Another handy trick used in GUI toolkits is to introduce a "clicked" event created by the toolkit. So simple apps don't need to track button states, only listen for the 'clicked' event and ignore all other events. So a button might receive any of these sequences of events:
press -> appearance changes to depressed press, release, clicked -> appearance resets and action triggered press, cancelled -> appearance resets release -> nothing happens but typically an app only really needs to act on 'clicked'. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to mir in Ubuntu. https://bugs.launchpad.net/bugs/1547864 Title: libinput doesn't handle EV_KEY event with a value of 255 (BUTTON_CANCLED), to support Android home buttons Status in Mir: Triaged Status in libinput package in Ubuntu: New Status in mir package in Ubuntu: Triaged Bug description: I port Ubuntu Touch to LG L90 Dual. When I press a button below the screen (it's the touch button and is part of the touch screen), then slide the finger up, a letter will repeatedly appear in any text field selected (for instance, if the button is a menu button, letter 'e' will appear repeatedly). Using evtest with the touch screen device, I can see what happened: Event: time 75.605520, type 1 (EV_KEY), code 139 (KEY_MENU), value 1 Event: time 75.605525, -------------- EV_SYN ------------ Event: time 75.707065, type 1 (EV_KEY), code 139 (KEY_MENU), value 255 (See the full log here: http://paste.ubuntu.com/15112114/) When I place the finger down, touch screen will send an event with type 1 (EV_KEY), code 139 (KEY_MENU), and value 1, indicating that the button is placed. And when I move the finger away from the button, touch screen will send an event with type 1 (EV_KEY), code 139 (KEY_MENU), and value 255. Digging in kernel code reveals that this is defined as "BUTTON_CANCLED". Looking in libevent code, it seems that it always assume that anything that is not 0 will be considered as pressed, which makes it looks like the button is hold. To manage notifications about this bug go to: https://bugs.launchpad.net/mir/+bug/1547864/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
