我有一个带有 RecyclerView 的 Activity，它从我的 Fireabase 数据库获取对象列表。到目前为止，一切都按预期进行。 在适配器上，我有一个按钮可以删除一个对象。此按钮将从列表和数据库中删除对象。
当点击它时，该对象确实从两个地方都被删除了。它重复 RecyclerView 上的列表的问题。
如何解决此问题？
public class ApiariosListActivity extends AppCompatActivity implements ApiarioOnListAdapter.ApiarioClickListener {
private ApiarioOnListAdapter apiarioOnListAdapter;
private ArrayList<Apiario> apiList;
private static final int EDIT_APIARIO_REQUEST_CODE = 1;
private static final int ADD_APIARIO_REQUEST_CODE = 2;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_apiarios_list);
RecyclerView recyclerView = findViewById(R.id.recyclerViewApiarios);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
this.apiList = new ArrayList<>();
DatabaseReference mDatabaseQuery = FirebaseDatabase.getInstance().getReference("apiario");
Query query = mDatabaseQuery;
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for(DataSnapshot dataSnapshot : snapshot.getChildren()){
Apiario apiario = dataSnapshot.getValue(Apiario.class);
apiList.add(apiario);
}
apiarioOnListAdapter = new ApiarioOnListAdapter(apiList, ApiariosListActivity.this);
recyclerView.setAdapter(apiarioOnListAdapter);
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
// Add Apiario button
ImageButton btnAddApiario = findViewById(R.id.btnAddApiario);
btnAddApiario.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(ApiariosListActivity.this, SelectDistrictActivity.class);
startActivityForResult(intent, ADD_APIARIO_REQUEST_CODE);
}
});
}
@Override
protected void onRestart() {
super.onRestart();
Log.d("AnualDeclarationActivity", "JV: onRestart");
}
@Override
protected void onStart() {
super.onStart();
Log.d("AnualDeclarationActivity", "JV: onStart");
}
@Override
protected void onResume() {
super.onResume();
Log.d("AnualDeclarationActivity", "JV: onResume");
}
@Override
public void onEditClick(Apiario apiario) {
Log.d("AnualDeclarationActivity", "JV: onEditClick");
Intent intent = new Intent(this, EditApiarioActivity.class);
intent.putExtra("apiario", apiario);
startActivityForResult(intent, EDIT_APIARIO_REQUEST_CODE);
}
@Override
public void onDeleteClick(Apiario apiario) {
// Implement delete functionality, e.g., show a confirmation dialog
showDeleteConfirmationDialog(apiario);
}
private void showDeleteConfirmationDialog(final Apiario apiario) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Delete Apiario");
builder.setMessage("Are you sure you want to delete this Apiario?");
builder.setPositiveButton("Delete", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
// Perform the delete operation
deleteApiario(apiario);
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
// Cancel the delete operation
dialogInterface.dismiss();
}
});
builder.create().show();
}
private void deleteApiario(Apiario apiario) {
// Remove the apiario from the list
apiList.remove(apiario);
// Notify the adapter of the change
apiarioOnListAdapter.notifyDataSetChanged();
// Inform the user
Toast.makeText(this, "Apiario deleted: " + apiario.getNomeApiario(), Toast.LENGTH_SHORT).show();
}
private class PostDataTask extends AsyncTask<List<Apiario>, Void, String> {
@Override
protected void onPreExecute() {
Log.d("AsyncTask", "Executing onPreExecute");
}
@Override
protected String doInBackground(List<Apiario>... apiariosList) {
Log.d("AsyncTask", "Execute doInBackground");
// Create a JSON array to hold multiple Apiario objects
JSONArray apiarioArray = new JSONArray();
// Convert each Apiario object to a JSON object and add it to the array
for (Apiario apiario : apiariosList[0]) {
try {
JSONObject apiarioObject = new JSONObject();
apiarioObject.put("nomeApiario", apiario.getNomeApiario());
apiarioObject.put("apiarioDeTransumancia", apiario.isApiarioDeTransumancia()); // Example value, modify as needed
apiarioObject.put("numColmeias", apiario.getNumColmeias());
apiarioObject.put("numNucleos", apiario.getNumNucleos());
apiarioObject.put("coordenadaX", apiario.getCoordenadaX());
