Flutter DropdownButton widget with Getx - flutter

Question

I'm in the process of learning GetX state management and stumble upon the DropdownButton widget. How do I update the selected value with the selected value cannot be observed. Here is my DropdownButton widget
DropdownButton(
hint: Text(
'Book Type',
),
onChanged: (newValue) {
print(newValue);
},
value: selectedType,
items: bookController.listType.map((selectedType) {
return DropdownMenuItem(
child: new Text(
selectedType,
),
value: selectedType,
);
}).toList(),
),
The
var selectedType;
declared in the widget build. I tried to make this variable observable but the layout throws an overflow error. I also wrap the widget with obx but still, it throws the same error. How do exactly this widget implement using GetX. I'm pulling my hair here. I can work with other widgets with getX.

Answer 1

First create your controller class.
class BookController extends GetxController {
// It is mandatory initialize with one value from listType
final selected = "some book type".obs;
void setSelected(String value){
selected.value = value;
}
}
On the view, instantiate your Controller and wrap the DropdownButton with an Obx widget:
BookController bookcontroller = BookController();
Obx( () => DropdownButton(
hint: Text(
'Book Type',
),
onChanged: (newValue) {
bookController.setSelected(newValue);
},
value: bookController.selected.value,
items: bookController.listType.map((selectedType) {
return DropdownMenuItem(
child: new Text(
selectedType,
),
value: selectedType,
);
}).toList(),
)
),

Answer 2

if you don't want to use observable variable then wrap your dropdown with getBuilder and in onChange function just update your controller like
onChanged: (newValue) {
bookController.currentDropdownValue=newValue;
bookController.update();
},
Example
//Controller
class HomeController extends GetxController {
var selectedDrowpdown = 'abc';
List dropdownText = ['abc', 'def', 'ghi'];
}
//dropdown button in Ui
DropdownButton(
hint: Text(
'Book Type',
),
onChanged: (newValue) {
homeController.selectedDrowpdown=newValue;
homeController.update();
},
value: homeController.selectedDrowpdown,
items: [
for (var data in homeController.dropdownTextList)
DropdownMenuItem(
child: new Text(
data,
),
value: data,
)
])

Answer 3

final selected = "".obs;
BookController bookcontroller = BookController();
Obx( () => DropdownButton(
hint: Text(
'Book Type',
),
onChanged: (newValue) {
bookController.setSelected(newValue);
},
value: bookController.selected.value==""?null:bookController.selected.value,
items: bookController.listType.map((selectedType) {
return DropdownMenuItem(
child: new Text(
selectedType,
),
value: selectedType,
);
}).toList(),
)
),
Try this, this worked for me.