本文是 iOS Human Interface Guidelines 中 Design Principles 的中文译文。纯手工翻译，加深自己理解。
Aesthetic Integrity
Aesthetic integrity represents how well an app’s appearance and behavior integrate with its function. For example, an app that helps people perform a serious task can keep them focused by using subtle, unobtrusive graphics, standard controls, and predictable behaviors. On the other hand, an immersive app, such as a game, can deliver a captivating appearance that promises fun and excitement, while encouraging discovery.
整体美学
整体美学表示了一个应用的呈现和功能需要融为一体。例如，用于完成正式工作的应用，可以通过低调精妙的图片、标准化的控件、可预测的交互行为，帮助人们聚焦在工作本身。另一方面，提供沉浸式体验的应用，例如游戏，在鼓励用户探索的同时，会提供有吸引力的外观，从而带来快乐和刺激。
Consistency
A consistent app implements familiar standards and paradigms by using system-provided interface elements, well-known icons, standard text styles, and uniform terminology. The app incorporates features and behaviors in ways people expect.
一致性
风格一致性是指，通过使用系统提供的接口、熟悉的图标、标准的文本样式、统一的用辞，来实现熟悉的标准和样式。应用中包含符合用户期望的功能和行为。
Direct Manipulation
The direct manipulation of onscreen content engages people and facilitates understanding. Users experience direct manipulation when they rotate the device or use gestures to affect onscreen content. Through direct manipulation, they can see the immediate, visible results of their actions.
直接操控
直接操控屏幕上的内容，可以帮助人们进行理解。当用户旋转设备或者使用手势来影响屏幕内容时，用户可以体验到直接操控的感觉，他们可以立即看到自己动作所带来的可视化结果。
Feedback
Feedback acknowledges actions and shows results to keep people informed. The built-in iOS apps provide perceptible feedback in response to every user action. Interactive elements are highlighted briefly when tapped, progress indicators communicate the status of long-running operations, and animation and sound help clarify the results of actions.
反馈
反馈可以确认操作，使人们感知到结果。iOS自带应用提供可以感知的反馈，来响应每个用户的行动。这些有助于说明用户行动的结果：交互元素点击瞬间高亮显示、进度指示来显示耗时操作的状态、动画和音效。
Metaphors
People learn more quickly when an app’s virtual objects and actions are metaphors for familiar experiences—whether rooted in the real or digital world. Metaphors work well in iOS because people physically interact with the screen. They move views out of the way to expose content beneath. They drag and swipe content. They toggle switches, move sliders, and scroll through picker values. They even flick through pages of books and magazines.
隐喻
当应用中的虚拟对象和操作，能用熟悉的体验来形象比喻时，无论这些体验是基于现实世界或者数字世界，用户会很快理解如何使用。隐喻在iOS上非常有效，因为用户通过屏幕来进行互动。用户移动视图来查看更多内容、拖曳和滑动内容、点击开关、移动滑条、滚动滚盘、快速翻页。
User Control
Throughout iOS, people—not apps—are in control. An app can suggest a course of action or warn about dangerous consequences, but it’s usually a mistake for the app to take over the decision-making. The best apps find the correct balance between enabling users and avoiding unwanted outcomes. An app can make people feel like they’re in control by keeping interactive elements familiar and predictable, confirming destructive actions, and making it easy to cancel operations, even when they’re already underway.
用户控制
在iOS中，是人来进行控制，而不是应用。应用可以建议一系列的操作，或者对危险的后果进行警告，但是让应用来做决定通常都是错误的。最好的应用在用户操作和避免错误结果之间进行平衡。通过使用熟悉和行为可预测的交互元素、对重要操作进行确认、更容易取消操作即便已在执行中，应用就可以让人感觉到他们在进行控制。
参考：
[1] iOS Design Principles
