小编Mem*_*maz的帖子

我正在尝试实现房间数据库，我已经完成了官方网站上的步骤，“AppDatabase.java”文件如下：

import android.content.Context;
import androidx.room.Database;
import androidx.room.Room;
import androidx.room.RoomDatabase;

@Database(entities = {User.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {

    public static AppDatabase instance;
    public static synchronized AppDatabase getInstance(Context context){
        if (instance==null){
            instance = Room.databaseBuilder(context.getApplicationContext(),
                    AppDatabase.class, "app_database").fallbackToDestructiveMigration().build();
        }
        return instance;
    }
}

以及我用于房间的依赖项：

    // Room Database
    def room_version = "2.4.2"

    implementation "androidx.room:room-runtime:$room_version"
    annotationProcessor "androidx.room:room-compiler:$room_version"

    // optional - RxJava2 support for Room
    implementation "androidx.room:room-rxjava2:$room_version"

    // optional - RxJava3 support for Room
    implementation "androidx.room:room-rxjava3:$room_version"

    // optional - Guava …