vijayinyoutube

body: Center(
        child: ElevatedButton(
          onPressed: () async {
            await homePageData.saveJsonData(rawData);
            homePageData.getJsonData();
          },
          child: const Text('Save Data'),
        ),
      ),

vijayinyoutube

class HomePageData {
  Future saveJsonData(jsonData) async {
    final prefs = await SharedPreferences.getInstance();
    var saveData = jsonEncode(jsonData);
    await prefs.setString('jsonData', saveData);
  }

  Future<void> getJsonData() async {
    final prefs = await SharedPreferences.getInstance();
    var temp = prefs.getString('jsonData') ?? jsonEncode(defaultData);

vijayinyoutube

final rawData = <String, dynamic>{'name': 'Alice', 'age': 20};

final defaultData = <String, dynamic>{
  'name': 'name not found.',
  'age': 00,
};

vijayinyoutube

class HomePageModel {
  final String name;
  final int? age;

  HomePageModel(
    this.name,
    this.age,
  );

  

vijayinyoutube

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: ()  {},
          child: const Text('Save Data'),

vijayinyoutube

Future<void> _changeOpacity() async {
  setState(() => _visible = !_visible);
  await Future.delayed(const Duration(milliseconds: 650));
  setState(() => showPayBtn = !showPayBtn);
  setState(() => _visible = !_visible);
}

vijayinyoutube

 AnimatedOpacity(
  opacity: _visible ? 1.0 : 0.0,
  duration: const Duration(milliseconds: 650),
  child: ElevatedButton(
    ...
  ),
),

vijayinyoutube

ElevatedButton(
 style: ElevatedButton.styleFrom(
 elevation: 0,
 primary: primaryColor,
 minimumSize: const Size(double.infinity, 50),
 shape: RoundedRectangleBorder(
 borderRadius: BorderRadius.circular(10.0),
  ),
 ),
 child: Text(

vijayinyoutube

void main() {
    Student()
    ..name = 'Alice'
    ..id = 'A01'
    ..method1()
    ..method2();
}

vijayinyoutube

void main() {
  Student student = Student();
  student.name='Alice';
  student.id='A01';
  student.method1();
  student.method2();
}