任务'：app：kaptDebugKotlin'的错误MyApplication执行失败

Question

我的MyApplication有错误，每次看到我构建的项目出现，我觉得和房间有关系但是我解决不了

日志：

Task :app:kaptDebugKotlin FAILED
C:\Users\matheus.correa_est\Desktop\Pokedex- 
master\app\build\tmp\kapt3\stubs\debug\com\example\pokedex\MyApplication.java:13: error: cannot find 
symbol
    public final AppDataBase getDataBase() {
                 ^
  symbol:   class AppDataBase
  location: class MyApplication
FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:kaptDebugKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.gradle.internal.KaptExecution
   > java.lang.reflect.InvocationTargetException (no error message)

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more 
log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.5/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 2s
24 actionable tasks: 1 executed, 23 up-to-date

MyApplication.java

package com.example.pokedex;

import java.lang.System;

d2 = {"Lcom/example/pokedex/MyApplication;", "Landroid/app/Application;", "()V", "dataBase", 
"LAppDataBase;", "getDataBase", "()LAppDataBase;", "dataBase$delegate", "Lkotlin/Lazy;", 
"repository", "Lcom/example/pokedex/repository/PokedexRepository;", "getRepository", " 
()Lcom/example/pokedex/repository/PokedexRepository;", "repository$delegate", "app_debug"})
public class MyApplication extends android.app.Application {
    @org.jetbrains.annotations.NotNull()
    private final kotlin.Lazy dataBase$delegate = null;
    @org.jetbrains.annotations.NotNull()
    private final kotlin.Lazy repository$delegate = null;

    @org.jetbrains.annotations.NotNull()
    public final AppDataBase getDataBase() {   //  line where the error is being shown in the log
        return null;
    }

    @org.jetbrains.annotations.NotNull()
    public final com.example.pokedex.repository.PokedexRepository getRepository() {
        return null;
    }

    public MyApplication() {
        super();
    }
}

类应用数据库

@Database(entities = [PokemonItem::class], version = 1, exportSchema = false)
abstract class AppDataBase: RoomDatabase() {
abstract fun pokemonDAO(): PokemonDAO

companion object {
    @Volatile
    private var INSTANCE: AppDataBase? = null
    fun getDataBase(context: Context): AppDataBase {
        return INSTANCE ?: synchronized(this) {
            val instance = Room.databaseBuilder(
                context.applicationContext,
                AppDataBase::class.java,
                "pokemon-db"
            )
                .build()
            INSTANCE = instance
            instance
        }
    }
   }
 }

自从我将 AppDatabase 用于数据持久性以来，此错误开始发生，我认为问题出在 gradle 中，但据我所见，我无法通过其版本修复它

Answer 1

看起来很不对劲。只需关注谷歌文档：

https://developer.android.com/training/data-storage/room

Answer 2

这是一个不同的基本应用程序的工作示例，它混合了 Kotlin 和 Java，并包含一个 Room 数据库。它基于您的代码的基本思想/意图。然后，您可以对此进行扩展。

Kotlin 中的 PokemonItem 实体（表）类：-

@Entity
class PokemonItem {
    @PrimaryKey
    var id: Long? = null
    var name: String = ""
}

PokemonDao 接口 (Kotlin) 只需一个查询即可提取所有内容（因此使用它会创建数据库）：-

@Dao
public interface PokemonDao {

    @Query("SELECT * FROM pokemonitem")
    fun getAllFromPokemonItem(): List<PokemonItem>
}

一个简化的 AppDatabase 抽象类（Kotlin）（不是单例）：-

@Database(entities = arrayOf(PokemonItem::class),version = 1)
abstract class AppDatabase: RoomDatabase() {
    abstract fun pokeMonDao(): PokemonDao
}

一个 Activity (Java) 使用上述方法提取所有（没有添加，因为没有添加）PokemonItems：-

public class MainActivity extends AppCompatActivity {

    AppDatabase pokemonDB;
    PokemonDao pokemonDao;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        pokemonDB = Room.databaseBuilder(
                this,
                AppDatabase.class,
                "poekmon.db"
        )
                .allowMainThreadQueries()
                .build();
        pokemonDao = pokemonDB.pokeMonDao();
        List<PokemonItem> pokemonItems = pokemonDao.getAllFromPokemonItem();
    }
}

结果

运行然后使用 Database Inspector (Android Studio) 显示：-

即它已编译并运行，并且由于尝试打开数据库而创建了数据库。

• 请注意，.allowMainThreadQueries 允许它在主线程上运行，并且为简洁起见。

:-

Answer 3

问题解决了，这个类不在包中，因此它没有导入，所以我指出了错误

package com.example.pokedex.dao