Flutter: how to set the height of a dropdown in Flutter - flutter

Question

I have a dropdown list in my flutter app that has about 30 items in it. When it is selected I see the values but it takes up whole screen.
How can I control the height of the selected list so that it does not overlay the entire screen (maybe show 10 items with a scroll)
Here is my code
Widget buildCategoryFormField(candidateModel) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text("Job category"),
SizedBox(
height: 5,
),
FormField(
builder: (FormFieldState state) {
return InputDecorator(
decoration: InputDecoration(
border: OutlineInputBorder(
borderSide: BorderSide(
color: Colors.grey,
),
),
enabledBorder: OutlineInputBorder(
borderSide: BorderSide(
color: Colors.grey,
),
),
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(
color: Colors.blue,
),
),
// hintText: "firstname *",
// labelText: "job category",
errorText: state.hasError ? state.errorText : null,
labelStyle: TextStyle(
color: Colors.grey,
),
),
isEmpty: _selectedjobCategory == '',
child: new DropdownButtonHideUnderline(
child: new DropdownButton(
style: TextStyle(fontSize: 18, color: Palette.GREY),
value: _selectedjobCategory,
isDense: true,
onChanged: (String newValue) {
setState(() {
_selectedjobCategory = newValue;
state.didChange(newValue);
});
},
items: JOB_CATEGORY.map((String value) {
return new DropdownMenuItem(
value: value,
child: new Text(value),
);
}).toList(),
),
),
);
},
validator: (val) => validateJobCategory(val),
),
],
);
}

Answer 1

You can define menuMaxHeight on DropdownButton to set maximum height of the expanded dropdown list items.
Expanded(
/// LayoutBuilder can be used to fetch the parent widget's dimensions
child: LayoutBuilder(builder: (context, constraints) {
return Center(
child: DropdownButton<String>(
/// Set dropdown list max height
menuMaxHeight: constraints.maxHeight,
value: dropdownValue,
items: dropdownItems,
),
);
}
)
Adding pagination to the dropdown list is feasible, but this will require creating a custom DropdownButton class. Design-wise, it would be better to break the list into smaller chunks (i.e. by categories) if you'll need to display >50 items in the dropdown.