Dart中如何使用头文件

Question

I have a list of about 100K entries that have this format:

final codes = <Results>[Results('ccc857'),
Results('dea105'),
Results('fad975'),
Results('abf307'),
Results('faf995'),...(continuing for 100K lines)

If I place these directly into main.dart android studio hangs.

I would like to have this as a header file abc.h but I don't know of a Dart equivalent.

Thank you.

Answer 1

Dart does not have any notion of header files.

You are asking to create 100K objects, each containing ~1 string. The compiler also needs 100K nodes to represent that source code, so that's a lot of objects. And a lot of code (your program will contain code for 100K different calls to the Result constructor).

Consider instead doing something like:

final codes = _createCodes();
static List<Result> _createCodes() {
  const strings = ["dea105", "fad975", "abf307", "faf995",
  "......", .... 
  "......"];
  return [for (var string in strings) Result(string)];
}

That is, don't repeat the entire expression 100K times, use a loop, and only have the part that differs between the iterations as separate code. That should reduce the overhead of your exceedingly large code.

No promises it won't hang anyway, with a 100K element list literal. Consider if you can load those strings from a file at run-time instead. Or maybe put them into one string literal:

final codes = _createCodes();
static List<Result> _createCodes() {
  const strings = "dea105fad975abf307faf995...."
  "...........",  
  ...
  ".......,...";
  return [for (var i = 0; i < strings.length; i++) 
      Result(strings.substring(i, i + 6))
  ];
}

(That does create an awful lot of strings at runtime, but only one at compile-time. One 600K character string literal. That might have its own problems.)