how to execute the API when the textfield is filled BLOC FLUTTER? - flutter

Question

how to execute the API when the textfield is filled. so when the textfield is filled it starts executing the API.
I've tried making a check function that works if the textfield is not null then I can only start the API execution. in the following ways:
in the block I make a check function to check whether the textfield (_prefix) is filled or not but this function is an error when called in inStState in the UI section.
BLOC :
class DenomPulsaBloc {
final _repository = EresidenceRepository();
final _prefix = BehaviorSubject<String>();
SharedPreferences sPrefs;
final BehaviorSubject<List<Payload>> _subject = BehaviorSubject<List<Payload>>();
Function(String) get prefix => _prefix.sink.add;
cek() async{
if(_prefix.value.length >= 3) {
denomPulsa();
}else{
print("GAGAL");
}
}
denomPulsa() async{
try{
sPrefs = await SharedPreferences.getInstance();
ListPulsaResponses responses = await _repository.listDenomPulsa(sPrefs.getString("userid"), sPrefs.getString("password"), sPrefs.getString("imei"),
sPrefs.getString("coordinate"), sPrefs.getString("bit61"), sPrefs.getString("bit62"), _prefix.value);
List<Payload> list = responses.data.payload;
_subject.sink.add(list);
print(list);
}catch(e){
print(e.toString());
_subject.sink.add(e);
}
}
dispose(){
_subject.close();
_prefix.close();
}
BehaviorSubject<List<Payload>> get subject => _subject;
}
UI :
class _PulsaPageState extends State<PulsaPage> {
DenomPulsaBloc denomPulsaBloc;
int selectedCard = -1;
#override
void initState() {
super.initState();
denomPulsaBloc = DenomPulsaBloc();
denomPulsaBloc.cek();
}
#override
void dispose() {
denomPulsaBloc.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: DefaultTabController(
length: 2,
child: Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
backgroundColor: Colors.white,
brightness: Brightness.light,
elevation: 0.0,
leading: InkWell(
onTap: () {
Navigator.of(context).pop();
},
child: Icon(
Icons.arrow_back_ios,
color: Colors.black,
size: SizeConfig.texIconSize,
),
),
),
body: SafeArea(
child: Container(
height: SizeConfig.screenHeight,
width: SizeConfig.screenWidth,
padding: EdgeInsets.symmetric(horizontal: SizeConfig.widthMultiplier * 4),
child: Column(
mainAxisSize: MainAxisSize.max,
children: <Widget>[
Container(
alignment: Alignment.centerLeft,
child: Text(
'Pulsa',
style: AppTheme.styleSubTitleBoldLarge,
)
),
Container(
margin: EdgeInsets.only(top: SizeConfig.heightMultiplier * 4),
decoration: BoxDecoration(
boxShadow: <BoxShadow>[
BoxShadow(blurRadius: 5.0, color: Colors.black12)
]
),
child: ClipRRect(
borderRadius: BorderRadius.circular(8.0),
child: Container(
padding: EdgeInsets.all(SizeConfig.heightMultiplier * 2),
color: Colors.white,
child: Row(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
Expanded(
flex: 1,
child:
Container(
child: Icon(Icons.phone_android, color: Colors.green, size: SizeConfig.texIconSize,),
),
),
Expanded(
flex: 9,
child: Container(
margin: EdgeInsets.only(left: SizeConfig.widthMultiplier * 3),
child:Column(
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
child: Text(
'Number',
style: AppTheme.styleSubTitle,
),
),
Container(
child: Stack(children: <Widget>[
Container(
height: SizeConfig.heightMultiplier * 5.5,
child: TextFormField(
inputFormatters: [
new LengthLimitingTextInputFormatter(13)
],
style: AppTheme.styleSubTitleBlackSmall,
decoration: const InputDecoration(
hintText: '090900909'
),
onChanged: denomPulsaBloc.prefix,
),
),
Align(
alignment: Alignment.centerRight,
child: Container(
alignment: Alignment.centerRight,
height: SizeConfig.texIconSize,
width: SizeConfig.texIconSize,
margin: EdgeInsets.only(right: SizeConfig.widthMultiplier * 9, top: SizeConfig.heightMultiplier * 1.5),
child: Image.asset(
"res/images/xl.png",
fit: BoxFit.fill,
)
),
),
Align(
alignment: Alignment.centerRight,
child: Container(
margin: EdgeInsets.only(top: SizeConfig.heightMultiplier * 1.5),
child: InkWell(
onTap: (){},
child: Icon(
Icons.close,
size: SizeConfig.texIconSize,
),
)
)
)
]),
),
]
),
)
),
],
),
),
),
),
Expanded(
child: Container(
width: SizeConfig.screenWidth,
height: SizeConfig.screenHeight,
child: StreamBuilder(
stream: denomPulsaBloc.subject,
builder: (context, AsyncSnapshot<List<Payload>> snapshot) {
if (snapshot.hasData) {
// print(snapshot.data);
return listDenomPulsa(snapshot);
}else{
Error();
}
return Container();
},
),
),
),
],
),
),
),
),
),
);
}