[英]Can't Edit or Update Room database entries
我正在構建一個應用程序,用戶可以在其中存儲他/她的用戶名和密碼。 該應用程序具有簡單的UI。 主線程在操作欄上具有條目列表,FAB和“全部刪除”圖標。 我的問題是我無法編輯和更新現有條目。
我的MainActivity.java
的onCreate()
中有以下代碼。 當用戶保留一個條目時,它將啟動AddEditEntry.java
活動。 這里發生的是,啟動的活動在其EditText
字段中沒有現有的條目數據:
adapter.setOnItemLongClickListener(new RecyclerViewAdapter.OnItemLongClickListener() {
@Override
public void onItemLongClick(Entries entries) {
Intent intent = new Intent(MainActivity.this, AddEditEntry.class);
intent.putExtra(AddEditEntry.EXTRA_USERNAME, entry.getUsername());
intent.putExtra(AddEditEntry.EXTRA_HINT, entry.getHint());
intent.putExtra(AddEditEntry.EXTRA_PASSWORD, entry.getPassword());
intent.putExtra(AddEditEntry.EXTRA_ID, entry.getId());
startActivityForResult(intent, EDIT_ENTRY_REQUEST);
}
});
在我的AddEditEntry.java
活動中,保存按鈕的onClick
中包含以下代碼。 我將新數據添加為意圖:
saveEntry.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent data = new Intent();
data.putExtra(EXTRA_USERNAME, usernameEditText.getText().toString());
data.putExtra(EXTRA_HINT, hintEditText.getText().toString());
data.putExtra(EXTRA_PASSWORD, passwordEditText.getText().toString());
int id = getIntent().getIntExtra(EXTRA_ID, -1);
if(id != -1){data.putExtra(EXTRA_ID, id);}
setResult(RESULT_OK, data);
finish();
}
});
然后回到我的MainActivity.jav
,這是我的onActivityResult()
:
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == ADD_ENTRY_REQUEST && resultCode == RESULT_OK){
String username = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_USERNAME);
String password = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_PASSWORD);
String hint = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_HINT);
Entries entry = new Entries(username, hint, password);
viewModel.insert(entry);
Toast.makeText(this, "Entry added!", Toast.LENGTH_SHORT).show();
}else if(requestCode == EDIT_ENTRY_REQUEST && resultCode == RESULT_OK){
int id = Objects.requireNonNull(data).getIntExtra(AddEditEntry.EXTRA_ID, -1);
String username = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_USERNAME);
String password = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_PASSWORD);
String hint = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_HINT);
if (id == -1){Toast.makeText(addEditEntry, "Something went wrong", Toast.LENGTH_SHORT).show();}
Entries entry = new Entries(username, hint, password);
entry.setId(id);
viewModel.update(entry);
Toast.makeText(this, "Entry updated", Toast.LENGTH_SHORT).show();
}
else{Toast.makeText(this, "Entry not added!", Toast.LENGTH_SHORT).show();}
}
當我運行應用程序並嘗試編輯條目時,Toast消息顯示為“條目已更新!”。 因此它可以運行該代碼,但更改不存在。 我嘗試停止應用程序並重新啟動以刷新它,但它仍然不存在。
ViewModel.java:
public class EntryViewModel extends AndroidViewModel {
private EntryRepository repository;
private LiveData<List<Entries>> allEntries;
public EntryViewModel(@NonNull Application application) {
super(application);
repository = new EntryRepository(application);
allEntries = repository.getAllEntries();
}
public void insert(Entries entries){repository.insert(entries);}
public void update(Entries entries){repository.update(entries);}
public void delete(Entries entries){repository.delete(entries);}
public void deleteAll(){repository.deleteAllEntries();}
public LiveData<List<Entries>> getAllEntries() {return allEntries;}
}
EntryRepository.java:
public class EntryRepository {
private EntryDAO entryDAO;
private LiveData<List<Entries>> allEntries;
public EntryRepository(Application application){
EntryDatabase database = EntryDatabase.getInstance(application);
entryDAO = database.generateDao();
allEntries = entryDAO.getAllEntries();
}
public void insert(Entries entries){new InsertEntryAsyncTask(entryDAO).execute(entries);}
public void update(Entries entries){new UpdateEntryAsyncTask(entryDAO).execute(entries);}
public void delete(Entries entries){new DeleteEntryAsyncTask(entryDAO).execute(entries);}
public void deleteAllEntries(){new DeleteAllEntriesAsyncTask(entryDAO).execute();}
public LiveData<List<Entries>> getAllEntries(){return allEntries;}
public static class InsertEntryAsyncTask extends AsyncTask<Entries, Void, Void>{
private EntryDAO entryDAO;
private InsertEntryAsyncTask(EntryDAO entryDAO){this.entryDAO = entryDAO;}
@Override
protected Void doInBackground(Entries... entries) {
entryDAO.insert(entries[0]);
return null;
}
}
public static class UpdateEntryAsyncTask extends AsyncTask<Entries, Void, Void>{
private EntryDAO entryDAO;
private UpdateEntryAsyncTask(EntryDAO entryDAO){
this.entryDAO = entryDAO;
}
@Override
protected Void doInBackground(Entries... entries) {
entryDAO.update(entries[0]);
return null;
}
}
public static class DeleteEntryAsyncTask extends AsyncTask<Entries, Void, Void>{
private EntryDAO entryDAO;
private DeleteEntryAsyncTask(EntryDAO entryDAO){this.entryDAO = entryDAO;}
@Override
protected Void doInBackground(Entries... entries) {
entryDAO.delete(entries[0]);
return null;
}
}
public static class DeleteAllEntriesAsyncTask extends AsyncTask<Void, Void, Void>{
private EntryDAO entryDAO;
private DeleteAllEntriesAsyncTask(EntryDAO entryDAO){this.entryDAO = entryDAO;}
@Override
protected Void doInBackground(Void... voids) {
entryDAO.deleteAllEntries();
return null;
}
}
}
EntryDAO.java:
@Dao
public interface EntryDAO {
