我的app数据库类

@Database(entities = {Detail.class}, version = Constant.DATABASE_VERSION)
public abstract class AppDatabase extends RoomDatabase {

    private static AppDatabase INSTANCE;

    public abstract FavoritesDao favoritesDao();

    public static AppDatabase getAppDatabase(Context context) {
        if (INSTANCE == null) {
            INSTANCE =
                    Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, Constant.DATABASE).allowMainThreadQueries().build();

                    //Room.inMemoryDatabaseBuilder(context.getApplicationContext(),AppDatabase.class).allowMainThreadQueries().build();
        }
        return INSTANCE;
    }

    public static void destroyInstance() {
        INSTANCE = null;
    }
}

Gradle自由:

 compile "android.arch.persistence.room:runtime:+"   
 annotationProcessor "android.arch.persistence.room:compiler:+"

当我请求实例时,它会给出这个错误,AppDatabase_Impl不存在 在我的应用课上

public class APp extends Application {

    private boolean appRunning = false;

    @Override
    public void onCreate() {
        super.onCreate();
        AppDatabase.getAppDatabase(this); //--AppDatabase_Impl does not exist

    }   

}

当前回答

在2023年1月,我在重构我的代码以使用ServiceLocator类后遇到了类似的问题。

为了解决这个问题,我在更衣室里玩了很多次。它适用于2.5.0-alpha02

Version_room = "2.5.0-alpha02" <——build。gradle(项目)

 //Room
implementation "androidx.room:room-runtime:$version_room"
kapt "androidx.room:room-compiler:$version_room"
// optional - Kotlin Extensions and Coroutines support for Room
implementation "androidx.room:room-ktx:$version_room"
implementation("androidx.room:room-guava:$version_room")

我在Android Eel 2020.1.1上运行以下程序:

Version_kotlin = "1.7.21" Version_android_gradle_plugin = "4.0.1"

其他回答

以上答案都不起作用,我注意到当我使用2.3.0或2.4.2版本的房间时,这个问题仍然存在。但是,当我应用它时,2.5.0-alpha01版本工作得很好。

build.gradle:应用程序

def roomVersion = '2.5.0-alpha01'
implementation "androidx.room:room-ktx:$roomVersion"
kapt "androidx.room:room-compiler:$roomVersion"
testImplementation "android.arch.persistence.room:testing:$roomVersion"

除了思念

annotationProcessor“android.arch.persistence.room:编译器:. x.x.x”

我还错过了在课上添加下面的注释

@Entity(tableName = "mytablename")

使用下面的gradle链接:

compile 'android.arch.persistence.room:runtime:1.0.0-alpha9'
annotationProcessor 'android.arch.persistence.room:compiler:1.0.0-alpha9'

你需要创建一个不同的单例类,并从那里获取AppDatabase,如下所示:

RoomDB.java

public class RoomDB {

private static RoomDB INSTANCE;

public static AppDatabase getInstance(Context context) {
    if (INSTANCE == null) {
        INSTANCE =
                Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, Constant.DATABASE).allowMainThreadQueries().build();

                //Room.inMemoryDatabaseBuilder(context.getApplicationContext(),AppDatabase.class).allowMainThreadQueries().build();
    }
    return INSTANCE;
}

public static void destroyInstance() {
    INSTANCE = null;
}

App.java

public class App extends Application {

private boolean appRunning = false;

@Override
public void onCreate() {
    super.onCreate();
    RoomDB.getInstance(this); //This will provide AppDatabase Instance
}

在我的kotlin应用程序中,我只是在我的构建顶部添加了以下一行。Gradle文件:

apply plugin: 'kotlin-kapt'

以及依赖项部分的下面一行:

kapt "androidx.room:room-compiler:2.2.5"

我希望它能解决你的问题。

确保在build.gradle中为room添加正确的依赖项

ext {
   roomVersion = '2.1.0-alpha06'
}

// Room components
implementation "androidx.room:room-runtime:$rootProject.roomVersion"
implementation "androidx.room:room-ktx:$rootProject.roomVersion"
kapt "androidx.room:room-compiler:$rootProject.roomVersion"
androidTestImplementation "androidx.room:room-testing:$rootProject.roomVersion"

在上面这条线下面

apply plugin: 'kotlin-kapt'