尝试使用 flutter_screenutil package 和 Introduction_screen package 时，我在 flutter 中遇到延迟初始化错误

Question

The late initialization error comes when I add.w, .h, .sp to double values like,

top: 16.h

or

right: 16.w

Here is the code https://drive.google.com/file/d/1yN2AqKF2LOMFYkX9PzsTVz_o5hktSY0D/view?usp=sharing

These are the packages which I have installed

dev_dependencies:
  flutter_test:
    sdk: flutter
  google_fonts: 2.1.0
  flutter_screenutil: ^5.0.0+2
  page_transition: ^2.0.4
  introduction_screen: ^2.1.0

Answer 1

You need to initialize the ScreenUtil class just like it was provided in the example page here

class _HomePageState extends State<HomePage> {


 @override
  Widget build(BuildContext context) {

     //You need to add this line to your code
    //Set the fit size (fill in the screen size of the device in the design) If the design is based on the size of the 360*690(dp)
    ScreenUtil.init(
        BoxConstraints(
            maxWidth: MediaQuery.of(context).size.width,
            maxHeight: MediaQuery.of(context).size.height),
        designSize: Size(360, 690),
        minTextAdapt: true,
        orientation: Orientation.portrait);
    return Scaffold();
  }
}