flutter笔记

Error: Cannot run with sound null safety, because the following dependencies

don't support null safety:

解决方案：

flutter run --no-sound-null-safety

flutter build apk --no-sound-null-safety

变量以下划线（_）开头，在Dart语言中使用下划线前缀标识符，会强制其变成私有的。Dart中私有变量应该以final来修饰