未解决的参考:在 viewModelScope 中启动
Unresolved reference: launch in viewModelScope
我正在尝试使用 viewModelScope.launch 调用挂起函数,其中“启动”显示为未解析的引用。
这里是build.gradle
plugins {
id 'com.android.application'
id 'kotlin-android'
id 'kotlin-kapt'
}
android {
compileSdk 31
defaultConfig {
applicationId "com.example.mynotes"
minSdk 27
targetSdk 31
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled 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'
}
packagingOptions {
exclude 'META-INF/atomicfu.kotlin_module'
}
}
dependencies {
implementation "androidx.appcompat:appcompat:$rootProject.appCompatVersion"
implementation "androidx.activity:activity-ktx:$rootProject.activityVersion"
// Dependencies for working with Architecture components
// You'll probably have to update the version numbers in build.gradle (Project)
// Room components
implementation "androidx.room:room-ktx:$rootProject.roomVersion"
kapt "androidx.room:room-compiler:$rootProject.roomVersion"
androidTestImplementation "androidx.room:room-testing:$rootProject.roomVersion"
// Lifecycle components
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$rootProject.lifecycleVersion"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:$rootProject.lifecycleVersion"
implementation "androidx.lifecycle:lifecycle-common-java8:$rootProject.lifecycleVersion"
// Kotlin components
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$rootProject.coroutines"
api "org.jetbrains.kotlinx:kotlinx-coroutines-android:$rootProject.coroutines"
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.0'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.0'
// UI
implementation "androidx.constraintlayout:constraintlayout:$rootProject.constraintLayoutVersion"
implementation "com.google.android.material:material:$rootProject.materialVersion"
// Testing
testImplementation "junit:junit:$rootProject.junitVersion"
androidTestImplementation "androidx.arch.core:core-testing:$rootProject.coreTestingVersion"
androidTestImplementation ("androidx.test.espresso:espresso-core:$rootProject.espressoVersion", {
exclude group: 'com.android.support', module: 'support-annotations'
})
androidTestImplementation "androidx.test.ext:junit:$rootProject.androidxJunitVersion"
}
和ViewModel.kt
package com.example.mynotes
import android.app.Application
//import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.LiveData
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.*
class NotesViewModel(application: Application) : ViewModel() {
private val repository : NotesRepository
val allNotes : LiveData<List<Notes>>
init {
val dao = NotesDatabase.getDatabase(application).getNotesDao()
repository = NotesRepository(dao)
allNotes = repository.allNotes
}
fun deleteNotes(notes: Notes) = viewModelScope.launch(Dispatchers.IO) {
repository.delete(notes)
}
}
在 deleteNotes 函数中“viewModelScope.launch”显示未解决的引用:启动但在构建应用程序时没有错误,但我的应用程序在 运行.
时崩溃
我认为这是因为您声明变量的方式,因为您将其声明为直接函数,您可以尝试以下操作:
fun deleteNotes(notes: Notes) {
viewModelScope.launch(Dispatchers.IO) {
repository.delete(notes)
}
}
问题可能与方法声明并存储在内存中时,作用域还没有分配有关。
您使用的是哪个版本?
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.3.1"
尝试使用这种情况是不同的。
如果仍然无法识别,请尝试使缓存无效并重新启动
我正在尝试使用 viewModelScope.launch 调用挂起函数,其中“启动”显示为未解析的引用。
这里是build.gradle
plugins {
id 'com.android.application'
id 'kotlin-android'
id 'kotlin-kapt'
}
android {
compileSdk 31
defaultConfig {
applicationId "com.example.mynotes"
minSdk 27
targetSdk 31
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
packagingOptions {
exclude 'META-INF/atomicfu.kotlin_module'
}
}
dependencies {
implementation "androidx.appcompat:appcompat:$rootProject.appCompatVersion"
implementation "androidx.activity:activity-ktx:$rootProject.activityVersion"
// Dependencies for working with Architecture components
// You'll probably have to update the version numbers in build.gradle (Project)
// Room components
implementation "androidx.room:room-ktx:$rootProject.roomVersion"
kapt "androidx.room:room-compiler:$rootProject.roomVersion"
androidTestImplementation "androidx.room:room-testing:$rootProject.roomVersion"
// Lifecycle components
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$rootProject.lifecycleVersion"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:$rootProject.lifecycleVersion"
implementation "androidx.lifecycle:lifecycle-common-java8:$rootProject.lifecycleVersion"
// Kotlin components
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$rootProject.coroutines"
api "org.jetbrains.kotlinx:kotlinx-coroutines-android:$rootProject.coroutines"
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.0'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.0'
// UI
implementation "androidx.constraintlayout:constraintlayout:$rootProject.constraintLayoutVersion"
implementation "com.google.android.material:material:$rootProject.materialVersion"
// Testing
testImplementation "junit:junit:$rootProject.junitVersion"
androidTestImplementation "androidx.arch.core:core-testing:$rootProject.coreTestingVersion"
androidTestImplementation ("androidx.test.espresso:espresso-core:$rootProject.espressoVersion", {
exclude group: 'com.android.support', module: 'support-annotations'
})
androidTestImplementation "androidx.test.ext:junit:$rootProject.androidxJunitVersion"
}
和ViewModel.kt
package com.example.mynotes
import android.app.Application
//import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.LiveData
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.*
class NotesViewModel(application: Application) : ViewModel() {
private val repository : NotesRepository
val allNotes : LiveData<List<Notes>>
init {
val dao = NotesDatabase.getDatabase(application).getNotesDao()
repository = NotesRepository(dao)
allNotes = repository.allNotes
}
fun deleteNotes(notes: Notes) = viewModelScope.launch(Dispatchers.IO) {
repository.delete(notes)
}
}
在 deleteNotes 函数中“viewModelScope.launch”显示未解决的引用:启动但在构建应用程序时没有错误,但我的应用程序在 运行.
时崩溃我认为这是因为您声明变量的方式,因为您将其声明为直接函数,您可以尝试以下操作:
fun deleteNotes(notes: Notes) {
viewModelScope.launch(Dispatchers.IO) {
repository.delete(notes)
}
}
问题可能与方法声明并存储在内存中时,作用域还没有分配有关。
您使用的是哪个版本?
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.3.1"
尝试使用这种情况是不同的。
如果仍然无法识别,请尝试使缓存无效并重新启动