如何在房间数据库中使用多项选择
How to use Multiple Selection with Room Database
我怎样才能 link 交易到会员，就像 link 一个交易 ID 到多个会员 ID？
我有一个 activity 来创建新交易，在那个 activity 我输入交易的名称并有一个按钮可以插入。单击该按钮后，我想查看成员列表。
然后我要选择我要link的会员进行交易。通过单击每个成员，它应该会在我选择的成员旁边显示一个勾号或其他内容，或者它应该将单击的成员设置为不同的颜色。
那么交易应该与我选择的所有 linked 成员一起插入。
我现在是这样做的，我只是创建了一个新交易，点击它，用所选的交易开始一个新的 activity，然后在工具栏中我点击一个按钮开始另一个activity 我应该可以通过交易选择我想要 link 的成员。
是否可以在新交易activity中直接选择我要link的会员进行交易？或者是否可以进行新交易，当我单击按钮保存新交易时，它会将记录插入数据库并在插入后直接在 activity 中选择成员 link 到交易开始？
关于我的删除方法：我在 onSwipe 方法中实现了该方法。我怎样才能点击多个交易，它们有一个勾号或不同的颜色，然后同时删除它们？
我可以点击一个按钮（例如在工具栏中）删除，然后选择多个成员，点击一个"confirm delete"按钮，让确认屏幕出现（但还没有删除），然后接受确认屏幕，删除它们？
Class 交易：
@Entity(tableName = "transaction_table")
public class Transaction {
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "TransactionID")
private long id;
@ColumnInfo(name = "Transaction Name")
private String transactionName;
@ColumnInfo(name = "Transaction Balance")
private double balance;
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getTransactionName() {
return transactionName;
}
public void setTransactionName(String transactionName) {
this.transactionName = transactionName;
}
public Transaction(String transactionName, double balance) {
this.transactionName = transactionName;
this.balance = balance;
}
}
Class 会员:
@Entity(tableName = "member_table")
public class Member {
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "MemberID")
private long id;
@ColumnInfo(name = "First Name")
private String firstname;
@ColumnInfo(name = "Surname")
private String surname;
@ColumnInfo(name = "Balance")
private double balance;
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public Member(String firstname, String surname) {
this.firstname = firstname;
this.surname = surname;
this.balance = 0;
}
}
Class 交易主要 Activity:
public class TransactionMainActivity extends AppCompatActivity implements TransactionListAdapter.TransactionClickListener {
private TransactionViewModel mTransactionViewModel;
private List<Transaction> mTransaction;
public static final int NEW_TRANSACTION_ACTIVITY_REQUEST_CODE = 1;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.transaction_activity);
Toolbar toolbar = findViewById(R.id.toolbar_TransactionMainActivity);
setSupportActionBar(toolbar);
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle(R.string.Transaction);
}
FloatingActionButton fab = findViewById(R.id.fab_TransactionMainActivity);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(TransactionMainActivity.this, NewTransactionActivity.class);
startActivityForResult(intent, NEW_TRANSACTION_ACTIVITY_REQUEST_CODE);
}
});
RecyclerView recyclerView = findViewById(R.id.RecyclerViewCard_Transaction);
final TransactionListAdapter adapter = new TransactionListAdapter(this);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mTransactionViewModel = ViewModelProviders.of(this).get(TransactionViewModel.class);
mTransactionViewModel.getAllTransactions().observe(this, new Observer<List<Transaction>>() {
@Override
public void onChanged(@Nullable List<Transaction> transactions) {
mTransaction = transactions;
adapter.setTransaction(transactions);
}
});
ItemTouchHelper helper = new ItemTouchHelper(
new ItemTouchHelper.SimpleCallback(0,
ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder,
RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();
Transaction myTransaction = adapter.getTransactionAtPosition(position);
Toast.makeText(TransactionMainActivity.this,
getString(R.string.TransactionDeleted) + " " +
myTransaction.getTransactionName(), Toast.LENGTH_LONG).show();
mTransactionViewModel.delete(myTransaction);
}
});
helper.attachToRecyclerView(recyclerView);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.MainMenuToolbarSearch:
case R.id.MainMenuToolbarAdd:
case R.id.MainMenuToolbarDelete:
}
return super.onOptionsItemSelected(item);
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == NEW_TRANSACTION_ACTIVITY_REQUEST_CODE && resultCode == RESULT_OK) {
Transaction transaction = new Transaction(data.getStringExtra(NewTransactionActivity.EXTRA_REPLY), data.getDoubleExtra(NewTransactionActivity.EXTRA_REPLY2, -1));
