网址：https://developer.apple.com/design/human-interface-guidelines/ios/app-architecture/loading/

作者：苹果公司

译者：泽泽先生 

正文：

When content is loading, a blank or static screen can make it seem like your app is frozen, resulting in confusion and frustration, and potentially causing people to leave your app.

当内容在加载时，一个空白或者静止不动的页面看起来就像被冻住了一样，会让用户觉得困惑和沮丧，也可能会让用户离开你的应用程序。

Make it clear when loading is occurring. At minimum, show an activity spinner that communicates something is happening. Even better, display explicit progress so users can gauge how long they’ll be waiting.

当页面正在加载时，要让这一切看起来是清晰的。至少给用户展示活动列表（告知用户正在加载中...）从而让用户看到反馈，更好的方式是呈现一个清晰的进度条，这样用户就知道还要等待多久。

Show content as soon as possible. Don’t make people wait for content to load before seeing the screen they're expecting. Show the screen immediately, and use placeholder text, graphics, or animations to identify where content isn't available yet. Replace these placeholder elements as the content loads. Whenever possible, preload upcoming content in the background, such as while an animation is playing or the user is navigating a level or menu.

Educate or entertain people to mask loading time. Consider showing hints about gameplay, entertaining video sequences, or interesting placeholder graphics.

尽可能快速展示内容。在用户看到他们期望的内容之前不要让用户去等待内容的加载，立即展示屏幕，并使用占位符文本、图像、或者动画来标识哪些内容尚不可用，再完成内容加载后完成占位符等元素的替换，在任何可能的时候，在后台预加载即将到来的内容，比如在播放动画或浏览菜单时。

教育或者娱乐用户从而掩饰加载的时间，考虑显示关于游戏玩法、有趣的视频或有趣占位符图形的提示。

Customize loading screens. Although standard progress indicators are usually OK, they can sometimes feel out of context. Consider designing a more immersive experience through custom animations and elements that match the style of your app or game.

自定义加载屏幕。即使标准的进度指示通常情况下都是不错的，但某些时候会让人感觉出戏（脱离了上下文），考虑通过自定义动画和元素设计一个更沉浸的体验从而匹配你的应用程序或游戏的风格。

片尾总结：

• 通过进度条等形式及时给用户反馈；

• 通过占位符等形式提前占据未加载内容，从而给用户应用程序正在努力中的感觉；

• 可以通过有趣加载提示，让这一过程更有趣；

• 让加载提示与应用程序整体设计更加一致，更具沉浸感。

未完待续，下一篇《App Architecture_Modality》，敬请期待。