apiarioObject.put("coordenadaY", apiario.getCoordenadaY());
apiarioObject.put("freguesia", apiario.getFreguesia());
apiarioArray.put(apiarioObject);
} catch (JSONException e) {
e.printStackTrace();
}
}
// Create the main JSON object with the array
JSONObject mainJsonObject = new JSONObject();
try {
mainJsonObject.put("declarationModel", apiarioArray);
} catch (JSONException e) {
e.printStackTrace();
}
ApiCaller apiCaller = new ApiCaller();
String apiUrl = "http://10.0.2.2:5176/api/DeclarationController/SubmitAnualDeclaration";
String jsonInputString = mainJsonObject.toString();
Log.d("AsyncTask", "doInBackground: Making install request with JSON: " + jsonInputString);
String result = apiCaller.makePost(apiUrl, jsonInputString);
if (result != null) {
Log.d("AsyncTask", "doInBackground: Submission successful. Response: " + result);
return result;
} else {
Log.d("AsyncTask", "doInBackground: Submission request failed.");
return null;
}
}
@Override
protected void onPostExecute(String result) {
Log.d("AsyncTask", "FP : Executing onPostExecute");
if (result != null) {
Toast.makeText(ApiariosListActivity.this, "Success", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(ApiariosListActivity.this, "Error", Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
Log.d("TEST", "JV: onActivityResult - requestCode: " + requestCode + ", resultCode: " + resultCode);
Log.d("TEST", "JV: ON ACTIVITY");
if (requestCode == ADD_APIARIO_REQUEST_CODE && resultCode == RESULT_OK && data != null) {
// Retrieve the newly added Apiario object
Apiario newApiario = data.getParcelableExtra("newApiario");
// Add the new Apiario to the list
apiList.add(newApiario);
// Notify the adapter of the change
apiarioOnListAdapter.notifyDataSetChanged();
}
if (requestCode == EDIT_APIARIO_REQUEST_CODE && resultCode == RESULT_OK && data != null) {
Apiario modifiedApiario = data.getParcelableExtra("modifiedApiario");
int position = findPositionOfApiarioInList(modifiedApiario);
if (position != -1) {
apiList.set(position, modifiedApiario);
apiarioOnListAdapter.notifyItemChanged(position);
}
}
}
private int findPositionOfApiarioInList(Apiario apiario) {
for (int i = 0; i < apiList.size(); i++) {
if (apiList.get(i).getNomeApiario().equals(apiario.getNomeApiario())) {
return i;
}
}
return -1;
}
}
public class ApiarioOnListAdapter extends RecyclerView.Adapter<ApiarioOnListAdapter.ApiarioViewHolder> {
private List<Apiario> apiarios;
private ApiarioClickListener listener;
public interface ApiarioClickListener {
void onEditClick(Apiario apiario);
void onDeleteClick(Apiario apiario);
}
public ApiarioOnListAdapter(List<Apiario> apiarios, ApiarioClickListener listener) {
this.apiarios = apiarios;
this.listener = listener;
}
public class ApiarioViewHolder extends RecyclerView.ViewHolder {
TextView textName;
TextView textEstado;
Button btnEdit;
Button btnDelete;
LinearLayout buttonContainer; // Add this line
public ApiarioViewHolder(@NonNull View itemView) {
super(itemView);
textName = itemView.findViewById(R.id.textName);
textEstado = itemView.findViewById(R.id.textEstado);
btnEdit = itemView.findViewById(R.id.btnEdit);
btnDelete = itemView.findViewById(R.id.btnDelete);
buttonContainer = itemView.findViewById(R.id.buttonContainer);
}
}
@NonNull
@Override
public ApiarioViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.apiario_item_list, parent, false);
return new ApiarioViewHolder(itemView);
}
@Override
public void onBindViewHolder(@NonNull ApiarioViewHolder holder, int position) {
final Apiario apiario = apiarios.get(position);
holder.textName.setText("Nome: " + apiario.getNomeApiario());
holder.textEstado.setText("Estado: " + apiario.getEstado());
holder.btnEdit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Apiario selectedApiario = apiarios.get(holder.getAdapterPosition());
Log.d("TEST", "JV: SELECTED " + selectedApiario.getNomeApiario());
listener.onEditClick(selectedApiario);
}
});
holder.btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//listener.onDeleteClick(apiario);