mTransactionViewModel.insert(transaction);
} else
{
Toast.makeText(
getApplicationContext(),
R.string.transaction_not_saved,
Toast.LENGTH_LONG).show();
}
}
Class 新交易 Activity:
public class NewTransactionActivity extends AppCompatActivity {
public static final String EXTRA_REPLY = "com.example.android.transactionlistsql.REPLY";
public static final String EXTRA_REPLY2 = "com.example.android.transactionlistsql.REPLY2";
private EditText mEditTextTransaction;
private EditText mEditTextTransaction2;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.newtransaction_activity);
mEditTextTransaction = findViewById(R.id.NewTransactionName);
mEditTextTransaction2 = findViewById(R.id.NewTransactionBalance);
mEditTextTransaction2.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL);
mEditTextTransaction2.setText("0");
final Button button = findViewById(R.id.NewTransactionButtonSave);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent replyIntent = new Intent();
if (TextUtils.isEmpty(mEditTextTransaction.getText())){
Toast.makeText(getApplicationContext(), R.string.TransactionNameMissing, Toast.LENGTH_LONG).show();
return;
}
else if (TextUtils.isEmpty(mEditTextTransaction2.getText())){
mEditTextTransaction2.setText("0");
}
else {
String newtransactionname = mEditTextTransaction.getText().toString();
double newtransactionbalance = (Double.parseDouble(mEditTextTransaction2.getText().toString()));
replyIntent.putExtra(EXTRA_REPLY, newtransactionname);
replyIntent.putExtra(EXTRA_REPLY2, newtransactionbalance);
setResult(RESULT_OK, replyIntent);
}
finish();
}
});
}
}
我的 AsyncTask 插入方法：
private static class insertAsyncTask extends AsyncTask<Transaction, Void, Void> {
private TransactionDao mAsyncTaskDao;
insertAsyncTask(TransactionDao dao) {
mAsyncTaskDao = dao;
}
@Override
protected Void doInBackground(final Transaction... params) {
mAsyncTaskDao.insert(params[0]);
return null;
}
}
标记为错误的行是这一行：mAsyncTaskDao.insert(params[0]);
错误：
07-11 03:10:49.003 16307-16508/com.example.mainbuchhaltung E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #4
Process: com.example.mainbuchhaltung, PID: 16307
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.database.sqlite.SQLiteConstraintException: FOREIGN KEY constraint failed (code 787)
#################################################################
Error Code : 787 (SQLITE_CONSTRAINT_FOEIGNKEY)
Caused By : Abort due to constraint violation.
(FOREIGN KEY constraint failed (code 787))
#################################################################
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:915)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.arch.persistence.db.framework.FrameworkSQLiteStatement.executeInsert(FrameworkSQLiteStatement.java:50)
at android.arch.persistence.room.EntityInsertionAdapter.insert(EntityInsertionAdapter.java:64)
at com.example.mainbuchhaltung.Transaction.TransactionDao_Impl.insert(TransactionDao_Impl.java:96)
at com.example.mainbuchhaltung.Transaction.TransactionRepository$insertAsyncTask.doInBackground(TransactionRepository.java:64)
at com.example.mainbuchhaltung.Transaction.TransactionRepository$insertAsyncTask.doInBackground(TransactionRepository.java:54)
at android.os.AsyncTask.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
... 4 more
创建事务和成员实体之间的关系，如前所述
然后，一旦您获得交易数据（交易名称和金额），您就必须将数据传递给 MemberList activity，例如 here
现在，在您的会员列表屏幕中完成您的选择后，请遵循以下过程：
假设您在字符串中有成员 ID。
String memberIds = "12,18,25,27,30";
现在您必须创建所有成员 ID 分开的交易实体对象，并将其插入交易的 table 中，如下所示。
String[] memberArray = memberIds.split(",", memberIds.length());
for(String memberId : memberArray){
// transactionName & transactionAmount which you received in the bundle from add transaction activity
Transaction objTransaction = new Transaction(transactionName, transactionAmount);
objTransaction.setMemberId(Long.parseLong(memberId));
// Insert data into your database
mTransactionViewModel.insert(objTransaction);
}
它将为 "transaction_table" table 中的每个 memberId 创建一个单独的条目，具有一对一的关系。
您可以通过执行上述查询来获取交易数据
我怎样才能 link 交易到会员，就像 link 一个交易 ID 到多个会员 ID？
