Flutter SQFlite populate a dropdown list from the database - flutter

Question

I am trying to read the list part of a dropdown list from my SQFlite database, and can't work out how.
Query from database_helper
Future<List<Map>> getFieldData(String animal, String fieldName)
var dbClient = await db;
return await dbClient.rawQuery('SELECT lbOption FROM jkAssessData Where lbAnimal = \'${animal}\' AND lbField = \'${fieldName}\'');
}
I can get it to work with a static list of values
final List<String> _animals = <String>['CATTLE', 'SHEEP', 'GOAT'];
to populate this dropdown list
FormField<String>(
builder: (FormFieldState<String> state) {
return InputDecorator(
decoration: InputDecoration(
labelText: 'Animal Type',
errorText: state.hasError ? state.errorText : null,
),
isEmpty: _animal == '',
child: DropdownButtonHideUnderline(
child: DropdownButton<String>(
value: _animal,
isDense: true,
onChanged: (String newValue) {
setState(() {
assessHed.asAnimal = newValue;
_animal = newValue;
state.didChange(newValue);
});
},
items: _animals.map((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}).toList(),
),
),
);
},
validator: (val) {
//return val != 'SUMMARY' ? 'DETAIL' : 'Please select Type';
return null;
},
),
It's part of several fields on a Form

Answer 1

Start by using the call in the initState or in a onPressed of a RaisedButton.
Place this initState and _loadAnimals method in your State Widget.
List<String> _animals = <String>[];
#override
initState() {
super.initState();
// when loading your widget for the first time, loads animals from sqflite
_loadAnimals();
}
_loadAnimals() async {
// gets data from sqflite
final loadedAnimals = await getFieldData('CATTLE','Breed1');
setState(() {
// converts sqflite row data to List<String>, updating state
_animals = loadedAnimals.map((Map<dynamic, dynamic> row) => row["lbOption"] as String).toList();
});
}
Or you could change the getFieldData to return a List<String> instead of a List<Map>:
Future<List<String>> getFieldDataAsString(String animal, String fieldName) async {
var dbClient = await db;
var results = await dbClient.rawQuery('SELECT lbOption FROM jkAssessData Where lbAnimal = \'$animal\' AND lbField = \'$fieldName\'');
return results.map((Map<String, dynamic> row) {
return row["lbOption"] as String;
}).toList();
}