flutter运行app失败 running gradle task assembleDebug

flutter环境搭建完成之后，创建好了项目，在运行项目flutter run，就一直卡在那，就像这样：

运行时会卡在Running Gradle task 'assembleDebug'..., 之后就会报这样的错

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'.
> Could not resolve all task dependencies for configuration ':app:debugCompileClasspath'.
   > Could not resolve io.flutter:flutter_embedding_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
     Required by:
         project :app
      > Could not resolve io.flutter:flutter_embedding_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.  
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.        
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/172.217.27.144] failed: Connection timed out: connect
      > Could not resolve io.flutter:flutter_embedding_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.       
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.  
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.        
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.80] failed: Connection timed out: connect
      > Could not resolve io.flutter:flutter_embedding_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.  
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/flutter_embedding_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/flutter_embedding_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.        
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.80] failed: Connection timed out: connect
   > Could not resolve io.flutter:x86_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
     Required by:
         project :app
      > Could not resolve io.flutter:x86_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/172.217.27.144] failed: Connection timed out: connect
      > Could not resolve io.flutter:x86_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.80] failed: Connection timed out: connect
      > Could not resolve io.flutter:x86_debug:1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.
         > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
            > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32/x86_debug-1.0.0-6bc433c6b6b5b98dcf4cc11aff31cdee90849f32.pom'.
               > Connect to storage.googleapis.com:443 [storage.googleapis.com/34.64.4.80] failed: Connection timed out: connect

* 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 7m 50s
Running Gradle task 'assembleDebug'...
Running Gradle task 'assembleDebug'... Done                       472.2s (!)
Exception: Gradle task assembleDebug failed with exit code 1

这是因为Gradle的Maven仓库在国外, 可以使用阿里云的镜像地址。

解决方法：

1.修改项目中android/build.gradle文件

buildscript {
    ext.kotlin_version = '1.3.50'
    repositories {
        // 修改
        // google()
        // jcenter()
        maven { url 'https://maven.aliyun.com/repository/google' }
        maven { url 'https://maven.aliyun.com/repository/jcenter' }
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }

    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        // 修改
        // google()
        // jcenter()
        maven { url 'https://maven.aliyun.com/repository/google' }
        maven { url 'https://maven.aliyun.com/repository/jcenter' }
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }
    }
}

2. 修改flutter sdk安装目录下的 packages/flutter_tools/gradle/flutter.gradle

buildscript {
    repositories {
        // 修改
        // google()
        // jcenter()
		maven { url 'https://maven.aliyun.com/repository/google' }
        maven { url 'https://maven.aliyun.com/repository/jcenter' }
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
    }
}

    // 修改
    // private static final String MAVEN_REPO      = "https://storage.googleapis.com/download.flutter.io";
    private static final String MAVEN_REPO      = "https://storage.flutter-io.cn/download.flutter.io";

3. 重新运行 flutter run