数据绑定：变量名 "unresolved reference"

Question

我无法将 databinding 用于 activity。（我用 databinding 代替 fragment/recyclerview）。

我研究了所有文档和所有问题，但没有解决我的问题。

我的问题是 xml 文件中变量名称的“未解析引用”。我的项目哪里出了问题。

DetailActivity.kt

class DetailActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val activityMainBinding: ActivityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_detail)
        val model: Result = intent.getSerializableExtra("movieModel") as Result
        activityMainBinding.setResult = model
    }
}

activity_detail.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="result"
            type="com.bahadirerdem.moviescatalog.model.responseModel.Result" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".view.activity.DetailActivity" >

        <androidx.constraintlayout.widget.Guideline
            android:id="@+id/guideline4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            app:layout_constraintGuide_percent="0.32" />

        <ImageView
            android:id="@+id/movie_banner"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:scaleType="centerCrop"
            android:downloadUrl="@{result.backdrop_path}"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            tools:src="@tools:sample/backgrounds/scenic" />

        <TextView
            android:id="@+id/movie_desc_textview"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginEnd="8dp"
            android:scrollbars="vertical"
            android:text="@{result.overview}"
            app:layout_constraintBottom_toTopOf="@+id/bottom_constraint"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/guideline4" />

        <TextView
            android:id="@+id/movie_title_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginBottom="8dp"
            android:text="@{result.title}"
            app:layout_constraintBottom_toTopOf="@+id/rating_textview"
            app:layout_constraintStart_toStartOf="parent" />

        <TextView
            android:id="@+id/rating_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginBottom="4dp"
            android:gravity="center_horizontal"
            android:text="@{result.vote_count}"
            app:drawableLeftCompat="@drawable/ic_favorite"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintStart_toStartOf="parent" />

        <TextView
            android:id="@+id/date_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:layout_marginBottom="4dp"
            android:text="@{result.release_date}"
            android:textColor="@color/white"
            app:drawableRightCompat="@drawable/ic_watchlist"
            app:layout_constraintBottom_toTopOf="@+id/guideline4"
            app:layout_constraintEnd_toEndOf="parent" />

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/bottom_constraint"
            android:layout_width="0dp"
            android:layout_height="56dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent">

            <ImageView
                android:id="@+id/imageView2"
                android:layout_width="32dp"
                android:layout_height="32dp"
                android:layout_marginStart="8dp"
                android:src="@drawable/ic_favorite"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintStart_toEndOf="@+id/imageView3"
                app:layout_constraintTop_toTopOf="parent" />

            <ImageView
                android:id="@+id/imageView3"
                android:layout_width="32dp"
                android:layout_height="32dp"
                android:src="@drawable/ic_watchlist"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

build.gradle（应用程序）

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'kotlin-android-extensions'
    id 'androidx.navigation.safeargs.kotlin'
    id 'kotlin-kapt'
}
android {
    compileSdkVersion 29
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "com.bahadirerdem.moviescatalog"
        minSdkVersion 19
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        multiDexEnabled true

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    dataBinding{
        enabled = true
    }

    kapt {
        generateStubs = true
    }

    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'
    }
}

dependencies {
    def lifeCycleExtensionVersion = '1.1.1'
    def retrofitVersion = '2.3.0'
    def glideVersion = '4.11.0'
    def rxJavaVersion = '2.1.1'

    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'com.android.support:multidex:1.0.3'

    implementation 'androidx.navigation:navigation-fragment-ktx:2.3.4'
    implementation 'androidx.navigation:navigation-ui-ktx:2.3.4'

    implementation "com.squareup.retrofit2:retrofit:$retrofitVersion"
    implementation "com.squareup.retrofit2:converter-gson:$retrofitVersion"
    implementation "com.squareup.retrofit2:adapter-rxjava2:$retrofitVersion"

    implementation "io.reactivex.rxjava2:rxjava:$rxJavaVersion"
    implementation "io.reactivex.rxjava2:rxandroid:$rxJavaVersion"

    implementation "com.github.bumptech.glide:glide:$glideVersion"

    implementation "android.arch.lifecycle:extensions:$lifeCycleExtensionVersion"
    
    kapt "com.android.databinding:compiler:3.1.4"

    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

我试过清理项目、重建项目、使缓存无效并重新启动但不能解决我的问题我哪里做错了？帮帮我...

Answer 1

问题是您引用了 MainActivity 的绑定 class，即 (ActivityMainBinding) 到 DetailActivity。

因此，它在ActivityMainBinding中找不到setResult()方法，因为activity_main.xml布局中没有result变量。

请注意，每个 activity 都有一个唯一生成的 class，绑定到它自己的布局。

要解决此问题，您需要将 ActivityMainBinding 替换为 ActivityDetailBinding

class DetailActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val activityDetailBinding: ActivityDetailBinding = DataBindingUtil.setContentView(this, R.layout.activity_detail)
        val model: Result = intent.getSerializableExtra("movieModel") as Result
        activityDetailBinding.setResult = model
    }
}

数据绑定：变量名 "unresolved reference"

Databinding: "unresolved reference" for variable name

android

android-layout

kotlin

android-databinding