吸引用户采取行动

借助 Action 对象，您可以将交互行为构建到 Google Workspace 插件中。它们定义了当用户与插件界面中的某个 widget（例如按钮）互动时会发生的情况。

使用 widget 处理程序函数， 这也定义了触发操作的条件。触发时，该操作会执行指定的回调函数。系统会向该回调函数传递 事件对象，它包含 有关用户客户端互动情况的信息您必须实现回调函数，并使其返回特定的响应对象。

例如，假设您希望某个按钮在被点击时构建并显示新卡片。为此，您必须创建一个新的按钮微件，并使用按钮微件处理程序函数 setOnClickAction(action) 设置卡片构建 Action。您定义的 Action 会指定一个在用户点击按钮时执行的 Apps 脚本回调函数。在这种情况下，您需要实现回调函数来构建所需的卡片，并返回 ActionResponse 对象。响应对象会告知插件向卡片显示回调 函数。

本页介绍了您可以在插件中添加的 Drive 专用微件操作。

促进互动

扩展云端硬盘的 Google Workspace 插件可以包含一个额外的云端硬盘专用微件操作。此操作需要关联的操作回调函数返回专用响应对象：

已尝试执行操作	回调函数应返回
请求对所选文件的文件访问权限	DriveItemsSelectedActionResponse

要使用这些 widget 操作和响应对象，必须设置以下 必须为 true：

• 当用户选择一个或多个云端硬盘内容时，系统会触发此操作。
• 该插件在其清单中包含 https://www.googleapis.com/auth/drive.file 云端硬盘范围。

请求对所选文件的文件访问权限

以下示例展示了如何为 Google Cloud 构建上下文接口， 用户选择一项或多项云端硬盘内容时触发的云端硬盘。该示例会测试每个项，以确定是否已向该插件授予访问权限；如果未授予，则使用 DriveItemsSelectedActionResponse 对象向用户请求该权限。针对 该插件将显示该内容的云端硬盘配额使用情况。

/**
 * Build a simple card that checks selected items' quota usage. Checking
 * quota usage requires user-permissions, so this add-on provides a button
 * to request `drive.file` scope for items the add-on doesn't yet have
 * permission to access.
 *
 * @param e The event object passed containing contextual information about
 *    the Drive items selected.
 * @return {Card}
 */
function onDriveItemsSelected(e) {
  var builder =  CardService.newCardBuilder();

  // For each item the user has selected in Drive, display either its
  // quota information or a button that allows the user to provide
  // permission to access that file to retrieve its quota details.
  e['drive']['selectedItems'].forEach(
    function(item){
      var cardSection = CardService.newCardSection()
          .setHeader(item['title']);

      // This add-on uses the recommended, limited-permission `drive.file`
      // scope to get granular per-file access permissions.
      // See: https://developers.google.com/drive/api/v2/about-auth
      if (item['addonHasFileScopePermission']) {
        // If the add-on has access permission, read and display its
        // quota.
        cardSection.addWidget(
          CardService.newTextParagraph().setText(
              "This file takes up: " + getQuotaBytesUsed(item['id'])));
      } else {
        // If the add-on does not have access permission, add a button
        // that allows the user to provide that permission on a per-file
        // basis.
        cardSection.addWidget(
          CardService.newTextParagraph().setText(
              "The add-on needs permission to access this file's quota."));

        var buttonAction = CardService.newAction()
          .setFunctionName("onRequestFileScopeButtonClicked")
          .setParameters({id: item.id});

        var button = CardService.newTextButton()
          .setText("Request permission")
          .setOnClickAction(buttonAction);

        cardSection.addWidget(button);
      }

      builder.addSection(cardSection);
    });

  return builder.build();
}

/**
 * Callback function for a button action. Instructs Drive to display a
 * permissions dialog to the user, requesting `drive.file` scope for a
 * specific item on behalf of this add-on.
 *
 * @param {Object} e The parameters object that contains the item's
 *   Drive ID.
 * @return {DriveItemsSelectedActionResponse}
 */
function onRequestFileScopeButtonClicked (e) {
  var idToRequest = e.parameters.id;
  return CardService.newDriveItemsSelectedActionResponseBuilder()
      .requestFileScope(idToRequest).build();
}

/**
 * Use the Advanced Drive Service
 * (See https://developers.google.com/apps-script/advanced/drive),
 * with `drive.file` scope permissions to request the quota usage of a
 * specific Drive item.
 *
 * @param {string} itemId The ID of the item to check.
 * @return {string} A description of the item's quota usage, in bytes.
 */
function getQuotaBytesUsed(itemId) {
  try {
    return Drive.Files.get(itemId,{fields: "quotaBytesUsed"})
        .quotaBytesUsed + " bytes";
  } catch (e) {
    return "Error fetching how much quota this item uses. Error: " + e;
  }
}