![]() ![]() In order to identify the index of the pointer that triggered the event, the getActionIndex() callback method of the MotionEvent object must be called. In a multi-touch scenario, pointers begin and end with event actions of type ACTION_POINTER_UP and ACTION_POINTER_DOWN respectively. When more than one touch is performed simultaneously on a view, the touches are referred to as pointers. