顫動：添加“image_cropper”和“contacts_service”包時構建錯誤

Question

我可以成功構建並運行一個全新的撲動項目。 但是，當我將image_cropper: ^1.0.0和contacts_service: ^0.2.4包添加到pubspec.yaml並運行flutter packages get ，我無法再構建項目，並得到此構建錯誤：

D8: Program type already present: android.support.v4.app.INotificationSideChannel

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: E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\2.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\3.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\4.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\5.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\6.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\7.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\8.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\9.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\10.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\11.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\12.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\13.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\14.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\15.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\16.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\17.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\18.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\19.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\20.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\21.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\22.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\23.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\24.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\25.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\26.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\27.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\28.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\29.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\30.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\31.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\32.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\33.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\34.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\35.jar, E:\Projects\flutter\hello\build\app\intermediates\transforms\dexBuilder\debug\36.jar
  Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
  Program type already present: android.support.v4.app.INotificationSideChannel

* 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 1m 19s
*******************************************************************************************
The Gradle failure may have been because of AndroidX incompatibilities in this Flutter app.
See https:///CP92wY for more information on the problem and how to fix it.
*******************************************************************************************
Finished with error: Gradle task assembleDebug failed with exit code 1

我不太了解這個錯誤，但似乎這兩個包之間存在命名沖突（因為錯誤文本中有duplicate_classes ）。 這有什么解決方法嗎？

請注意，對於我來說任何其他包都不會發生此錯誤。

Answer 1

在build.gradle中，defaultConfig添加multiDexEnabled true

Answer 2

這是Android X兼容性問題。 我可以按照這里提到的步驟修復它，但總結如下：

1. 首先確保app / build.gradle中的compileSdkVersion至少為28。 此屬性控制Gradle用於構建APK的Android SDK版本。 它不會影響您的應用可以運行的最低SDK版本。
2. 右鍵單擊flutter項目的android目錄並使用此菜單打開它： Flutter > Open android module in android studio
3. 在新打開的項目中，從菜單中選擇Refactor > Migrate to AdnroidX
4. 關閉項目並再次打開flutter項目。