最是人间留不住，朱颜辞镜花辞树。这篇文章主要讲述错误：不兼容的类型：如果使用android室（（__cursor.isNull（null）），则无法转换为int相关的知识，希望能为你提供帮助。
我正在为我的android数据库使用空间。在这里，我在Customer和ServiceProvider类之间有很多对很多的关系，我曾用this tutorial来做到这一点，但在编译后却收到此错误：
/ home / omid / IntelliJIDEAProjects / Accounting / app / build / generated / ap_genic_sources / debug / out / com / omidmsl / accounting / db / CustomerDAO_Impl.java：69：错误：不兼容的类型：无法转换为int如果（！_cursor.isNull（null））{并且提到此代码CustomerDAO_Impl.java（由编译器创建）：
package com.omidmsl.accounting.db;
import android.database.Cursor;
import androidx.collection.ArrayMap;
import androidx.room.RoomDatabase;
import androidx.room.RoomSQLiteQuery;
import androidx.room.util.CursorUtil;
import androidx.room.util.DBUtil;
import androidx.room.util.StringUtil;
import com.omidmsl.accounting.models.Business;
import com.omidmsl.accounting.models.Customer;
import com.omidmsl.accounting.models.serviceprovider.CustomerOfServiceProvider;
import java.lang.Override;
import java.lang.String;
import java.lang.StringBuilder;
import java.lang.SuppressWarnings;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
@SuppressWarnings({"unchecked", "deprecation"})
public final class CustomerDAO_Impl implements CustomerDAO {
private final RoomDatabase __db;
public CustomerDAO_Impl(RoomDatabase __db) {
this.__db = __db;
}@Override
public List<
Customer>
getCustomers() {
final String _sql = "SELECT * FROM Customer";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 0);
__db.assertNotSuspendingTransaction();
final Cursor _cursor = DBUtil.query(__db, _statement, false, null);
try {
final int _cursorIndexOfCustomerName = CursorUtil.getColumnIndexOrThrow(_cursor, "customerName");
final int _cursorIndexOfPhoneNumber = CursorUtil.getColumnIndexOrThrow(_cursor, "phoneNumber");
final List<
Customer>
_result = new ArrayList<
Customer>
(_cursor.getCount());
while(_cursor.moveToNext()) {
final Customer _item;
_item = new Customer();
final String _tmpCustomerName;
_tmpCustomerName = _cursor.getString(_cursorIndexOfCustomerName);
_item.setCustomerName(_tmpCustomerName);
final String _tmpPhoneNumber;
_tmpPhoneNumber = _cursor.getString(_cursorIndexOfPhoneNumber);
_item.setPhoneNumber(_tmpPhoneNumber);
_result.add(_item);
}
return _result;
} finally {
_cursor.close();
_statement.release();
}
}@Override
public List<
CustomerOfServiceProvider>
getCustomersOfServiceProvider() {
final String _sql = "SELECT * FROM Customer";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 0);
__db.assertNotSuspendingTransaction();
__db.beginTransaction();
try {
final Cursor _cursor = DBUtil.query(__db, _statement, true, null);
try {
final int _cursorIndexOfPhoneNumber = CursorUtil.getColumnIndexOrThrow(_cursor, "phoneNumber");
final ArrayMap<
String, ArrayList<
Customer>
>
_collectionCustomers = new ArrayMap<
String, ArrayList<
Customer>
>
();
while (_cursor.moveToNext()) {
if (!_cursor.isNull(null)) {
final String _tmpKey = _cursor.getString(null);
ArrayList<
Customer>
_tmpCustomersCollection = _collectionCustomers.get(_tmpKey);
if (_tmpCustomersCollection == null) {
_tmpCustomersCollection = new ArrayList<
Customer>
();
_collectionCustomers.put(_tmpKey, _tmpCustomersCollection);
}
}
}
_cursor.moveToPosition(-1);
__fetchRelationshipCustomerAscomOmidmslAccountingModelsCustomer(_collectionCustomers);
final List<
CustomerOfServiceProvider>
_result = new ArrayList<
CustomerOfServiceProvider>
(_cursor.getCount());
while(_cursor.moveToNext()) {
final CustomerOfServiceProvider _item;
final Business _tmpServiceProvider;
if (! (_cursor.isNull(_cursorIndexOfPhoneNumber))) {
_tmpServiceProvider = new Business();
final String _tmpPhoneNumber;
_tmpPhoneNumber = _cursor.getString(_cursorIndexOfPhoneNumber);
_tmpServiceProvider.setPhoneNumber(_tmpPhoneNumber);
}else{
_tmpServiceProvider = null;
}
ArrayList<
Customer>
_tmpCustomersCollection_1 = null;
if (!_cursor.isNull(null)) {
final String _tmpKey_1 = _cursor.getString(null);
_tmpCustomersCollection_1 = _collectionCustomers.get(_tmpKey_1);
}
if (_tmpCustomersCollection_1 == null) {
_tmpCustomersCollection_1 = new ArrayList<
Customer>
();
}
_item = new CustomerOfServiceProvider();
_item.setServiceProvider(_tmpServiceProvider);
_item.setCustomers(_tmpCustomersCollection_1);
_result.add(_item);
