你必须在gradle模块中添加buildFeatures

android {
    buildFeatures{
        dataBinding true
    }
}

例子:

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 30

    defaultConfig {
        applicationId "com.demo"
        minSdkVersion 21
        targetSdkVersion 30
        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
    }

    buildFeatures{
        dataBinding true
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation 'org.jetbrains:annotations:15.0'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

从Android Gradle Plugin 4.0.0-alpha05开始，有一个名为buildFeatures的新块来启用构建功能。

因此，为了使数据绑定与新的AGP插件，你必须在模块(例如:app)级别的gradle文件

构建。gradle (Groovy DSL)

// shorter version
// android.buildFeatures.dataBinding true


// longer version

android {

    buildFeatures {

         dataBinding true

         // for view binding:
         // viewBinding true
    }
}

build.gradle.kts （ Kotlin DSL ）

// shorter version
// android.buildFeatures.dataBinding = true


// longer version

android {

  buildFeatures {

         dataBinding = true

         // for view binding:
         // viewBinding = true
    }
}

参考:https://developer.android.com/studio/releases/gradle-plugin # buildFeatures

以下工作:

android { compileSdkVersion 30 buildToolsVersion“30.0.3”

defaultConfig {
    applicationId "com.poet.navviewmodeljave"
    minSdkVersion 19
    targetSdkVersion 30
    versionCode 1
    versionName "1.0"
    //dataBinding.enabled true
    buildFeatures.dataBinding
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}

出现此警告是因为

    dataBinding {
        enabled=true
    }

    viewBinding {
        enabled=true
    }

这种代码风格已弃用，并将从gradle版本5中删除 现在如果你仍然想使用这个，那么你可以使用androidx遗留的支持依赖项

在应用程序级别build.gradle

implementation 'androidx.legacy:legacy-support-v4:1.0.0'

否则，您可以使用新的代码样式来启用数据绑定和视图绑定

像这样

android {

  buildFeatures {

         dataBinding = true

         // for view binding:
         // viewBinding = true
    }
}

buildFeatures {

        //just for dataBinding ，It has nothing to do with viewBinding 
        dataBinding = true

        //just for viewBinding ，It has nothing to do with dataBinding
        viewBinding = true
    }

看看上面的注释，应该很清楚了

如果您正在寻找新的特性viewBinding，可以试试Groovy的这个特性

android {
    ...
    buildFeatures {
        viewBinding true
    }
}

这是给Kotlin的

android {
    ...
    buildFeatures {
        viewBinding true
    }
}

但是，要使用默认的android数据绑定

android {
    ...
    buildFeatures {
        dataBinding true
    }
}

另外，要注意使用

kapt "com.android.databinding:compiler:4.0.0"