Flutter 1.17 代理问题

Flutter Sdk 1.17版本更新后，运行项目，出现代理问题，如果不“翻墙”，部分Jar包下载不了。以下有两种方式可以解决，亲测！

如果仍未解决或者有更好的解决方式，可以评论留言。

问题描述：

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugDuplicateClasses'.
> Could not resolve all files for configuration ':app:debugRuntimeClasspath'.
   > Could not download arm64_v8a_debug.jar (io.flutter:arm64_v8a_debug:1.0.0-540786dd51f112885a89792d678296b95e6622e5)
      > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/arm64_v8a_debug/1.0.0-540786dd51f112885a89792d678296b95e6622e5/arm64_v8a_debug-1.0.0-540786dd51f112885a89792d678296b95e6622e5.jar'.
         > Could not HEAD 'https://storage.googleapis.com/download.flutter.io/io/flutter/arm64_v8a_debug/1.0.0-540786dd51f112885a89792d678296b95e6622e5/arm64_v8a_debug-1.0.0-540786dd51f112885a89792d678296b95e6622e5.jar'.
            > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.112] failed: Connection timed out: connect
   > Could not download x86_64_debug.jar (io.flutter:x86_64_debug:1.0.0-540786dd51f112885a89792d678296b95e6622e5)
      > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-540786dd51f112885a89792d678296b95e6622e5/x86_64_debug-1.0.0-540786dd51f112885a89792d678296b95e6622e5.jar'.
         > Could not HEAD 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-540786dd51f112885a89792d678296b95e6622e5/x86_64_debug-1.0.0-540786dd51f112885a89792d678296b95e6622e5.jar'.
            > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.112] failed: Connection timed out: connect

第一种：在工程.android目录中，对应的build.gradle文件下，添加代码后重新编译，如下

allprojects {
    repositories {
        google()
        jcenter()
        maven { url "http://download.flutter.io" }
    }
}

第二种：修改flutter sdk中flutter/packages/flutter_tools/gradle/文件夹下三个文件，如下：

修改：flutter/packages/flutter_tools/gradle/resolve_dependencies.gradle

flutter/packages/flutter_tools/gradle/aar_init_script.gradle

flutter/packages/flutter_tools/gradle/flutter.gradle

中的：https://storage.googleapis.com/download.flutter.io   替换为：http://download.flutter.io   重新编译就好了