如何创建SQLite数据库并在Kotlin中的屏幕之间使用它与Jetpack Compose(启动应用程序时出错)?

wbrvyc0a  于 2023-10-23  发布在  SQLite
关注(0)|答案(1)|浏览(92)

我正在使用Kotlin(Jetpack Compose)开发一个简单的应用程序,在解决运行应用程序时出现的问题时遇到了麻烦。从我个人的理解,这是不是那么好,在我看来,功能应该工作的预期,但我仍然不确定是否有一个问题,在代码本身或依赖关系。根据logcat,似乎我试图在MainActivity中声明的数据库没有被识别/创建。我试图通过使用ChatGPT处理依赖关系来解决这个问题,但我只遇到了更多的错误来修复,这个错误已经花了一段时间。当我尝试运行应用程序时,它会崩溃。如果有人知道如何解决这个问题,我将不胜感激。

    • 数据库屏幕**
@Composable fun DatabaseScreen( navController: NavController, sliderValue: Float, userRepository: UserRepository ) { var userCount by remember { mutableStateOf(0) } var resultText by remember { mutableStateOf("") }

    Column(
        modifier = Modifier
            .fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        Button(
            onClick = {
                CoroutineScope(Dispatchers.IO).launch {
                    val startTime = System.nanoTime()

                    for (i in 0 until (sliderValue * sliderValue * 10).toInt()) {
                        val age = i % 17 + 1
                        userRepository.insertUser(User(age = age))
                    }

                    val endTime = System.nanoTime()
                    val duration = endTime - startTime

                    // Update UI on the main thread
                    withContext(Dispatchers.Main) {
                        resultText = "Added users: ${(sliderValue * sliderValue * 10).toInt()} in $duration nanoseconds"
                    }
                }
            }
}
    • 数据库类和函数**
@Entity(tableName = "user")
data class User(
    @PrimaryKey(autoGenerate = true) val id: Long = 0,
    val age: Int
)

@Database(entities = [User::class], version = 1)
abstract class AppDatabase : RoomDatabase() {
    abstract fun userDao(): UserDao
}

@Dao
interface UserDao {
    @Insert
    suspend fun insertUser(user: User)

    @Query("SELECT * FROM user")
    suspend fun getAllUsers(): List<User>

    @Query("DELETE FROM user")
    suspend fun clearDatabase()
}

class UserRepository(private val userDao: UserDao) {
    suspend fun insertUser(user: User) {
        userDao.insertUser(user)
    }

    suspend fun getAllUsers(): List<User> {
        return userDao.getAllUsers()
    }

    suspend fun clearDatabase() {
        userDao.clearDatabase()
    }
}
    • 主要活动**
override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            val database = Room.databaseBuilder(
                applicationContext,
                AppDatabase::class.java,
                "my_database"
            ).build()

            val userRepository = UserRepository(database.userDao())
            setContent {
                var navController = rememberNavController()

                NavHost(navController = navController, startDestination = "mainScreen") {
                    composable("mainScreen") { MyApp(navController) }
                    composable("Screen0") {
                        UIScreen(navController, 5f)
                    }
                    composable("Screen1") {
                        AnimationScreen(navController, 5f)
                    }
                    composable("Screen2") {
                        ArithmeticLogicalScreen(navController, 4f)
                    }
                    composable("Screen3") {
                        DatabaseScreen(navController, 5f,userRepository)
                    }
                    composable("Screen4") {
                        FeaturesScreen(navController, 5f)
                    }
                }
            }
        }
    • 酒店LOGCAT**

