I'm receiving a syntax error from Android Studio when creating a list in Flutter (Dart).
Even in the simplest form copied from the Flutter documentation, I get the same error.
the code:
var simonSequence = new List<int>(3);
var c = simonSequence[0]; //error here
final anEmptyListOfDouble = <int>[];
anEmptyListOfDouble[0]=0; //also error here
give an error on the line that accesses the list element.
any suggestions are appreciated.
because you are writing the code inside the class scope, while you must be writing it in a function.
this is what you are doing
class _SimonState extends State<Simon>{
//other codes
var simonSequence = new List<int>(3);
var c = simonSequence[0]; //error
final anEmptyListOfDouble = <int>[];
anEmptyListOfDouble[0]=0; //error
}
this is what your code SHOULD be like
class _SimonState extends State<Simon>{
//other codes
//some function you want your code to be called from
void anyFunction(){
var simonSequence = new List<int>(3);
var c = simonSequence[0]; //error
final anEmptyListOfDouble = <int>[];
anEmptyListOfDouble[0]=0; //error
}
@override
Widget build(BuildContext context) {
//then you will call your function anywhere you need like here
//for example
return RaisedButton(
onPressed:(){
anyFunction();
}
);
}
}
It simply because you're trying to access the declared variable within the class scope. It's marked as error because it's not a declaration for a variable. See the following code and its comment for details:
class _SimonState extends State<Simon>{
// Here you can only declare your variables.
// Or declaring a method.
var simonSequence = new List<int>(3);
var c = simonSequence[0]; // Error! This is not a variable declaration.
final anEmptyListOfDouble = <int>[];
anEmptyListOfDouble[0]=0; // Error! This is not a variable declaration.
...
void anotherMethod() {
...
// Correct, your accessing the variable here.
var c = simonSequence[0];
}
...
}
