我的ViewModel遇到以下错误:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.cryptpass_kt/com.example.cryptpass_kt.MainActivity}: java.lang.RuntimeException: Cannot create an instance of class com.example.cryptpass_kt.EntryViewModel
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2853)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2928)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1609)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6703)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)
Caused by: java.lang.RuntimeException: Cannot create an instance of class com.example.cryptpass_kt.EntryViewModel
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:238)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:164)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:130)
at com.example.cryptpass_kt.MainActivity.onCreate(MainActivity.kt:40)
at android.app.Activity.performCreate(Activity.java:6980)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2806)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2928)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1609)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6703)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:334)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:230)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:164)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:130)
at com.example.cryptpass_kt.MainActivity.onCreate(MainActivity.kt:40)
at android.app.Activity.performCreate(Activity.java:6980)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2806)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2928)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1609)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6703)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)
Caused by: kotlin.UninitializedPropertyAccessException: lateinit property allEntries has not been initialized
at com.example.cryptpass_kt.EntryRepository.getAllEntries(EntryRepository.kt:9)
at com.example.cryptpass_kt.EntryViewModel.<init>(EntryViewModel.kt:11)
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:334)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:230)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:164)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:130)
at com.example.cryptpass_kt.MainActivity.onCreate(MainActivity.kt:40)
at android.app.Activity.performCreate(Activity.java:6980)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2806)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2928)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1609)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6703)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:769)
错误指向我的应用中的3个位置。第一个是我的
viewModel
类的MainActivity.kt
方法中onCreate()
对象的初始化:override fun onCreate(savedInstanceState: Bundle?) {
...
viewModel = ViewModelProviders.of(this).get(EntryViewModel::class.java)
viewModel.allEntries.observe(this, Observer { entries -> adapter.submitList(entries) })
...
}
第二点是我的存储库类中的
LiveData
对象:class EntryRepository(application: Application) {
private val entryDAO: EntryDAO
lateinit var allEntries: LiveData<List<Entry>>
...
}
第三点是
ViewModel
内的存储库对象:class EntryViewModel(application: Application) : AndroidViewModel(application) {
private val repository: EntryRepository = EntryRepository(application)
val allEntries: LiveData<List<Entry>>
init {allEntries = repository.allEntries }
fun insert(entry: Entry) {repository.insert(entry)}
fun update(entry: Entry) {repository.update(entry)}
fun delete(entry: Entry) {repository.update(entry)}
fun deleteAll() {repository.deleteAllEntries()}
}
我第一次遇到此错误时,在S/O上被告知,这是由于我的gradle文件中有一些与AnroidX不兼容的实现。解决此问题后,问题仍然存在。
最佳答案
Caused by: kotlin.UninitializedPropertyAccessException: lateinit property allEntries has not been initialized
在
EntryViewModel
中,您具有以下这一行:init {allEntries = repository.allEntries }
您正在引用
allEntries
的EntryRepository
属性。定义为lateinit
:lateinit var allEntries: LiveData<List<Entry>>
该错误告诉您在尝试引用
allEntries
之前尚未为其分配值。如果要在可见(非lateinit
)属性上使用private
,则需要确保在为其他对象尝试使用该属性之前为其分配值。