I'm new to Dart. This is my code:
class Point {
int x;
int y;
Point(this.x, this.y);
Point.same(int i) {
x = i;
y = i;
}
}
main() {}
I got this error when running it.
bin/dart1.dart:7:3: Error: This constructor should initialize field 'x' because its type 'int' doesn't allow null.
Point.same(int i) {
^
bin/dart1.dart:2:7: Context: 'x' is defined here.
int x;
^
bin/dart1.dart:7:3: Error: This constructor should initialize field 'y' because its type 'int' doesn't allow null.
Point.same(int i) {
^
bin/dart1.dart:3:7: Context: 'y' is defined here.
int y;
^
As I understand, the parameter int i of Point.same() is non-nullable, and I use it to initialize x and y (x = i; y = i;). Why it still asks me to initialize x and y? I even tried the following code and still got the same error:
class Point {
int x;
int y;
Point(this.x, this.y);
Point.same() {
x = 3;
y = 3;
}
}
main() {}
When initializing fields from a constructor without constructor parameters, use the initializer list. It runs prior to the constructor body and allow you to initialize final and non-nullable variables without marking them late.
class Point {
int x;
int y;
Point(this.x, this.y);
Point.same(int i) :
x = i,
y = i;
}
main() {}
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