The widget system has been part of Android since the early versions of the operating system. In fact, the widget interface was not updated or improved since Android 4.0. There are a lot of limitations:
- widgets receive a small subset of user interactions: single taps and vertical scroll gestures. Long press and other gestures are not possible for widget apps to detect.
- the system provides information about the dimensions of a widget, but not of its position on the screen
Some launchers even fail to report the dimensions correctly.