control & disable a dropdown button in flutter? - flutter

Question

I wanted to control a drop-down button and make it unclickable using a button.
Is there any way to make it disable. Basically not allowing it able to change.
new DropdownButton(
value: animalName,
items: animals.map(
(String value) {
return new DropdownMenuItem<String>(
value: value,
child: new Text('$value'),
);
},
).toList(),
onChanged: (value) {
setState(() {
animalName = value;
});
},
),
So this is the code I currently use on the drop-down button, but i cant disabled it.

Answer 1

Found this in the DropdownButton docs:
If items or onChanged is null, the button will be disabled, the down arrow will be grayed out, and the disabledHint will be shown (if provided)
DropdownButton(
onChanged: null,
items: [...],
)

Answer 2

This isn't what you want to hear, but I don't think there's currently an easy way. I experimented with simply removing all the items and that causes a nice little crash. Maybe worth raising an issue with the flutter people on github...
There is an alternative that may be good enough for you for now. If you wrap your DropdownButton in an IgnorePointer, when you want it to be disabled you can change IgnorePointer's ignoring property to true.
That way if the user taps on it, it won't do anything.
But you'll probably want to indicate to the user somehow that it's disabled as well, something like setting the hint text (as it's grey).
child: new IgnorePointer(
ignoring: true,
child: new DropdownButton(
hint: new Text("disabled"),
items: ["asdf", "wehee", "asdf2", "qwer"].map(
(String value) {
return new DropdownMenuItem<String>(
value: value,
child: new Text('$value'),
);
},
).toList(),
onChanged: (value) {},
),

Answer 3

You can make DropdownButtonFormField or DropdownButton disabled if set onChanged to null, and if you want that dropdown still shows selected value you must set disabledHint. For example:
DropdownButtonFormField<String>(
disabledHint: Text(_selectedItem),
value: _selectedItem,
onChanged: enabled ? (value) => setState(() => _selectedItem = value) : null,
items: items.map<DropdownMenuItem<String>>((item) {
return DropdownMenuItem(
value: item,
child: Text(item),
);
}).toList(),
)

Answer 4

Just wrap it with IgnorePointer widget to make DropdownButton disable
IgnorePointer(
ignoring: enabled,
child: new DropdownButton(
value: animalName,
items: animals.map(
(String value) {
return new DropdownMenuItem<String>(
value: value,
child: new Text('$value'),
);
},
).toList(),
onChanged: (value) {
setState(() {
animalName = value;
});
},
),
);

Answer 5

If items or onChanged is null, the button will be disabled, the down
arrow will be grayed out, and the disabledHint will be shown (if
provided)
So something like this should work:
DropdownButton<String>(
...
onChanged: this.enabled ? (id) => setState(() => this.id = id) : null,
)

Answer 6

okay, i found a trick that satisfied me
i wanted it hide/show the DropdownButton depending on CheckboxListTile
in StatefulWidget Class
first create a function ex:
_buildDropDown(bool enable) {
if (enable) {
return DropdownButton<String>(
hint: Text("Hint"),
items: <String>[
'item 1',
'item 2',
'item 3',
].map((String value) {
return new DropdownMenuItem<String>(
value: value,
child: new Text(value),
);
}).toList(),
onChanged: (value) {},
);
} else { // Just Divider with zero Height xD
return Divider(color: Colors.white, height: 0.0);
}
}
and now in build
bool enable = true;
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
CheckboxListTile(
title: const Text('Switcher'),
selected: true,
value: enable,
onChanged: (bool value) {
setState(() {
enable = value;
});
},
),
_buildDropDown(enable),
],
);
}
now every time you change enable it will display and hide the DropdownButton

Answer 7

DropdownButtonFormField(
onChange: isDisable ? null : (str){
},
disabledHint: isDisable ? null : Text('Your hint text'),
...
)
For disable
onChange: null
For disable Caption
disabledHint: Text('Your hint text')

Answer 8

//add widget'AbsorbPointer' true-disable,false-enable
// isEditable = ture
AbsorbPointer(
absorbing: isEditable
DropdownButton(
onChanged: null,
items: [...],
)
)

Answer 9

Simple:
decoration:InputDecoration(enabled: false),