带有数据绑定错误的 androidx：包 android.support.constraint 不存在

Question

我刚刚了解databinding 并尝试使用新的库结构作为androidx。 当我尝试构建项目时，我遇到了这个错误。

错误：包 android.support.constraint 不存在

这个错误在Binding生成的文件中为

public class ActivityMainBindingImpl extends ActivityMainBinding  {
    @Nullable
    private static final androidx.databinding.ViewDataBinding.IncludedLayouts sIncludes;
    @Nullable
    private static final android.util.SparseIntArray sViewsWithIds;
    static {
        sIncludes = null;
        sViewsWithIds = null;
    }
    // views
    @NonNull
    private final android.support.constraint.ConstraintLayout mboundView0;
    @NonNull
    private final android.widget.TextView mboundView1;

这是我的build.gradle 应用模块。

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.climesoft.learn.livedatabinding"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    dataBinding {
        enabled = true
    }
}


dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
}

这里是build.gradle 项目模块。

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext.kotlin_version = '1.3.10'
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.2.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

最后的gradle.properties文件是这个。

# Project-wide Gradle settings.
# IDE (e.g. Android Studio) users:
# Gradle settings configured through the IDE *will override*
# any settings specified in this file.
# For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
org.gradle.jvmargs=-Xmx1536m
# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
# org.gradle.parallel=true
# Kotlin code style for this project: "official" or "obsolete":
kotlin.code.style=official

android.useAndroidX=true

android.enableJetifier=true

那么为什么android studio 不使用androidx.constraintlayout 包生成Binding 类呢？

Answer 1

如果你使用

com.heinrichreimersoftware:material-intro:x.x.x

尝试改变：

implementation 'com.heinrichreimersoftware:material-intro:master-SNAPSHOT'

Answer 2

使用 androidx，包名称已更改。原来的 android.support 现在是 androidx。通常，当您将项目转换为 androidx/jetpack 时，AndroidStudio 会自动更改。在某处的 Build... 菜单中有一个选项。

Answer 3

android.support.constraint 表示您使用的是支持库而不是 AndroidX。

您可能应该将activity_main.xml 中的android.support.constraint.ConstraintLayout 更改为androidx.constraintlayout.widget.ConstraintLayout。