionesDefinidas.get(getIndex(spinnerAccion, ListaNombresAccionesDefinidas)).getId();
IdEventoDefinidoSeleccionado = ListaEventosDefinidos.get(getIndex(spinnerEvento, ListaNombresEventosDefinidos)).getId();
ActionAModificar.setIdAccionDefinida(IdAccionDefinidaSeleccionada);
ActionAModificar.setIdEventoDefinido(IdEventoDefinidoSeleccionado);
ActividadPrincipal.listaActions.get(ActionAModificar.getId()).setIdAccionDefinida(IdAccionDefinidaSeleccionada);
ActividadPrincipal.listaActions.get(ActionAModificar.getId()).setIdEventoDefinido(IdEventoDefinidoSeleccionado);
//Agrego la Action a la base de datos
ActionsSQLite helper1 = new ActionsSQLite(getActivity(), "Actions", null, 1);
SQLiteDatabase db = helper1.getWritableDatabase();
String myQuery = "UPDATE Actions SET IdAccionDefinida = " + String.valueOf(IdAccionDefinidaSeleccionada) + ", IdEventoDefinido = " + String.valueOf(IdEventoDefinidoSeleccionado) + " WHERE Id = " + String.valueOf(ActionAModificar.getId());
db.execSQL(myQuery);
ActividadPrincipal parent = (ActividadPrincipal) getActivity();
parent.listView.invalidateViews();
//Cerrar diálogo
getDialog().dismiss();
}
});
deleteButton = (Button) view.findViewById(R.id.deleteButton);
deleteButton.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
String query = "DELETE FROM Actions WHERE Id = " + String.valueOf(ActionAModificar.getId());
ActionsSQLite helper1 = new ActionsSQLite(getActivity(), "Actions", null, 1);
SQLiteDatabase db = helper1.getWritableDatabase();
db.execSQL(query);
Log.e("Listener del switch", "Query ejecutado");
ActividadPrincipal.listaActions.remove(ActionAModificar.getId()-1);
ActividadPrincipal.adapterActions.notifyDataSetChanged();
//Cerrar diálogo
getDialog().dismiss();
}
});
return view;
}
@Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
if (activity instanceof DialogModificarActionListener)
{
dialogListener = (DialogModificarActionListener) activity;
}
else
{
throw new ClassCastException(activity.toString() + " must implement dialogListener.DialogActionsListener");
}
}
@Override
public void onDismiss(DialogInterface dialog) {
ActividadPrincipal parent = (ActividadPrincipal) getActivity();
parent.ActualizarActions();
}
}
如果更改列表中的数据，则必须调用适配器的 notifyDataSetChanged 方法才能正常运行。
除此之外您可能还有其他错误，但 notifyDataSetChanged 绝对是必需的。先补充一下，如果还有问题再继续排查。
编辑：既然您已经展示了您的代码，我对它不起作用并不感到惊讶。您显然混淆了几个应该是独立实体的概念。特别是，您不应该从适配器访问数据库。
我不愿意花时间去尝试完全理解你的代码，坦率地说，它是一团糟，所以让我描述一下 应该走近了。
有两种基本情况。在第一个场景中，您有一个对象列表，并希望在 ListView 中显示它们。在第二种情况下，您在数据库中有对象，并希望在 ListView 中显示它们。这两种情况可能不应该混合。
在第一个（更简单的）场景中，您只需构造一个 ListAdapter，并将列表提供给适配器。在这种情况下，如果您从列表中删除一个项目，您还必须调用 ListAdapter 的 notifyDataSetChanged() 方法。如果您希望此删除在应用程序的当前 运行 之后持续存在，您可以自行更新列表的原始来源。
在第二种情况下，您将从数据库中获取 Cursor，可能使用从 ContentProvider 获取的 CursorLoader。然后，您将创建一个 CursorAdapter，并将其与 ListView 一起使用。在这种情况下，您要求 ContentProvider 从数据库中删除项目，这将自动导致 ContentProvider 更新 Cursor，并通知您 activity。然后，您将新光标提供给 CursorAdapter，并调用它的 notifyDataSetChanged 方法。
网络上有很多关于如何执行此操作的教程 - 我建议您阅读并查看一些示例。