touch_events library Null safety
Touch Events - Level 2
- The interface represents a single contact point on a touch-sensitive device. The contact point is commonly a finger or stylus and the device may be a touchscreen or trackpad. [...]
- The interface represents an UIEvent which is sent when the state of contacts with a touch-sensitive surface changes. This surface can be a touch screen or trackpad, for example. The event can describe one or more points of contact with the screen and includes support for detecting movement, addition and removal of contact points, and so forth. [...]
- The interface represents a list of contact points on a touch surface. For example, if the user has three fingers on the touch surface (such as a screen or trackpad), the corresponding object would have one Touch object for each finger, for a total of three entries.