我是 flutter 的新手，我构建了一个非常小的应用程序来显示当前的纬度和经度，这需要我在 pubspec.yaml 中添加两个依赖项:-

location 和 simple_permissions 获取当前用户位置并请求位置权限。

但是当我运行该应用程序时，它显示以下错误:-

Gradle task 'assembleDebug'...
D8: Program type already present: android.support.v4.media.MediaBrowserCompat$CustomActionCallback

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/2.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/3.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/4.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/5.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/6.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/7.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/8.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/9.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/10.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/11.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/12.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/13.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/14.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/15.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/16.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/17.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/18.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/19.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/20.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/21.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/22.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/23.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/24.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/25.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/26.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/27.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/28.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/29.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/30.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/31.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/32.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/33.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/34.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/35.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/36.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/37.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/38.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/39.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/40.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/41.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/42.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/43.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/44.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/45.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/46.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/47.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/48.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/49.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/50.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/51.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/52.jar, /home/letsdoit/IdeaProjects/location/build/app/intermediates/transforms/dexBuilder/debug/53.jar
  Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
  Program type already present: android.support.v4.media.MediaBrowserCompat$CustomActionCallback

* 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 9s
Finished with error: Gradle task assembleDebug failed with exit code 1

我认为这是因为添加了两次库，但我没有手动添加依赖项，因此内部出现 flutter 错误。

请告诉我解决方法

./gradlew app:dependecies 的输出如下:-

+--- project :location
|    \--- com.google.android.gms:play-services-location:15.+ -> 15.0.1
|         +--- com.google.android.gms:play-services-base:[15.0.1,16.0.0) -> 15.0.1
|         |    +--- com.google.android.gms:play-services-basement:[15.0.1] -> 15.0.1
|         |    |    \--- com.android.support:support-v4:26.1.0 -> 27.1.1
|         |    |         +--- com.android.support:support-compat:27.1.1
|         |    |         |    +--- com.android.support:support-annotations:27.1.1
|         |    |         |    \--- android.arch.lifecycle:runtime:1.1.0
|         |    |         |         +--- android.arch.lifecycle:common:1.1.0
|         |    |         |         \--- android.arch.core:common:1.1.0
|         |    |         +--- com.android.support:support-media-compat:27.1.1
|         |    |         |    +--- com.android.support:support-annotations:27.1.1
|         |    |         |    \--- com.android.support:support-compat:27.1.1 (*)
|         |    |         +--- com.android.support:support-core-utils:27.1.1
|         |    |         |    +--- com.android.support:support-annotations:27.1.1
|         |    |         |    \--- com.android.support:support-compat:27.1.1 (*)
|         |    |         +--- com.android.support:support-core-ui:27.1.1
|         |    |         |    +--- com.android.support:support-annotations:27.1.1
|         |    |         |    +--- com.android.support:support-compat:27.1.1 (*)
|         |    |         |    \--- com.android.support:support-core-utils:27.1.1 (*)
|         |    |         \--- com.android.support:support-fragment:27.1.1
|         |    |              +--- com.android.support:support-compat:27.1.1 (*)
|         |    |              +--- com.android.support:support-core-ui:27.1.1 (*)
|         |    |              +--- com.android.support:support-core-utils:27.1.1 (*)
|         |    |              +--- com.android.support:support-annotations:27.1.1
|         |    |              +--- android.arch.lifecycle:livedata-core:1.1.0
|         |    |              |    +--- android.arch.lifecycle:common:1.1.0
|         |    |              |    +--- android.arch.core:common:1.1.0
|         |    |              |    \--- android.arch.core:runtime:1.1.0
|         |    |              |         \--- android.arch.core:common:1.1.0
|         |    |              \--- android.arch.lifecycle:viewmodel:1.1.0
|         |    \--- com.google.android.gms:play-services-tasks:[15.0.1] -> 15.0.1
|         |         \--- com.google.android.gms:play-services-basement:[15.0.1] -> 15.0.1 (*)
|         +--- com.google.android.gms:play-services-basement:[15.0.1,16.0.0) -> 15.0.1 (*)
|         +--- com.google.android.gms:play-services-places-placereport:[15.0.1,16.0.0) -> 15.0.1
|         |    \--- com.google.android.gms:play-services-basement:[15.0.1,16.0.0) -> 15.0.1 (*)
|         \--- com.google.android.gms:play-services-tasks:[15.0.1,16.0.0) -> 15.0.1 (*)
+--- project :simple_permissions
|    \--- com.android.support:support-v4:27.1.1 (*)
\--- org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71
     \--- org.jetbrains.kotlin:kotlin-stdlib:1.2.71
          +--- org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71
          \--- org.jetbrains:annotations:13.0

我的应用程序的 build.gradle 如下:-

//noinspection GradleCompatible
def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 28
    buildToolsVersion "28.0.3"

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "ab"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation "com.android.support:multidex:1.0.3"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

pubspec.yaml :-

name: a
description: b

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
  sdk: ">=2.0.0-dev.68.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  permission_handler: ^2.2.0
  location: ^2.0.0



  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2

dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.io/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.io/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.io/custom-fonts/#from-packages

最佳答案

这个 gradle 错误消息很难解决...好吧，我遇到了一些这样的问题，我写下了我是如何解决的 here .不管怎样，我建议你在你的 pubspec 中使用更新的包。 simple_permissions包已经有一段时间没有更新了，试试permission_handler包代替。避免 future 构建问题的另一点是将您的应用程序迁移到 androidX 并使用已经使用 androidX 的依赖项，许多官方插件正在迁移到它，当我们在同一个项目中将支持库与 androidX 混合时，构建过程会遗憾地失败。如果您计划在您的应用中包含 google_maps，我真的建议您迁移到 androidX 而不是避免它。

AndroidX 是原始的支持库包和其他命名空间的类。完整说明 here .

您可以手动迁移到 androidx，也可以使用有时会失败的 android-studio 迁移工具。已经描述了使用 android-studio 工具的迁移过程 here详细信息。

要手动迁移，您需要将所有支持库依赖项替换为相应的 androidx 包。一个例子是:

dependencies {
   // using support library
   implementation 'com.android.support:appcompat-v7:$version' 
}

必须替换为

dependencies {
       // using androidx
       implementation 'androidx.appcompat:appcompat:$version' //androidx artifact 
    }

可以找到 Androidx Artifact 映射 here 在你的 gradle.properties 文件中，你需要在下面插入这两行

android.enableJetifier=true
android.useAndroidX=true

并确保你的 flutter 依赖项也在使用 androix。

看看this flutter page 它讨论了 androidX 兼容性和迁移。

希望对你有帮助。

关于android - D8 : Program type already present: android. support.v4.media.MediaBrowserCompat$CustomActionCallback，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54771498/