错误（不兼容的类型：如果使用android室（（__cursor.isNull（null）），则无法转换为int） _android

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：