Gestures
People interact with an iOS device by performing gestures on the touchscreen. These gestures elicit a close personal connection with content and enhance the sense of direct manipulation of onscreen objects. People generally expect the following standard gestures to work the same across the system and in every app.
用户通过手势在触摸屏上与iOS设备交互。这些手势引起一个与内容的人性化连接，增强直接操作屏幕对象的感觉。用户一般期望在整个系统和每个app中以下标准手势表现一致。
Tap.Activates a control or selects an item.
轻巧。激活一个控制或者选择一个item。
Drag.Moves an element from side-to-side or drags an element across the screen.
拖拽。把一个元素从一端移动到另一端或者跨屏幕移动元素。
Flick.Scrolls or pans quickly.
轻弹。很快地滚动或移动。
Swipe.When performed with one finger, returns to the previous screen, reveals the hidden view in a split view controller, reveals the Delete button in a table-view row, or reveals actions in a peek. When performed with four fingers on an iPad, switches between apps.
滑动。当使用一个手指滑动，回到之前的屏幕，显示在分割视图控制器的隐藏视图，显示一个table视图列上的删除按钮，或者显示peek中的操作。当使用4个手指在iPad上操作时，会在app之间转换。
Double tap.Zooms in and centers content or an image, or zooms out if already zoomed in.
双击。放大和居中内容或图片，或者如果已经放大过了则缩小。
Pinch.Zooms in when pinching outward, zooms out when pinching inward.
捏。当向外捏时放大，当向里捏时缩小。
Touch and hold.When performed in editable or selectable text, displays a magnified view for cursor positioning. When performed in certain views, such as a collection view, enters a mode that allows items to be rearranged.
持续按住。当在可编辑或选择的文本里执行操作时，为光标停放的地方显示一个放大的视图。当在特定的视图执行时，例如集合view，进入一个模式，允许item可以重新被排列。
Shake.Initiates undo or redo.
摇动。激活撤销或重做。
As a general rule, use standard gestures.People are familiar with the standard gestures and don’t appreciate being forced to learn different ways to do the same thing. In games and other immersive apps, custom gestures can be a fun part of the experience. In other apps, it’s best to use standard gestures so extra effort isn’t needed to discover or remember them.
尽量使用标准手势。用户熟悉标准手势，不欣赏被强迫学习一种不同的方式去做同样的事。在游戏和其他沉浸式app中，定制的手势可以成为体验的有趣部分。在其他app，最好还是使用标准手势。
Don’t block systemwide gestures.In addition to the standard gestures, some additional gestures invoke systemwide actions, such as revealing Control Center or Notification Center. People rely on these gestures to work in every app.
不要阻塞系统范围的手势。除了标准手势，一些额外的手势调用系统范围操作，例如显示控制中心或者通知中心。用户希望这些手势在所有app都能用。
Avoid using standard gestures to perform nonstandard actions.Unless your app is a game in active gameplay, redefining the meaning of standard gestures leads to confusion and complexity.
避免使用标准手势执行非标准操作。除非你的app是一款游戏，重新定义标准手势的意义会带来困惑和复杂性。
Offer shortcut gestures to supplement, not replace, interface-based navigation and actions.Whenever possible, offer a simple, visible way to navigate or perform an action, even if it means an extra tap or two. Many system apps include a navigation bar that provides a clear, tappable button back to the previous screen. But users can also navigate back by swiping from the side of the screen. On iPad, people can exit to the Home screen by pressing the Home button, or by using a four-finger pinching gesture.
提供便捷手势来提供，而不是替代，基于界面的导航和操作。如果有可能，提供一个简单，可视化的方式来导航或者执行一个操作，即使它意味着一个额外的一两下敲击。许多系统app包括一个导航栏来提供一个清晰的，可敲击的按钮来回到上一个屏幕。但是用户也可以通过在屏幕边缘滑动来导航回去。在iPad，用户可以通过Home键回到主屏幕，或者用4个手指捏的手势。
Use multifinger gestures to enhance the experience of some apps.Although gestures involving multiple fingers at once aren’t appropriate for every app, they can enrich the experience in some apps, such as games and drawing apps. For example, a game might include multiple onscreen controls, such as a joystick and firing buttons, that can be operated simultaneously.
一些app可以使用多手指手势来增强体验。尽管多手指手势不是对所有应用都合适，在一些app中它们可以增强体验，例如游戏和绘画app。例如，一个游戏可能包括多点屏幕控制，例如一个遥感和开火按钮，可以被同时操作。
https://developer.apple.com/ios/human-interface-guidelines/interaction/gestures/
