Flutter-unable to set coordinates in line charts? - flutter

Question

i'm facing issues in line charts. i'm fetching x and y data from sq lite database. and it should set
in line chart.when activity started chart showing blank. but only click on chart value is setting in
chart.
i'm using charts_flutter dart package for implementation.
where i did the mistake. any solutions.
Future graph_initialize() {
Future<List<Map>> noteListFuture1 = dbHelper.get_lactation_curve("${widget.value.tag}");//fetching data from databse
noteListFuture1.then((noteList) {
for(int i=0;i<noteList.length;i++){
print(noteList[i]["Days"].toString()+","+noteList[i]["Milk_Yield"].toString());
milking_data.add( new Sales(noteList[i]["Days"], noteList[i]["Milk_Yield"]));
}
_serieslineData.add(charts.Series(
colorFn: (__, _) => charts.ColorUtil.fromDartColor(Colors.red),
id: 'lac',
data: milking_data,// here data is setting
domainFn: (Sales sales, _) => sales.yearval,
measureFn: (Sales sales, _) => sales.salesval));
setState(() {
});
});}
#override
void initState() {
super.initState();
_serieslineData = List<charts.Series<Sales, int>>();
graph_initialize();//function call
}
Widget show_chart(){
return Padding(
padding: EdgeInsets.all(8),
child: Container(
height: 300,
child: Column(
children: <Widget>[
Text('Lactation Curve',
style: TextStyle(fontSize: 16, fontFamily: 'Montserrat',fontWeight: FontWeight.bold)),
Expanded(
child: charts.LineChart(_serieslineData,
animate: false,
domainAxis: charts.NumericAxisSpec(
tickProviderSpec:
new charts.BasicNumericTickProviderSpec(
desiredTickCount: 11,
),
viewport: charts.NumericExtents(
0,
300,
)),
animationDuration: Duration(seconds: 3),
behaviors: [
charts.ChartTitle('Milk Yield',
behaviorPosition: charts.BehaviorPosition.start),
charts.ChartTitle('Days in Milk',
behaviorPosition: charts.BehaviorPosition.bottom),
charts.ChartTitle(
'',
),
charts.ChartTitle(' ')
])),
Padding(
padding: const EdgeInsets.all(8.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[label(Colors.red,'Lac'),
label(Colors.lightBlueAccent,'Milk(kg)'),
label(Colors.amber,'A.I'),
label(Colors.green,'Pregnant'),
label(Colors.blueGrey,'Vaccination'),
label(Colors.black,'Treatment'),
],
),
)
],
),
),
);
}

Answer 1

You need a bool loading or isLoading to control because chart data is not ready yet
and when loading == true return CircularProgressIndicator() or Container()
bool loading = false;
Future graph_initialize() {
loading = true;
Future<List<Map>> noteListFuture1 = dbHelper.get_lactation_curve("${widget.value.tag}");//fetching data from databse
noteListFuture1.then((noteList) {
for(int i=0;i<noteList.length;i++){
print(noteList[i]["Days"].toString()+","+noteList[i]["Milk_Yield"].toString());
milking_data.add( new Sales(noteList[i]["Days"], noteList[i]["Milk_Yield"]));
}
_serieslineData.add(charts.Series(
colorFn: (__, _) => charts.ColorUtil.fromDartColor(Colors.red),
id: 'lac',
data: milking_data,// here data is setting
domainFn: (Sales sales, _) => sales.yearval,
measureFn: (Sales sales, _) => sales.salesval));
setState(() {
loading = false;
});
});}
Expanded(
child: loading? CircularProgressIndicator() : charts.LineChart(_serieslineData,
animate: false,
domainAxis: charts.NumericAxisSpec(
tickProviderSpec: