How to get a context in a function? - flutter

Question

I need to get a context for my Navigator push, i have this Navigator on my function _navigate. I try something like _navigate(BuildContext context) but i got an error like "type (BuildContext) => dynamic is not a subtype of type() => void. It's the first context of Navigator.push i don't know how to get it.
import 'package:flutter/material.dart';
import 'package:pandora_etna/assistance.dart';
import 'dart:math';
import 'package:vector_math/vector_math.dart' show radians;
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
backgroundColor: Color(0xFFB3E5FC),
body: SizedBox.expand(child: RadialMenu())),
);
}
}
class RadialMenu extends StatefulWidget {
createState() => _RadialMenuState();
}
class _RadialMenuState extends State<RadialMenu>
with SingleTickerProviderStateMixin {
AnimationController controller;
void initState() {
super.initState();
controller =
AnimationController(duration: Duration(milliseconds: 900), vsync: this);
}
Widget build(BuildContext context) {
return RadialAnimation(controller: controller);
}
}
class RadialAnimation extends StatelessWidget {
RadialAnimation({Key key, this.controller})
: scale = Tween<double>(
begin: 1.5,
end: 0.0,
).animate(
CurvedAnimation(parent: controller, curve: Curves.fastOutSlowIn),
),
translation = Tween<double>(
begin: 0.0,
end: 100.0,
).animate(
CurvedAnimation(parent: controller, curve: Curves.linear),
),
rotation = Tween<double>(begin: 0.0, end: 360.0).animate(
CurvedAnimation(
parent: controller,
curve: Interval(
0.0,
0.7,
curve: Curves.decelerate,
)),
),
super(key: key);
final AnimationController controller;
final Animation<double> scale;
final Animation<double> translation;
final Animation<double> rotation;
build(context) {
return AnimatedBuilder(
animation: controller,
builder: (context, builder) {
return Transform.rotate(
angle: radians(rotation.value),
child: Stack(alignment: Alignment.center, children: [
_buildButton(0, _close,
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.chartBar),
_buildButton(60, _close,
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.clipboard),
_buildButton(120, _close,
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.chartBar),
_buildButton(180, _close,
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.book),
_buildButton(240, _close,
color: Color(0xFF29B6F6),
icon: FontAwesomeIcons.arrowsAltV),
_buildButton(300, _navigate,
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.phoneAlt),
_buildButton(360, _close,
color: Color(0xFF29B6F6),
icon: FontAwesomeIcons.compressAlt),
Transform.scale(
scale: scale.value - 1.5,
child: FloatingActionButton(
child: Icon(FontAwesomeIcons.timesCircle),
onPressed: _close,
backgroundColor: Color(0xFF29B6F6)),
),
Transform.scale(
scale: scale.value,
child: FloatingActionButton(
child: Icon(FontAwesomeIcons.solidDotCircle),
onPressed: _open,
backgroundColor: Color(0xFF29B6F6)),
),
]));
});
}
_buildButton(double angle, Function callback, {Color color, IconData icon}) {
final double rad = radians(angle);
return Transform(
transform: Matrix4.identity()
..translate(
(translation.value) * cos(rad), (translation.value) * sin(rad)),
child: FloatingActionButton(
child: Icon(icon), backgroundColor: color, onPressed: callback));
}
_open() {
controller.forward();
}
_close() {
controller.reverse();
}
_navigate(BuildContext context) {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Assistance()));
}
}

Answer 1

I think it is because you lose your context argument when calling _buildButton.
/// By writing your Function parameter like this you will pass the
/// BuildContext parameter needed.
_buildButton(
300,
() => _navigate(context),
color: Color(0xFF29B6F6),
icon: FontAwesomeIcons.phoneAlt
),

Answer 2

You need to pass BuildContext to the _navigate function when you reference it. You could do this with an anonymous function. _buildButton(300,(context) => _navigate(context), ...

Answer 3

It doesn't work because you didn't give the context parameter of the function's method. I guess so
_buildButton(300, _navigate(context),
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.phoneAlt),

Answer 4

Try out below example for more idea:-
_buildButton(300, _navigate(context), // Added Context here,It will contains context of build function
color: Color(0xFF29B6F6), icon: FontAwesomeIcons.phoneAlt),
_navigate(BuildContext context) {
Navigator.push(
context, new MaterialPageRoute(builder: (context) => Assistance()));
}

Answer 5

When calling your function _buildButton you must wrap _navigate function into another function, since it need your current context to work
Try this
_buildButton(300, () {
_navigate(context);
}, color: Color(0xFF29B6F6), icon: FontAwesomeIcons.phoneAlt),