flutter的環境安裝配置問題

（1）安裝android SDK時，會出現Android license 的問題，将JAVA JDK降級到SE8就可以了，很多版本沒對應上，JAVA8是比較穩定的，包括後面的gradle也需要基于JAVA8

問題描述：[!] Android toolchain - develop for Android devices (Android SDK 27.0.3) ✗ Android license status unknown.

解決：安裝JAVA8後，運作 flutter doctor --android-licenses

（2） 卡在Running ‘gradle assembleDebug運作階段，引用國内阿裡雲的鏡像解決。

問題描述：Running Gradle task 'assembleDebug'...

解決：

  修改項目中`android/build.gradle`檔案

buildscript {
    repositories {
        //修改的地方
        //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:3.2.1'
    }
}

allprojects {
    repositories {
        //修改的地方
        //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' }
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

task clean(type: Delete) {
    delete rootProject.buildDir
}
           

 修改Flutter的配置檔案, 該檔案在`Flutter安裝目錄/packages/flutter_tools/gradle/flutter.gradle`

buildscript {
    repositories {
        //修改的地方
        //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:3.2.1'
    }
}