我有一个 activity 来创建新交易，在那个 activity 我输入交易的名称并有一个按钮可以插入。单击该按钮后，我想查看成员列表。
然后我要选择我要link的会员进行交易。通过单击每个成员，它应该会在我选择的成员旁边显示一个勾号或其他内容，或者它应该将单击的成员设置为不同的颜色。
那么交易应该与我选择的所有 linked 成员一起插入。
我现在是这样做的，我只是创建了一个新交易，点击它，用所选的交易开始一个新的 activity，然后在工具栏中我点击一个按钮开始另一个activity 我应该可以通过交易选择我想要 link 的成员。
是否可以在新交易activity中直接选择我要link的会员进行交易？或者是否可以进行新交易，当我单击按钮保存新交易时，它会将记录插入数据库并在插入后直接在 activity 中选择成员 link 到交易开始？
关于我的删除方法：我在 onSwipe 方法中实现了该方法。我怎样才能点击多个交易，它们有一个勾号或不同的颜色，然后同时删除它们？
我可以点击一个按钮（例如在工具栏中）删除，然后选择多个成员，点击一个"confirm delete"按钮，让确认屏幕出现（但还没有删除），然后接受确认屏幕，删除它们？
Class 交易：
@Entity(tableName = "transaction_table")
public class Transaction {
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "TransactionID")
private long id;
@ColumnInfo(name = "Transaction Name")
private String transactionName;
@ColumnInfo(name = "Transaction Balance")
private double balance;
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getTransactionName() {
return transactionName;
}
public void setTransactionName(String transactionName) {
this.transactionName = transactionName;
}
public Transaction(String transactionName, double balance) {
this.transactionName = transactionName;
this.balance = balance;
}
}
Class 会员:
@Entity(tableName = "member_table")
public class Member {
@PrimaryKey(autoGenerate = true)
@ColumnInfo(name = "MemberID")
private long id;
@ColumnInfo(name = "First Name")
private String firstname;
@ColumnInfo(name = "Surname")
private String surname;
@ColumnInfo(name = "Balance")
private double balance;
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
public String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public Member(String firstname, String surname) {
this.firstname = firstname;
this.surname = surname;
this.balance = 0;
}
}
Class 交易主要 Activity:
public class TransactionMainActivity extends AppCompatActivity implements TransactionListAdapter.TransactionClickListener {
private TransactionViewModel mTransactionViewModel;
private List<Transaction> mTransaction;
public static final int NEW_TRANSACTION_ACTIVITY_REQUEST_CODE = 1;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.transaction_activity);
Toolbar toolbar = findViewById(R.id.toolbar_TransactionMainActivity);
setSupportActionBar(toolbar);
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle(R.string.Transaction);
}
FloatingActionButton fab = findViewById(R.id.fab_TransactionMainActivity);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(TransactionMainActivity.this, NewTransactionActivity.class);
startActivityForResult(intent, NEW_TRANSACTION_ACTIVITY_REQUEST_CODE);
}
});
RecyclerView recyclerView = findViewById(R.id.RecyclerViewCard_Transaction);
final TransactionListAdapter adapter = new TransactionListAdapter(this);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
mTransactionViewModel = ViewModelProviders.of(this).get(TransactionViewModel.class);
mTransactionViewModel.getAllTransactions().observe(this, new Observer<List<Transaction>>() {
@Override
public void onChanged(@Nullable List<Transaction> transactions) {
mTransaction = transactions;
adapter.setTransaction(transactions);
}
});
ItemTouchHelper helper = new ItemTouchHelper(
new ItemTouchHelper.SimpleCallback(0,
ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
@Override
public boolean onMove(RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder,
RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();
Transaction myTransaction = adapter.getTransactionAtPosition(position);
Toast.makeText(TransactionMainActivity.this,
getString(R.string.TransactionDeleted) + " " +
myTransaction.getTransactionName(), Toast.LENGTH_LONG).show();
mTransactionViewModel.delete(myTransaction);
}
});
helper.attachToRecyclerView(recyclerView);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.MainMenuToolbarSearch:
case R.id.MainMenuToolbarAdd:
case R.id.MainMenuToolbarDelete:
}
return super.onOptionsItemSelected(item);
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == NEW_TRANSACTION_ACTIVITY_REQUEST_CODE && resultCode == RESULT_OK) {
