[移动开发]Android studio 2020.3.1 编译Flutter报错：Unexpected lock protocol found in lock file. Expected 3 found 0

1.Android studio 2020.3.1 编译Flutter报错：

? Unexpected lock protocol found in lock file. Expected 3, found 0.

2.解决Flutter编译一直显示 Running Gradle task 'assembleDebug'

1.修改 Flutter SDK 文件，位置：C:\flutter\packages\flutter_tools\gradle\flutter.gradle

// Code ......

buildscript {
    repositories {
        //google()  // 注释掉
        //mavenCentral()  // 注释掉

        /* 参考仓库地址：https://developer.aliyun.com/mvn/guide */
        maven { url 'https://maven.aliyun.com/repository/google' }  // 添加
        maven { url 'https://maven.aliyun.com/repository/public' }  // 添加
        maven { url 'https://maven.aliyun.com/repository/public' }  // 添加
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.0'
    }
}

//Code ......

apply plugin: FlutterPlugin

class FlutterPlugin implements Plugin<Project> {
    //private static final String DEFAULT_MAVEN_HOST = "https://storage.googleapis.com";
    private static final String DEFAULT_MAVEN_HOST = "https://storage.flutter-io.cn";  // 修改

// Code ......

// Configure the Maven repository.
        String hostedRepository = System.env.FLUTTER_STORAGE_BASE_URL ?: DEFAULT_MAVEN_HOST
        String repository = useLocalEngine()
            ? project.property('local-engine-repo')
            : "$hostedRepository/download.flutter.io"
        rootProject.allprojects {
            repositories {
                maven {
                    url repository
                }
                maven { url 'https://maven.aliyun.com/repository/google' }  // 添加
                maven { url 'https://maven.aliyun.com/repository/public' }  // 添加
                maven { url 'https://maven.aliyun.com/repository/public' }  // 添加
            }
        }

2.修改项目文件：MyProject\android\flutter.gradle

buildscript {
    ext.kotlin_version = '1.4.32'
    repositories {
        //google()
        //mavenCentral()
        maven { url 'https://maven.aliyun.com/repository/google' }
        maven { url 'https://maven.aliyun.com/repository/public' }
        maven { url 'https://maven.aliyun.com/repository/public' }
    }

3.关闭 Android studio 编辑器，删除目录及所有子文件和子目录：C:\Users\userName\.gradle

??注意是 .gradle 目录，前面有个点，类似于 Linux 的隐藏目录。启动编译时，编辑器会重新下载此目录下的文件。Gradle 是一个开源的 Android 官方构建自动化工具，官网如下：Gradle Build Toolhttps://gradle.org/

?4.重启一下编辑器，步骤：File -> Invalidate Caches/Restart -> Invalidate and Restart