}
__db.setTransactionSuccessful();
return _result;
} finally {
_cursor.close();
_statement.release();
}
} finally {
__db.endTransaction();
}
}@Override
public List<
Customer>
getCustomer(final String cName) {
final String _sql = "SELECT * FROM Customer WHERE customerName = ?";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 1);
int _argIndex = 1;
if (cName == null) {
_statement.bindNull(_argIndex);
} else {
_statement.bindString(_argIndex, cName);
}
__db.assertNotSuspendingTransaction();
final Cursor _cursor = DBUtil.query(__db, _statement, false, null);
try {
final int _cursorIndexOfCustomerName = CursorUtil.getColumnIndexOrThrow(_cursor, "customerName");
final int _cursorIndexOfPhoneNumber = CursorUtil.getColumnIndexOrThrow(_cursor, "phoneNumber");
final List<
Customer>
_result = new ArrayList<
Customer>
(_cursor.getCount());
while(_cursor.moveToNext()) {
final Customer _item;
_item = new Customer();
final String _tmpCustomerName;
_tmpCustomerName = _cursor.getString(_cursorIndexOfCustomerName);
_item.setCustomerName(_tmpCustomerName);
final String _tmpPhoneNumber;
_tmpPhoneNumber = _cursor.getString(_cursorIndexOfPhoneNumber);
_item.setPhoneNumber(_tmpPhoneNumber);
_result.add(_item);
}
return _result;
} finally {
_cursor.close();
_statement.release();
}
}private void __fetchRelationshipCustomerAscomOmidmslAccountingModelsCustomer(final ArrayMap<
String, ArrayList<
Customer>
>
_map) {
final Set<
String>
__mapKeySet = _map.keySet();
if (__mapKeySet.isEmpty()) {
return;
}
// check if the size is too big, if so divide;
if(_map.size() >
RoomDatabase.MAX_BIND_PARAMETER_CNT) {
ArrayMap<
String, ArrayList<
Customer>
>
_tmpInnerMap = new ArrayMap<
String, ArrayList<
Customer>
>
(androidx.room.RoomDatabase.MAX_BIND_PARAMETER_CNT);
int _tmpIndex = 0;
int _mapIndex = 0;
final int _limit = _map.size();
while(_mapIndex <
_limit) {
_tmpInnerMap.put(_map.keyAt(_mapIndex), _map.valueAt(_mapIndex));
_mapIndex++;
_tmpIndex++;
if(_tmpIndex == RoomDatabase.MAX_BIND_PARAMETER_CNT) {
__fetchRelationshipCustomerAscomOmidmslAccountingModelsCustomer(_tmpInnerMap);
_tmpInnerMap = new ArrayMap<
String, ArrayList<
Customer>
>
(RoomDatabase.MAX_BIND_PARAMETER_CNT);
_tmpIndex = 0;
}
}
if(_tmpIndex >
0) {
__fetchRelationshipCustomerAscomOmidmslAccountingModelsCustomer(_tmpInnerMap);
}
return;
}
StringBuilder _stringBuilder = StringUtil.newStringBuilder();
_stringBuilder.append("SELECT `Customer`.`customerName` AS `customerName`,`Customer`.`phoneNumber` AS `phoneNumber`,_junction.`businessName` FROM `Service` AS _junction INNER JOIN `Customer` ON (_junction.`customerName` = `Customer`.`customerName`) WHERE _junction.`businessName` IN (");
final int _inputSize = __mapKeySet.size();
StringUtil.appendPlaceholders(_stringBuilder, _inputSize);
_stringBuilder.append(")");
final String _sql = _stringBuilder.toString();
final int _argCount = 0 + _inputSize;
final RoomSQLiteQuery _stmt = RoomSQLiteQuery.acquire(_sql, _argCount);
int _argIndex = 1;
for (String _item : __mapKeySet) {
if (_item == null) {
_stmt.bindNull(_argIndex);
} else {
_stmt.bindString(_argIndex, _item);
}
_argIndex ++;
}
final Cursor _cursor = DBUtil.query(__db, _stmt, false, null);
try {
final int _itemKeyIndex = 2;
// _junction.businessName;
if (_itemKeyIndex == -1) {
return;
}
final int _cursorIndexOfCustomerName = CursorUtil.getColumnIndex(_cursor, "customerName");
final int _cursorIndexOfPhoneNumber = CursorUtil.getColumnIndex(_cursor, "phoneNumber");
while(_cursor.moveToNext()) {
if (!_cursor.isNull(_itemKeyIndex)) {
final String _tmpKey = _cursor.getString(_itemKeyIndex);
ArrayList<
Customer>
_tmpRelation = _map.get(_tmpKey);
if (_tmpRelation != null) {
final Customer _item_1;
_item_1 = new Customer();
if (_cursorIndexOfCustomerName != -1) {
final String _tmpCustomerName;
_tmpCustomerName = _cursor.getString(_cursorIndexOfCustomerName);
_item_1.setCustomerName(_tmpCustomerName);
}
if (_cursorIndexOfPhoneNumber != -1) {
final String _tmpPhoneNumber;
_tmpPhoneNumber = _cursor.getString(_cursorIndexOfPhoneNumber);
_item_1.setPhoneNumber(_tmpPhoneNumber);
}
_tmpRelation.add(_item_1);
}
}
}
} finally {
_cursor.close();
}
}
}这是我的其余代码：Customer.java：
package com.omidmsl.accounting.models;