Transaction transaction = new Transaction(data.getStringExtra(NewTransactionActivity.EXTRA_REPLY), data.getDoubleExtra(NewTransactionActivity.EXTRA_REPLY2, -1));
mTransactionViewModel.insert(transaction);
} else
{
Toast.makeText(
getApplicationContext(),
R.string.transaction_not_saved,
Toast.LENGTH_LONG).show();
}
}
Class 新交易 Activity:
public class NewTransactionActivity extends AppCompatActivity {
public static final String EXTRA_REPLY = "com.example.android.transactionlistsql.REPLY";
public static final String EXTRA_REPLY2 = "com.example.android.transactionlistsql.REPLY2";
private EditText mEditTextTransaction;
private EditText mEditTextTransaction2;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.newtransaction_activity);
mEditTextTransaction = findViewById(R.id.NewTransactionName);
mEditTextTransaction2 = findViewById(R.id.NewTransactionBalance);
mEditTextTransaction2.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL);
mEditTextTransaction2.setText("0");
final Button button = findViewById(R.id.NewTransactionButtonSave);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent replyIntent = new Intent();
if (TextUtils.isEmpty(mEditTextTransaction.getText())){
Toast.makeText(getApplicationContext(), R.string.TransactionNameMissing, Toast.LENGTH_LONG).show();
return;
}
else if (TextUtils.isEmpty(mEditTextTransaction2.getText())){
mEditTextTransaction2.setText("0");
}
else {
String newtransactionname = mEditTextTransaction.getText().toString();
double newtransactionbalance = (Double.parseDouble(mEditTextTransaction2.getText().toString()));
replyIntent.putExtra(EXTRA_REPLY, newtransactionname);
replyIntent.putExtra(EXTRA_REPLY2, newtransactionbalance);
setResult(RESULT_OK, replyIntent);
}
finish();
}
});
}
}
我的 AsyncTask 插入方法：
private static class insertAsyncTask extends AsyncTask<Transaction, Void, Void> {
private TransactionDao mAsyncTaskDao;
insertAsyncTask(TransactionDao dao) {
mAsyncTaskDao = dao;
}
@Override
protected Void doInBackground(final Transaction... params) {
mAsyncTaskDao.insert(params[0]);
return null;
}
}
标记为错误的行是这一行：mAsyncTaskDao.insert(params[0]);
错误：
07-11 03:10:49.003 16307-16508/com.example.mainbuchhaltung E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #4
Process: com.example.mainbuchhaltung, PID: 16307
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.database.sqlite.SQLiteConstraintException: FOREIGN KEY constraint failed (code 787)
#################################################################
Error Code : 787 (SQLITE_CONSTRAINT_FOEIGNKEY)
Caused By : Abort due to constraint violation.
(FOREIGN KEY constraint failed (code 787))
#################################################################
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:915)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.arch.persistence.db.framework.FrameworkSQLiteStatement.executeInsert(FrameworkSQLiteStatement.java:50)
at android.arch.persistence.room.EntityInsertionAdapter.insert(EntityInsertionAdapter.java:64)
at com.example.mainbuchhaltung.Transaction.TransactionDao_Impl.insert(TransactionDao_Impl.java:96)
at com.example.mainbuchhaltung.Transaction.TransactionRepository$insertAsyncTask.doInBackground(TransactionRepository.java:64)
at com.example.mainbuchhaltung.Transaction.TransactionRepository$insertAsyncTask.doInBackground(TransactionRepository.java:54)
at android.os.AsyncTask.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
... 4 more
创建事务和成员实体之间的关系，如前所述
然后，一旦您获得交易数据（交易名称和金额），您就必须将数据传递给 MemberList activity，例如 here
现在，在您的会员列表屏幕中完成您的选择后，请遵循以下过程：
假设您在字符串中有成员 ID。
String memberIds = "12,18,25,27,30";
现在您必须创建所有成员 ID 分开的交易实体对象，并将其插入交易的 table 中，如下所示。
String[] memberArray = memberIds.split(",", memberIds.length());
for(String memberId : memberArray){
// transactionName & transactionAmount which you received in the bundle from add transaction activity
Transaction objTransaction = new Transaction(transactionName, transactionAmount);
objTransaction.setMemberId(Long.parseLong(memberId));
// Insert data into your database
mTransactionViewModel.insert(objTransaction);
}
它将为 "transaction_table" table 中的每个 memberId 创建一个单独的条目，具有一对一的关系。
您可以通过执行上述查询来获取交易数据