进入AS后，device显示loading，点击运行提示无法找到设备
1 开启模拟器
2 运行flutter devices 能够找到设备
3 重启as
无法使用flutter
AS要3.6 才能使用Flutter
执行flutter 命令提示 (This is taking an unexpectedly long time.)
因为墙的原因，建议按照guide填写国内的源。
mac Terminal：
cd ~
open .bash_profile
添加下面两行环境变量
#国内用户需要设置
export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
package:http/http.dart 找不到
dependencies:
http: ^0.11.0 // --加入这行
flutter:
sdk: flutter
https://blog.csdn.net/Dreamfine/article/details/83859915
Dio网络请求返回异常，但Flutter HttpClient正常访问
DioError [DioErrorType.DEFAULT]: Error on line 1, column 17: Invalid media type: expected no more input.
原因，本地服务器，application/json,charset=utf-8 逗号应该改为分号
return HttpResponse(json.dumps(result, ensure_ascii=False), content_type="application/json;charset=utf-8")
Failed assertion: line xxx pos xxx: 'data != null'
错误示范
var text = null;
new Text（text）;
传入的Text为空就会导致这个错误，解决办法就是不传空值
Failed assertion: line xxx pos xxx: 'data != null'
