flutter run 报错

Question

/C:/Users/win%2010/AppData/Roaming/Pub/Cache/hosted/pub.flutter-io.cn/flutter_datetime_picker-1.3.8/lib/src/datetime_picker_theme.dart:6:28: Error: Type 'DiagnosticableMixin' not found.
class DatePickerTheme with DiagnosticableMixin {
                       ^^^^^^^^^^^^^^^^^^^
/C:/Users/win%2010/AppData/Roaming/Pub/Cache/hosted/pub.flutter-io.cn/flutter_datetime_picker-1.3.8/lib/src/datetime_picker_theme.dart:6:7: Error: The type 'DiagnosticableMixin' can't be mixed in.
class DatePickerTheme with DiagnosticableMixin {
  ^


FAILURE: Build failed with an exception.

* Where:
Script 'D:\weex\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 899

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command 'D:\weex\flutter\bin\flutter.bat'' finished with non-zero exit value 1

* 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 42s
Exception: Gradle task assembleDebug failed with exit code 1

Answer 1

你的 flutter 是 1.20.0+ 吧。DiagnosticableMixin 被移除了。
所以你引用的 package 无法编译。

解决方案：

1. 使用 flutter 的 stable 版本。
2. fork 那个 package ，将 DiagnosticableMixin 替换为 Diagnosticable。
3. 临时使用我的 fork

Answer 2

flutter_datetime_picker 依赖 flutter的 DiagnosticableMixi方法 ，但是最新版的flutter 已经移除了DiagnosticableMixi方法

1、dev 版本的截止目前还可以正常使用 ，flutter channel dev试试
2、或者去 flutter_datetime_picker 看看版本升级的问题有没有解决 如果解决了，升级flutter_datetime_picker到最新版

Answer 3

我也出现这问题了