javascript - 什么是 Angular Material 中的 mdLiveAnnouncer 及其工作原理？

Question

谁能用这段代码向我解释一下 $mdLiveAnnouncer。

module.controller('AppCtrl', function($mdLiveAnnouncer) {
  // Basic announcement (Polite Mode)
  $mdLiveAnnouncer.announce('Hey Google');

  // Custom announcement (Assertive Mode)
  $mdLiveAnnouncer.announce('Hey Google', 'assertive');
});

Answer 1

根据他们的 documentation .

The $mdLiveAnnouncer service is internally used for components to provide proper accessibility. $mdLiveAnnouncer.announce(message, politeness);

Announces messages to supported screenreaders.

当您说它什么都不做时...您是否尝试过在支持屏幕阅读器的设备上运行它？

根据 GitHub 上的文档(链接在上面的文档中):

• Both JAWS and NVDA over IE11 will not announce anything without a non-zero timeout.
• With Chrome and IE11 with NVDA or JAWS, a repeated (identical) message won't be read a second time without clearing and then using a non-zero delay. (using JAWS 17 at time of this writing).