@Insert
void insert(Entries entries);
@Update
void update(Entries entries);
@Delete
void delete(Entries entries);
@Query("DELETE FROM entries_table")
void deleteAllEntries();
@Query("SELECT * FROM entries_table")
LiveData<List<Entries>> getAllEntries();
}
Entries.java:
@Entity(tableName = "entries_table")
public class Entries {
@PrimaryKey(autoGenerate = true)
private int id;
private String username, hint, password;
public Entries(String username, String hint, String password){
this.username = username;
this.hint = hint;
this.password = password;
}
public Entries(){}
public int getId() {return id;}
public void setId(int id) {this.id = id;}
public String getUsername() {return username;}
public void setUsername(String username) {this.username = username;}
public String getHint() {return hint;}
public void setHint(String hint) {this.hint = hint;}
public String getPassword() {return password;}
public void setPassword(String password) {this.password = password;}
}
這是我的AddEditEntry.java
類的onCreate()
。 我添加了以下Toast消息,以查看它是否完全在接收數據,結果卻沒有。 Toast消息為空:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_addedit_entry);
usernameEditText = findViewById(R.id.username_field);
passwordEditText = findViewById(R.id.password_field);
hintEditText = findViewById(R.id.hint_field);
passwordABCD = findViewById(R.id.upp_checkbox);
passwordabcd = findViewById(R.id.low_checkbox);
password0123 = findViewById(R.id.num_checkbox);
passwordSymbols = findViewById(R.id.sym_checkbox);
radio4 = findViewById(R.id.four);
radio8 = findViewById(R.id.eight);
radio12 = findViewById(R.id.twelve);
radio16 = findViewById(R.id.sixteen);
Button generatePassword = findViewById(R.id.btn_password_generate);
Button saveEntry = findViewById(R.id.btn_save);
Intent intent = getIntent();
if(intent.hasExtra(EXTRA_ID)){
setTitle("Edit Entry");
usernameEditText.setText(Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_USERNAME));
passwordEditText.setText(Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_PASSWORD));
hintEditText.setText(Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_HINT));
Toast.makeText(this, "Info Received!!!", Toast.LENGTH_SHORT).show();
Toast.makeText(this, Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_USERNAME), Toast.LENGTH_SHORT).show();
Toast.makeText(this, Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_PASSWORD), Toast.LENGTH_SHORT).show();
Toast.makeText(this, Objects.requireNonNull(getIntent().getExtras()).getString(EXTRA_HINT), Toast.LENGTH_SHORT).show();
}
else{setTitle("Add Entry");}
generatePassword.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {passwordEditText.setText(generatedPassword());}});
saveEntry.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent data = new Intent();
data.putExtra(EXTRA_USERNAME, usernameEditText.getText().toString());
data.putExtra(EXTRA_HINT, hintEditText.getText().toString());
data.putExtra(EXTRA_PASSWORD, passwordEditText.getText().toString());
int id = getIntent().getIntExtra(EXTRA_ID, -1);
if(id != -1){data.putExtra(EXTRA_ID, id);}
setResult(RESULT_OK, data);
finish();
}
});
}
像這樣做
在您的MainActivity.java
....
....
adapter.setOnItemLongClickListener(new RecyclerViewAdapter.OnItemLongClickListener() {
@Override
public void onItemLongClick(Entries entries) {
entry = entries; // this is very important, entry holds the current edited item
Intent intent = new Intent(MainActivity.this, AddEditEntry.class);
intent.putExtra(AddEditEntry.EXTRA_USERNAME, entry.getUsername());
intent.putExtra(AddEditEntry.EXTRA_HINT, entry.getHint());
intent.putExtra(AddEditEntry.EXTRA_PASSWORD, entry.getPassword());
// no need to pass the id, it's a autogenerated field
// intent.putExtra(AddEditEntry.EXTRA_ID, entry.getId());
startActivityForResult(intent, EDIT_ENTRY_REQUEST);
}
});
....
...
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
if(requestCode == ADD_ENTRY_REQUEST && resultCode == RESULT_OK){
...
...
} else if(requestCode == EDIT_ENTRY_REQUEST && resultCode == RESULT_OK) {
// in an Edit operation, id should not be modified, so, no need to pass this parameter
// int id =
// Objects.requireNonNull(data).getIntExtra(AddEditEntry.EXTRA_ID, -1);
String username = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_USERNAME);
String password = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_PASSWORD);
String hint = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_HINT);
// entry already exists, so, no need to create a new one
//Entries entry = new Entries(username, hint, password);
//entry.setId(id);
entry.setUsername(username);
entry.setPassword(password);
entry.setHint(hint);
viewModel.update(entry);
Toast.makeText(this, "Entry updated", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Entry not added!", Toast.LENGTH_SHORT).show();
}
super.onActivityResult(requestCode, resultCode, data);
}
其他備注...
在您的RecyclerViewAdapter.java
// This is not needed. Your list is already created in your Room query
//private List<Entries> entries = new ArrayList<>();
private List<Entries> entries;
在您的MainActivity.java
// This is not needed
// AddEditEntry addEditEntry;
....
....
// addEditEntry = new AddEditEntry();
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