突然我开始得到这个错误,我不知道为什么如果有人告诉我这个错误在哪里,就足够有帮助了。正如我所能得到的,这是因为android studio的新更新。 我得到的错误的详细总结。

Task :app:kaptDebugKotlin
    ANTLR Tool version 4.5.3 used for code generation does not match the current runtime version 4.7.1ANTLR Runtime version 4.5.3 used for parser compilation does not match the current runtime version 4.7.1ANTLR Tool version 4.5.3 used for code generation does not match the current runtime version 4.7.1ANTLR Runtime version 4.5.3 used for parser compilation does not match the current runtime version 4.7.1C:\Users\shubh\Downloads\MarginCalculator\app\build\generated\source\kapt\debug\com\kotlin_developer\margincalculator\DataBinderMapperImpl.java:10: error: cannot find symbol
    import com.kotlin_developer.margincalculator.databinding.FragmentCalculatorScreenBindingImpl;

    symbol:   class FragmentCalculatorScreenBindingImpl

    Task :app:kaptDebugKotlin FAILED
    location: package com.kotlin_developer.margincalculator.databinding
    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

BUILD FAILED in 17s
29 actionable tasks: 27 executed, 2 up-to-date

当前回答

在我的情况下,我忘记在实体类中添加@PrimaryKey。

其他回答

在我的例子中,当我从jcenter()移动到mavenCentral()时,我得到了这个错误,我的一个依赖只在jcenter()上可用,而不是mavenCentral()。 所以我向github上的所有者提交了同样的问题,并将等待删除jcenter(),直到它被移动。

在我的例子中,这是因为我没有在我的ViewModel中实现Observable。我添加了一个EditText约束布局与android:text="@={addProductViewModel.inputProductName}"

一旦我在ViewModel类中实现了Observable,错误就消失了

ViewModel

class AddProductViewModel (
    private val repository: ProductRepository,
    private val context: Context
): ViewModel(), Observable {

    @Bindable
    val inputProductName = MutableLiveData<String>()


    fun addProduct() {
        //inputProductName.value
    }

    override fun removeOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
        TODO("Not yet implemented")
    }

    override fun addOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
        TODO("Not yet implemented")
    }
}

使用片段的MVVM数据绑定的完整示例

布局- add_product.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android" >
    <data class=".AddProductBinding">
        <variable
            name="addProductViewModel"
            type="com.rao.iremind.AddProductViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">


        <EditText
            android:id="@+id/editTextTextProductName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ems="10"
            android:hint="Product name"
            android:inputType="textPersonName"
            android:text="@={addProductViewModel.inputProductName}"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />



    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

AddProductFragment

class AddProductFragment: Fragment() {
    private lateinit var binding: AddProductBinding
    private lateinit var addProductViewModel: AddProductViewModel
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        binding =  DataBindingUtil.inflate(inflater, R.layout.add_product, container, false)
        val dao = SubscriberDatabase.getInstance(requireActivity().applicationContext).productDAO
        val repository = ProductRepository(dao)
        val factory = AddProductViewModelFactory(repository, requireActivity().applicationContext)
        addProductViewModel = ViewModelProvider(this, factory).get(AddProductViewModel::class.java)
        binding.addProductViewModel = addProductViewModel
        binding.lifecycleOwner = this
        val view = binding.root

        return view
    }
}

添加产品视图模型

class AddProductViewModel (
    private val repository: ProductRepository,
    private val context: Context
): ViewModel(), Observable {

    @Bindable
    val inputProductName = MutableLiveData<String>()


    fun addProduct() {
        //inputProductName.value
    }

    override fun removeOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
        TODO("Not yet implemented")
    }

    override fun addOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
        TODO("Not yet implemented")
    }
}

希望这能有所帮助 R

在我的案例中,降低kotlin版本(从1.4.21到1.3.21)解决了我的问题。

    buildscript { 
    ext.kotlin_version = '1.3.21'

    repositories {
        google()
        jcenter()
        
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.1'
        
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" }
}

有趣的是,我得到这个错误是因为我添加了Retrofit的描述。注意不要混淆“房间”和“改造”的描述。

大声喊出上面@Rene Spies的回答,我在使用数据绑定时也得到了这个错误。当您将@Bindable注释放在Kotlin中数据类的主构造函数的字段上时,构建引擎不喜欢这样做。

所以不要做下面的事情,

data class MyAwesomePojo(
    @Bindable
    var firstname: String,
    var lastname: String
)

相反,你需要做的是

data class MyCorrectAwesomePojo(
    var lastname: String
):{
    @get:Bindable
    var firstname: String
        set(value){
            field = value
        }
}

好处:如果你像我一样试图使用双向绑定来防止设置和获取的无限循环,请记得在设置值到字段之前检查相同的值。