微信沒有提供官方的Flutter插件，所以找了個比較多人用的微信插件：fluwx，項目只需要微信授權(quán)登錄，還有其他功能大家可以試試。

首先需要在 微信開放平臺 注冊成為開發(fā)者并創(chuàng)建應(yīng)用，審核通過后得到AppId。

引入

在pubspec.yaml里添加：

dependencies:
  fluwx: ^1.0.4

添加完成后 flutter pub get

初始化

import 'package:fluwx/fluwx.dart' as fluwx;

fluwx.register(appId:"wxd930ea5d5a258f4f");
fluwx.sendAuth(scope: "snsapi_userinfo", state: "wechat_sdk_demo_test")；

fluwx.responseFromAuth.listen((response) {
  //監(jiān)聽授權(quán)登錄回調(diào)
  print("code: " + response.code);
});

• appId：微信開放平臺申請的appid
• scope ：為固定值
• state ：任意自定義字符串

獲取code后可以傳給后臺獲取access_token。

遇到的問題

fluwx 用到 kotlin 和 Luban，編譯的時候遇到一些問題：

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'android'.
> Could not resolve all artifacts for configuration ':classpath'.
   > Could not download kotlin-compiler-embeddable.jar (org.jetbrains.kotlin:kotlin-compiler-embeddable:1.3.40)
      > Could not get resource 'https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-compiler-embeddable/1.3.40/kotlin-compiler-embeddable-1.3.40.jar'.
         > Could not GET 'https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-compiler-embeddable/1.3.40/kotlin-compiler-embeddable-1.3.40.jar'.
            > Read timed out

* 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

• kotlin-compiler-embeddable-1.3.40.jar 一直下載不成功，最后還是手動下載，復(fù)制到./gradle/caches/modules-2/file-2.1/org.jetbrains.kotlin/kotlin-compiler-embeddable/1.3.40(版本號)/29418ab24831ca819005f20aa32862c26938f284(AS生成的)目錄下，重啟AS，就可以了。

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:preDebugBuild'.
> Could not resolve all dependencies for configuration ':app:debugRuntimeClasspath'.
   > Could not determine artifacts for top.zibin:Luban:1.1.8
      > Could not get resource 'https://jcenter.bintray.com/top/zibin/Luban/1.1.8/Luban-1.1.8.aar'.
         > Could not HEAD 'https://jcenter.bintray.com/top/zibin/Luban/1.1.8/Luban-1.1.8.aar'.
            > Read timed out

* 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 3s
Finished with error: Gradle task assembleDebug failed with exit code 1

• Luban-1.1.8.aar 也是一直下載失敗，本來想著跟上面同樣的方法處理，后面發(fā)現(xiàn)不行，會出現(xiàn)重復(fù)類錯誤：

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: 項目目錄/build/app/intermediates/transforms/dexBuilder/debug/xx.jar, 
  Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
  Program type already present: top.zibin.luban.BuildConfig

* 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 58s
Finished with error: Gradle task assembleDebug failed with exit code 1

刪除后重新編譯就下載成功了 - - ！。

• 微信授權(quán)登錄包名和簽名要跟開放平臺注冊的一致，為了方便調(diào)試，把AS默認的 debug 簽名改成注冊時的簽名，在app/build.gradle 里設(shè)置簽名配置：

android {
    ...
    signingConfigs {//簽名配置
        release {//發(fā)布版簽名配置
            storeFile file("your.jks")//密鑰文件路徑
            storePassword "psw"http://密鑰文件密碼
            keyAlias "alias"http://key別名
            keyPassword "psw"http://key密碼
        }
        debug {//debug版簽名配置
            storeFile file("your.jks")
            storePassword "psw"
            keyAlias "alias"
            keyPassword "psw"
        }
    }
    ...
}

然后就可以直接編譯，調(diào)起微信登錄了。