Being new in the flutter world, I am wondering if someone can give me a hand with the following issue. I want to display a GeoJSON after a checkbox is checked but not sure how to call it:
CheckboxListTile(
title: Text(
'Test query',
),
value: _isCheckedPoMt,
onChanged: (bool? newValue) {
setState(() {
_isCheckedPoMt = newValue ?? false;
});
},
),
where:
//====================
// issue starts here =
//====================
if (_isCheckedPoMt) {
GeoJsonLayer.asset(
'assets/data/all.geojson',
styleDefaults: GeoJsonStyleDefaults(
strokeColor: Colors.black,
strokeOpacity: 0.5,
strokeWidth: 2.5,
),
),
}
//========================
It seems that I am missing something in the if (_isCheckedPoMt) { part because it keeps saying The element type 'Set<GeoJsonLayer>' can't be assigned to the list type 'Widget'.dartlist_element_type_not_assignable.
What would it be wrong here? Any help is appreciated,
As mentioned by Omi Shah, using curly braces {} inside a list can unintentionally create a Set rather than a adding the item directly. To fix the issue, you should avoid placing the curly braces around the object/widget inside a conditional statement. Instead, directly insert the widget using an inline if statement without additional braces, like this:
body: Stack(
children: [
Center(
child: FlutterMap(
options: MapOptions(
initialCenter: const LatLng(10, 33.5),
initialZoom: 6.3,
),
children: [
TileLayer(
tileProvider: NetworkTileProvider(
headers: {
'User-Agent': 'flutter_map/1.1.1',
},
),
urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
),
GeoJsonLayer.asset(
'assets/data/line1.geojson',
styleDefaults: GeoJsonStyleDefaults(
strokeColor: Colors.red,
strokeOpacity: 0.5,
strokeWidth: 2.5,
),
),
if (_isCheckedPoMt)
GeoJsonLayer.asset(
'assets/data/all.geojson',
styleDefaults: GeoJsonStyleDefaults(
strokeColor: Colors.black,
strokeOpacity: 0.5,
strokeWidth: 2.5,
),
),
],
),
),
],
)