致命异常:主要工艺:com. example. jurajappjetpack,PID:9583 java. lang. RuntimeException:无法启动活动PinterentInfo {com. example. jurajappjetpack/com. example. jurajappjetpack. MainActivity}:java.lang.RuntimeException:找不到com.example.jurajappjetpack.MainActivity.AppDatabase的实现。您访问的页面不存在! app. ActivityThread. performLaunchActivity(ActivityThread.java:2913)at android. app. ActivityThread.在android上安装LaunchActivity(ActivityThread.java:3048)。app. servertransaction。LaunchActivityItem。execute(LaunchActivityItem.java:78)at android. app. servertransaction。TransactionExecutor。android上的executeCallbacks(transactionExecutor.java:108)。app. servertransaction。TransactionExecutor。execute(transactionExecutor.java:68)at android. app. ActivityThread $H。在android上查看消息(ActivityThread.java:1808)。骨密度android上的dispatchMessage(Handler.java:106)。os. Looper.循环(Looper.java:193)在android. app. ActivityThread. main(ActivityThread.java:6669). lang。反思。方法。在com上调用(本地方法)。机器人内部的OS. RuntimeInit $ www.example.com 找不到com.example.jurajappjetpack.MainActivity.AppDatabase的实现。您访问的页面不存在!房间。房间。getGeneratedImplementation(Room. KT:58)在androidx上。房间。RoomDatabase $www.example.com(RoomDatabase.第1357章在一起举个例子。jurajappjetpack.主要活动。onCreate(MainActivity. KT:125)在Android上。应用程序。活动。performCreate(Activity.java:7136)at android.应用程序。活动。performCreate(Activity.java:7127)at android. app.仪器 Jmeter 。callActivityOnCreate(Instrumentation.java:1271)at android. app. ActivityThread. performLaunchActivity(ActivityThread.java:2893)at android. app. ActivityThread.在android上安装LaunchActivity(ActivityThread.java:3048)。app. servertransaction。LaunchActivityItem。execute(LaunchActivityItem.java:78)at android. app. servertransaction。TransactionExecutor。android上的executeCallbacks(transactionExecutor.java:108)。app. servertransaction。TransactionExecutor。execute(transactionExecutor.java:68)at android. app. ActivityThread $H。在android上查看消息(ActivityThread.java:1808)。骨密度android上的dispatchMessage(Handler.java:106)。os. Looper.循环(Looper.java:193)在android. app. ActivityThread. main(ActivityThread.java:6669). lang。反思。方法。在com上调用(本地方法)。机器人内部的OS. RuntimeInit $www.example.com(RuntimeInit.java:493)at com. android. internal. os. ZygoteInit. main(ZygoteInit.java:858)

    • BUILD. GRADLE项目级别**
plugins { id("com.android.application") version "8.1.1" apply false
 id("org.jetbrains.kotlin.android") version "1.8.10" apply false }
    • 酒店BUILD. GRADLE MONTHLE LEVEL,巴塞罗那**
plugins {
id("com.android.application")
id("org.jetbrains.kotlin.android")

}

android {
namespace = "com.example.jurajappjetpack"
compileSdk = 33

defaultConfig {
    applicationId = "com.example.jurajappjetpack"
    minSdk = 28
    targetSdk = 33
    versionCode = 1
    versionName = "1.0"

    testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
    vectorDrawables {
        useSupportLibrary = true
    }
}
buildTypes {
    release {
        isMinifyEnabled = false
        proguardFiles(
            getDefaultProguardFile("proguard-android-optimize.txt"),
            "proguard-rules.pro"
        )
    }
}
compileOptions {
    sourceCompatibility = JavaVersion.VERSION_1_8
    targetCompatibility = JavaVersion.VERSION_1_8
}
kotlinOptions {
    jvmTarget = "1.8"
}
buildFeatures {
    compose = true
}
composeOptions {
    kotlinCompilerExtensionVersion = "1.4.3"
}
packaging {
    resources {
        excludes += "/META-INF/{AL2.0,LGPL2.1}"
    }
}

}

dependencies {

implementation("androidx.core:core-ktx:1.9.0")
implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.6.1")
implementation("androidx.activity:activity-compose:1.7.0")
implementation(platform("androidx.compose:compose-bom:2023.03.00"))
implementation("androidx.compose.ui:ui")
implementation("androidx.compose.ui:ui-graphics")
implementation("androidx.compose.ui:ui-tooling-preview")
implementation("androidx.compose.material3:material3")
implementation("com.google.android.material:material:1.9.0")
implementation("androidx.room:room-ktx:2.5.2")
testImplementation("junit:junit:4.13.2")
androidTestImplementation("androidx.test.ext:junit:1.1.5")
androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
androidTestImplementation(platform("androidx.compose:compose-bom:2023.03.00"))
androidTestImplementation("androidx.compose.ui:ui-test-junit4")
debugImplementation("androidx.compose.ui:ui-tooling")
debugImplementation("androidx.compose.ui:ui-test-manifest")
implementation ("androidx.navigation:navigation-compose:2.4.0")
implementation("androidx.compose.animation:animation-core")
implementation ("com.google.android.gms:play-services-location:18.0.0")
implementation ("androidx.activity:activity-ktx:1.3.1")
implementation ("androidx.fragment:fragment-ktx:1.4.0")
implementation ("androidx.lifecycle:lifecycle-runtime-ktx:2.4.0")
implementation ("androidx.camera:camera-camera2:1.1.0-beta01")
implementation ("androidx.camera:camera-lifecycle:1.1.0-beta01")
implementation ("androidx.room:room-runtime:2.5.2")
annotationProcessor ("androidx.room:room-compiler:2.5.2")

}

odopli94

odopli941#

首先将kapt插件添加到模块构建gradle中,例如。(适用于所有3个插件):-

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    id 'kotlin-kapt'
}

然后将annotationProcessor ("androidx.room:room-compiler:2.5.2")更改为

kapt 'androidx.room:room-compiler:2.5.2'

annotationProcessor用于处理java kapt或ksp用于Kotlin。它是生成Java代码的处理器,因此代码不存在。

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