int apiarioId = apiario.getID();
Log.d("TEST", "JV: ID A REMOVER " + apiarioId);
DatabaseReference apiarioRef = FirebaseDatabase.getInstance().getReference("apiario");
Query query = apiarioRef.orderByChild("id").equalTo(apiarioId);
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for (DataSnapshot data : snapshot.getChildren()) {
String apiarioId = data.getKey();
Log.d("TEST", "JV: ENTRA NO FOR DA REMOÇAO " + apiarioId);
// Obtém a referência do banco de dados para o nó 'apiario' usando o ID do apiário
DatabaseReference apiarioToRemoveRef = apiarioRef.child(apiarioId);
// Remove o nó 'apiario' da base de dados
apiarioToRemoveRef.removeValue();
// Opcional: Remover o APIário da lista local
apiarios.remove(apiario);
// Notificar o adapter sobre a mudança nos dados
notifyDataSetChanged();
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
});
// Check if the state is "Pendente" and add a button dynamically
if (apiario.getEstado().equalsIgnoreCase("Pendente")) {
Button customButton = new Button(holder.itemView.getContext());
customButton.setText("Confirmar");
// Add the button to the layout
holder.buttonContainer.addView(customButton);
// Set a click listener for the custom button
customButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Handle button click
// You can perform specific actions based on the button click
DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference("apiario");
Query query = mDatabase.orderByChild("id").equalTo(apiario.getID());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for (DataSnapshot data : snapshot.getChildren()){
String confirmID = data.getKey();
mDatabase.child(confirmID).child("estado").setValue("Aceite");
holder.buttonContainer.removeAllViews();
// Atualizar o estado na lista local
apiario.setEstado("Aceite");
// Notificar o adapter sobre a mudança nos dados
notifyDataSetChanged();
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
});
} else {
// If the state is not "Pendente", make sure to remove any previously added button
holder.buttonContainer.removeAllViews();
}
}
private void openEditApiarioActivity(Context context, Apiario apiario) {
Intent intent = new Intent(context, EditApiarioActivity.class);
intent.putExtra("apiario", apiario);
context.startActivity(intent);
}
@Override
public int getItemCount() {
return apiarios.size();
}
}
问题就在这里：
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_apiarios_list);
RecyclerView recyclerView = findViewById(R.id.recyclerViewApiarios);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
this.apiList = new ArrayList<>(); // 👈
DatabaseReference mDatabaseQuery = FirebaseDatabase.getInstance().getReference("apiario");
Query query = mDatabaseQuery;
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for(DataSnapshot dataSnapshot : snapshot.getChildren()){
Apiario apiario = dataSnapshot.getValue(Apiario.class);
apiList.add(apiario); // 👈
}
apiarioOnListAdapter = new ApiarioOnListAdapter(apiList, ApiariosListActivity.this);
recyclerView.setAdapter(apiarioOnListAdapter);
}
由于您使用
addValueEventListeneronDataChangequeryonCreateonDataChange更好的实现是：
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_apiarios_list);
RecyclerView recyclerView = findViewById(R.id.recyclerViewApiarios);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
this.apiList = new ArrayList<>();
DatabaseReference mDatabaseQuery = FirebaseDatabase.getInstance().getReference("apiario");
Query query = mDatabaseQuery;
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
apiList.clear(); // 👈 Clear previous results
for(DataSnapshot dataSnapshot : snapshot.getChildren()){
Apiario apiario = dataSnapshot.getValue(Apiario.class);
apiList.add(apiario);
}
apiarioOnListAdapter = new ApiarioOnListAdapter(apiList, ApiariosListActivity.this);
recyclerView.setAdapter(apiarioOnListAdapter);
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
throw error.toException(); // 👈 Never ignore errors
}
});