This document discusses multi-touch gestures and the structure of Android apps. It describes common multi-touch gestures like tap, double tap, scroll, flick, pan, long press, pinch, zoom, and rotate. It also outlines the typical structure of Android apps, including text fields, input controls, pickers, radio buttons, switches, toggle buttons, spinners, split action bars, up buttons, action bars, popup menus, share action providers, notification drawers, heads-up notifications, notification areas, and types of dialogs.