import androidx.annotation.NonNull;
import androidx.room.Entity;
import androidx.room.PrimaryKey;
@Entity(tableName = "Customer")
public class Customer {public static final String KEY_NAME = "customer_name";
public static final String KEY_PHONE_NUMBER = "phone_number";
@NonNull
@PrimaryKey
private String customerName;
private String phoneNumber;
public String getCustomerName() {
return customerName;
}public void setCustomerName(String customerName) {
this.customerName = customerName;
}public String getPhoneNumber() {
return phoneNumber;
}public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
}
CustomerDAO.java：
package com.omidmsl.accounting.db;
import androidx.room.Dao;
import androidx.room.Query;
import androidx.room.Transaction;
import com.omidmsl.accounting.models.Customer;
import com.omidmsl.accounting.models.serviceprovider.CustomerOfServiceProvider;
import java.util.List;
@Dao
public interface CustomerDAO {@Query("SELECT * FROM Customer")
public List<
Customer>
getCustomers();
@Transaction
@Query("SELECT * FROM Customer")
public List<
CustomerOfServiceProvider>
getCustomersOfServiceProvider();
@Query("SELECT * FROM Customer WHERE customerName = :cName")
public List<
Customer>
getCustomer(String cName);
}Business.java：
package com.omidmsl.accounting.models;
import androidx.annotation.NonNull;
import androidx.room.Entity;
import androidx.room.*;
@Entity(tableName = "Business")
public class Business {public static final String KEY_TYPE = "type";
public static final String KEY_NAME = "business_name";
public static final String KEY_PHONE_NUMBER = "phone_number";
private int type;
@PrimaryKey
@NonNull
private String businessName;
private String phoneNumber;
@Ignore
private long costs;
@Ignore
private long buys;
public Business(int type) {
this.type = type;
}public int getType() {
return type;
}public void setType(int type) {
this.type = type;
}public Business() {
businessName = "";
}public String getBusinessName() {
return businessName;
}public void setBusinessName(String businessName) {
this.businessName = businessName;
}public String getPhoneNumber() {
return phoneNumber;
}public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}public long getCosts() {
return costs;
}public void setCosts(long costs) {
this.costs = costs;
}public long getBuys() {
return buys;
}public void setBuys(long buys) {
this.buys = buys;
}
}ServiceProviderDAO.java：
package com.omidmsl.accounting.db;
import androidx.room.Dao;
import androidx.room.Query;
import androidx.room.Transaction;
import com.omidmsl.accounting.models.serviceprovider.ServiceProviderOfCustomer;
import java.util.List;
@Dao
public interface ServiceProviderDAO {
@Transaction
@Query("SELECT * FROM Business")
public List<
ServiceProviderOfCustomer>
getServiceProvidersOfCustomer();
}
CustomersOfServiceProvider.java：
package com.omidmsl.accounting.models.serviceprovider;
import androidx.room.*;
import com.omidmsl.accounting.models.Business;
import com.omidmsl.accounting.models.Customer;
import java.util.List;
public class CustomerOfServiceProvider {
@Embedded
private Business serviceProvider;
@Relation(
parentColumn = "businessName",
entityColumn = "customerName",
associateBy = @Junction(Service.class)
)
private List<
Customer>
customers;
public Business getServiceProvider() {
return serviceProvider;
}public void setServiceProvider(Business serviceProvider) {
this.serviceProvider = serviceProvider;
}public List<
Customer>
getCustomers() {
return customers;
}public void setCustomers(List<
Customer>
customers) {
this.customers = customers;
}
}
请帮助我
答案【错误（不兼容的类型：如果使用android室（（__cursor.isNull（null）），则无法转换为int）】谢谢@ianhanniballake。问题解决了！。在CustomerDAO文件中，我发现此问题：
@Transaction
@Query("SELECT * FROM Customer")
public List<
CustomerOfServiceProvider>
getCustomersOfServiceProvider();
此列表的类型必须是ServiceProvidersOfCustomer：
@Transaction
@Query("SELECT * FROM Customer")
public List<
ServiceProviderOfCustomer>
getServiceProvidersOfCustomer();
推荐阅读
- ApplicationContext或Activity Context是否适合Adapter（）
- 为什么Apple Accelerate框架有时会很慢（）
- 在Google App Script中使用导入的模块
- 在apply函数中访问索引
- 如何正确使用mapPartitions函数
- 找不到adb请设置ANDROID_HOME异常 - Visual Studio
- Mac中的Android工作室路径错误
- 如何从app delegate访问NSViewController（）
- 如何从Android中的图像数组创建视频（）