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.
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.
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.
Avoid interfering with systemwide screen-edge gestures. Depending on the device, screen-edge gestures provide access to the Home screen, app switcher, Notification Center, Control Center, and Dock. People rely on these gestures to work in every app. In rare cases, immersive apps like games might require custom screen-edge gestures that take priority over the system's gestures—the first swipe invokes the app-specific gesture and a second swipe invokes the system gesture. This behavior (known as edge protect) should be implemented sparingly, as it makes it harder for people to access the system-level actions. For developer guidance, see the preferredScreenEdgesDeferringSystemGestures() method of UIViewController.
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.
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.
For developer guidance, see UIGestureRecognizer.
People generally expect the following standard gestures to work the same across the system and in every app.