Dropdown button menu item is not displaying after selecting the item. When users needed to select a single item from a list of the available items, but flutter is not displaying the selected item

class TaskTitleDiaglogscreen extends StatefulWidget {
  const TaskTitleDiaglogscreen({
    super.key, });

  @override
  State<TaskTitleDiaglogscreen> createState() => _TaskTitleDiaglogscreenState();
}

class _TaskTitleDiaglogscreenState extends State<TaskTitleDiaglogscreen> {
 
  @override
  Widget build(BuildContext context) {
    final taskpriority = [
      'Urgent',
      'High priority',
      'Important',
      'Medium priority',
      'Not important',
      'Low priority',
    ];
    String? selecteditem;

    return AlertDialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          InputDecorator(
            decoration: InputDecoration(
              labelText: 'Select Priority',
              labelStyle: TextStyle(fontSize: 20),
              border:
                  OutlineInputBorder(borderRadius: BorderRadius.circular(20.0)),
              contentPadding: EdgeInsets.all(10),
            ),
            child: ButtonTheme(
              materialTapTargetSize: MaterialTapTargetSize.padded,
              child: DropdownButton(
                  value: selecteditem,
                  isExpanded: true,
                  icon: Icon(Icons.keyboard_double_arrow_down_rounded),
                  items: taskpriority.map(buildMenuitem).toList(),
                  onChanged: (value) {
                    setState(() {
                      selecteditem = value;
                    });
                    print(selecteditem);
                  }),
            ),
          )
        ],
      ),
    );
  }

  DropdownMenuItem<String> buildMenuitem(String priority) => DropdownMenuItem(
        value: priority,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text(priority),
             CircleAvatar(
              radius: 10,
              backgroundColor: _getColor(priority),
            )
          ],
        ),
      );

  Color _getColor(String value) {
    switch (value) {
      case 'Urgent':
        return Colors.red;
      case 'High priority':
        return Color.fromARGB(255, 243, 144, 144);
      case 'Important':
        return Colors.green;
      case 'Medium priority':
        return Colors.lightGreenAccent;
      case 'Not important':
        return Colors.blue;
      case 'Low priority':
        return Colors.lightBlueAccent;
      default:
        return Colors.black;
    }
  }
} 

CodePudding user response：

You need to define variable outside the build method, else it will reassign the default value.

class _TaskTitleDiaglogscreenState extends State<TaskTitleDiaglogscreen> {
  final taskpriority = [
    'Urgent',
    'High priority',
    'Important',
    'Medium priority',
    'Not important',
    'Low priority',
  ];
  String? selecteditem;
  @override
  Widget build(BuildContext context) {