'yield'关键字在颤动中起什么作用? [英] What does 'yield' keyword do in flutter?

问题描述

yield关键字在Dart中实际上起什么作用?

What does the yield keyword actually do in Dart?

推荐答案

yield为周围的async*函数的输出流添加一个值.就像return，但不会终止该函数.

yield adds a value to the output stream of the surrounding async* function. It's like return, but doesn't terminate the function.

请参见 https://dart.dev/guides/language/language-tour#generators

Stream asynchronousNaturalsTo(n) async* {
  int k = 0;
  while (k < n) yield k++;
}

执行yield语句时，它将对表达式的求值结果添加到流中.它不一定要挂起(尽管在当前的实现中会挂起).

When the yield statement executes, it adds the result of evaluating its expression to the stream. It doesn’t necessarily suspend (though in the current implementations it does).

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