Your app isn’t using AndroidX

android/gradle.properties添加下面语句

android.enableJetifier=true
android.useAndroidX=true

Running Gradle task ‘assembleDebug’… 卡住

修改：android/build.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' }
    }
}

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' }
    }
}

修改：flutter安装目录/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' }
    }
}