Flutter TextEditingController retain value without hitting done button - flutter

Question

Simple Add Place widget
Title Text Field
Container - Render image from camera
Button - Activates camera device
I thought having a controller connected to TextField would automatically save the state of the input value. However, from my example, if I input the text without click "done" and immediately click on "Take Picture" button. The TextField input value is cleared after coming back from camera operation.
How to Reproduce Problem:
Input text into the field
Immediately click on the Camera button without click done / check or hit enter on the keyboard
Take a picture confirm.
Come back to page the TextField is empty
Example Code:
AddPlacePage StatefulWidget
Column(
children: <Widget>[
TextField(
decoration: InputDecoration(labelText: 'Title'),
controller: _titleController,
),
ImageInput(),
],
),
ImageInput StatefulWidget
class _ImageInputState extends State<ImageInput> {
File _storedImage;
Future<void> _takePicture() async {
final imageFile = await ImagePicker.pickImage(
source: ImageSource.camera,
maxWidth: 600,
);
setState(() {
_storedImage = imageFile;
});
...
}
#override
Widget build(BuildContext context) {
return Row(
children: <Widget>[
Container(
...
child: _storedImage != null
? Image.file(
_storedImage,
fit: BoxFit.cover,
width: double.infinity,
)
: Text(
'No Image Taken',
textAlign: TextAlign.center,
),
alignment: Alignment.center,
),
Expanded(
child: FlatButton.icon(
icon: Icon(Icons.camera),
label: Text('Take Picture'),
textColor: Theme.of(context).primaryColor,
onPressed: () => _takePicture(),
),
),
],
);
}
}
Question:
How can I modify TextField's controller to retain input value even after exiting the application to access device camera?
TextField(
decoration: InputDecoration(labelText: 'Title'),
controller: _titleController,
),
I did try to create a local variable and try to use onChange:
String _inputValue
build(BuildContext context){
...
TextField(
decoration: InputDecoration(labelText: 'Title'),
controller: _titleController,
onChange: (value) => _inputValue = value;
),
However the effect is the same once returning from the camera as Flutter re-reders the page, both _inputValue and _titleController.text is cleared.
Example code:
https://github.com/erich5168/flutter_camera_example

Answer 1

You can use share preferences to save the String to device then call it when you back to text field. This is how I implement:
class LocalStorage {
static SharedPreferences instance;
static Future init() async {
instance = await SharedPreferences.getInstance();
}
static dynamic getValue(String key, dynamic emptyValue) {
if (LocalStorage.instance.containsKey(key)) {
return LocalStorage.instance.get(key);
}
return emptyValue;
}
}
set it to text field:
TextEditingController _usernameController =
new TextEditingController(text: LocalStorage.getValue('UserName', ''));