在 Dart 中等待按键

Wait for a keypress in Dart

我想暂停我的 Dart 脚本(在网页中)的执行，直到用户点击一个键。以下代码有效，但我想知道是否有更好的方法：

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import 'dart:html';
import 'dart:async';

StreamSubscription sub;

Future main() async {
KeyboardEvent k = await getkey();
print(k.keyCode.toString());
}

Future<KeyboardEvent> getkey() async {
Completer<KeyboardEvent> c = new Completer<KeyboardEvent>();
sub = document.onKeyDown.listen((KeyboardEvent e){
sub.cancel();
c.complete(e);
});
return c.future;
}

更新：Gunter 的以下解决方案是理想的。上面的代码缩短为：

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但是，如果我想过滤按键，我想我会回到以前的样式：

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import 'dart:html';
import 'dart:async';

StreamSubscription sub;

Future main() async {
KeyboardEvent k = await getkey([KeyCode.A,KeyCode.B,KeyCode.C,KeyCode.D]);
print(k.keyCode.toString());
}

Future<KeyboardEvent> getkey([List<int> lst]) async {
Completer<KeyboardEvent> c = new Completer<KeyboardEvent>();
sub = document.onKeyDown.listen((KeyboardEvent e){
if ((lst==null)||(lst.contains(e.keyCode))){
sub.cancel();
c.complete(e);
}
});
return c.future;
}

是吗？

更新再次感谢Gunter！结果是：

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Future<KeyboardEvent> getkey([List<int> lst]) async {
return document.onKeyDown.firstWhere((KeyboardEvent e)=>((lst==null)||(lst.contains(e.keyCode))));
}

用法如下：

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import 'dart:html';
import 'dart:async';

Future main() async {
KeyboardEvent k = await getkey();
print(k.keyCode.toString());
KeyboardEvent k = await getkey([KeyCode.A,KeyCode.B,KeyCode.C,KeyCode.D]);
print(k.keyCode.toString());
}