Room IllegalArgumentException:无法将int转换为Element [英] Room IllegalArgumentException: intcannot be converted to an Element

问题描述

尝试编译项目时出现此错误:

I'm having this error when trying to compile the project:

错误:任务':app:compileDebugJavaWithJavac'的执行失败. java.lang.IllegalArgumentException:无法将int转换为Element

Error:Execution failed for task ':app:compileDebugJavaWithJavac'. java.lang.IllegalArgumentException: intcannot be converted to an Element

此警告:

警告:注释处理器"android.arch.persistence.room.RoomProcessor"支持的源版本"RELEASE_7"小于-source"1.8"

Warning:Supported source version 'RELEASE_7' from annotation processor 'android.arch.persistence.room.RoomProcessor' less than -source '1.8'

这些是与我的数据库相关的类:

These are my database related classes:

@Entity(tableName = "users")
public class SerializedUser {

    @PrimaryKey(autoGenerate = true)
    private int id;

    @ColumnInfo(name = "first_name")
    private String firstName;

    @ColumnInfo(name = "last_name")
    private String lastName;

    @ColumnInfo(name = "username")
    private String username;

    public SerializedUser(int id, String firstName, String lastName, String username) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.username = username;
    }

    public int getId() {
        return id;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public String getUsername() {
        return username;
    }
}

@android.arch.persistence.room.Database(entities = {SerializedUser.class}, version = 4)
public abstract class Database extends RoomDatabase {
    public abstract UserDao userDao();

    private static final String DATABASE_NAME = "weather";

    // For Singleton instantiation
    private static final Object LOCK = new Object();
    private static volatile Database i;

    public static Database init(Context context) {
        if (i == null) {
            synchronized (LOCK) {
                if (i == null) {
                    i = Room.databaseBuilder(context.getApplicationContext(),
                            Database.class, Database.DATABASE_NAME)
                            .fallbackToDestructiveMigration().build();
                }
            }
        }
        return i;
    }

    public static boolean isInited(){
        return i != null;
    }

    public static Database getInstance(){
        if(i == null)
            throw new NullPointerException("Database.getInstance called when Database not initialized");
        return i;
    }
}

@Dao
public abstract class UserDao {

    Converters converters;

    public void inject(Converters converters) {
        this.converters = converters;
    }

    @Insert(onConflict = REPLACE)
    public abstract void saveNow(SerializedUser user);

    @Delete
    public abstract void deleteNow(int id);

    @Query("DELETE FROM users")
    public abstract void deleteAllNow();

    @Query("SELECT * FROM users")
    public abstract List<SerializedUser> getAllNow();

    @Query("SELECT * FROM users ORDER BY last_name ASC")
    public abstract LivePagedListProvider<Integer, SerializedUser> usersByLastName();
}

因此在尝试实现数据库类时发生错误?在SerializedUser上的id并不是问题，我已将其注释掉，问题仍然相同.尝试清理并重建项目，然后重新启动Android Studio(无效并重新启动).

So the error happens when it tries to implement the database classes? That id on SerializedUser is not the problem, I have commented it out, the problem was still the same. Tried to clean and rebuild the project and restarted Android Studio (invalidate and restart).

推荐答案

删除

@Delete
public abstract void deleteNow(int id);

从您的Dao可以正常工作

from your Dao it will work

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