javascript - Material design web MDCTab：在activateTab之后没有发出交互事件

Question

我正在使用这个

https://material.io/develop/web/components/tabs/tab-bar/

制作标签栏

<link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
<link rel="stylesheet" type="text/css" href="https://unpkg.com/material-components-web@latest/dist/material-components-web.min.css">
<script src="https://unpkg.com/material-components-web@latest/dist/material-components-web.min.js"></script>

<div class="mdc-tab-bar" role="tablist">
    <div class="mdc-tab-scroller">
        <div class="mdc-tab-scroller__scroll-area">
            <div class="mdc-tab-scroller__scroll-content">

                <button class="mdc-tab mdc-tab--active" role="tab" aria-selected="true" tabindex="0">
                    <span class="mdc-tab__content">
                        <span class="mdc-tab__icon material-icons" aria-hidden="true">title</span>
                        <span class="mdc-tab__text-label">Name</span>
                    </span>
                    <span class="mdc-tab-indicator mdc-tab-indicator--active">
                        <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
                    </span>
                    <span class="mdc-tab__ripple"></span>
                </button>
                <button class="mdc-tab" role="tab" aria-selected="true" tabindex="0">
                    <span class="mdc-tab__content">
                        <span class="mdc-tab__icon material-icons" aria-hidden="true">style</span>
                        <span class="mdc-tab__text-label">Tags</span>
                    </span>
                    <span class="mdc-tab-indicator">
                        <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
                    </span>
                    <span class="mdc-tab__ripple"></span>
                </button>
                <button class="mdc-tab" role="tab" aria-selected="true" tabindex="0">
                    <span class="mdc-tab__content">
                        <span class="mdc-tab__icon material-icons" aria-hidden="true">favorite</span>
                        <span class="mdc-tab__text-label">Status</span>
                    </span>
                    <span class="mdc-tab-indicator">
                        <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
                    </span>
                    <span class="mdc-tab__ripple"></span>
                </button>
                <button class="mdc-tab" role="tab" aria-selected="true" tabindex="0">
                    <span class="mdc-tab__content">
                        <span class="mdc-tab__icon material-icons" aria-hidden="true">warning</span>
                        <span class="mdc-tab__text-label">Restriction</span>
                    </span>
                    <span class="mdc-tab-indicator">
                        <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
                    </span>
                    <span class="mdc-tab__ripple"></span>
                </button>
                <button class="mdc-tab" role="tab" aria-selected="true" tabindex="0">
                    <span class="mdc-tab__content">
                        <span class="mdc-tab__icon material-icons" aria-hidden="true">keyboard_arrow_right</span>
                        <span class="mdc-tab__text-label">Other</span>
                    </span>
                    <span class="mdc-tab-indicator">
                        <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
                    </span>
                    <span class="mdc-tab__ripple"></span>
                </button>

            </div>
        </div>
    </div>
</div>

而这个 JS

    const tabBar = mdc.tabBar.MDCTabBar.attachTo(document.querySelector('.mdc-tab-bar'));
    tabBar.listen('MDCTab:interacted', function (event) {
        alert(1);
    });
    document.querySelectorAll('.mdc-tab-bar button')[3].click();
    //tabBar.activateTab(3);

调用单击工作（通过代码或使用鼠标手动），并发出事件并警告“1”。但是我宁愿使用该activateTab功能，但它只会使选项卡处于活动状态，但不会发出事件。

有谁知道这里有什么问题？

Answer 1

该MDCTab:interacted事件在选项卡激活之前发出，这就是使用该activateTab方法时未触发它的原因。MDCTab:interacted实际上是MDC标签栏用来知道要激活哪个标签的。根据您的最终目标，您可能能够通过使用MDCTabBar:activated事件来获得所需的内容，因为它将由activateTab方法触发并在事件详细信息数据中提供已激活选项卡的索引。

const tabBar = mdc.tabBar.MDCTabBar.attachTo(document.querySelector('.mdc-tab-bar'));
const tabs = document.querySelectorAll('.mdc-tab');
tabBar.listen('MDCTabBar:activated', (event) => {
  const tab = tabs[event.detail.index];
  console.log(tab.children[0].children[1].textContent, 'tab activated');
});

tabBar.activateTab(3); // activate "Restriction" tab

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Material Tabs Example</title>
    <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700">
    <link href="https://unpkg.com/material-components-web@latest/dist/material-components-web.min.css" rel="stylesheet">
    <script src="https://unpkg.com/material-components-web@latest/dist/material-components-web.min.js"></script>
  </head>
  <body>
    <div class="mdc-tab-bar" role="tablist">
      <div class="mdc-tab-scroller">
        <div class="mdc-tab-scroller__scroll-area">
          <div class="mdc-tab-scroller__scroll-content">
            <button class="mdc-tab mdc-tab--active" role="tab" aria-selected="true" tabindex="0">
              <span class="mdc-tab__content">
                <span class="mdc-tab__icon material-icons" aria-hidden="true">title</span>
                <span class="mdc-tab__text-label">Name</span>
              </span>
              <span class="mdc-tab-indicator mdc-tab-indicator--active">
                <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
              </span>
              <span class="mdc-tab__ripple"></span>
            </button>
            <button class="mdc-tab" role="tab" aria-selected="false" tabindex="0">
              <span class="mdc-tab__content">
                <span class="mdc-tab__icon material-icons" aria-hidden="true">style</span>
                <span class="mdc-tab__text-label">Tags</span>
              </span>
              <span class="mdc-tab-indicator">
                <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
              </span>
              <span class="mdc-tab__ripple"></span>
            </button>
            <button class="mdc-tab" role="tab" aria-selected="false" tabindex="0">
              <span class="mdc-tab__content">
                <span class="mdc-tab__icon material-icons" aria-hidden="true">favorite</span>
                <span class="mdc-tab__text-label">Status</span>
              </span>
              <span class="mdc-tab-indicator">
                <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
              </span>
              <span class="mdc-tab__ripple"></span>
            </button>
            <button class="mdc-tab" role="tab" aria-selected="false" tabindex="0">
              <span class="mdc-tab__content">
                <span class="mdc-tab__icon material-icons" aria-hidden="true">warning</span>
                <span class="mdc-tab__text-label">Restriction</span>
              </span>
              <span class="mdc-tab-indicator">
                <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
              </span>
              <span class="mdc-tab__ripple"></span>
            </button>
            <button class="mdc-tab" role="tab" aria-selected="false" tabindex="0">
              <span class="mdc-tab__content">
                <span class="mdc-tab__icon material-icons" aria-hidden="true">keyboard_arrow_right</span>
                <span class="mdc-tab__text-label">Other</span>
              </span>
              <span class="mdc-tab-indicator">
                <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
              </span>
              <span class="mdc-tab__ripple"></span>
            </button>
          </div>
        </div>
      </div>
    </div>
  </body>
</html>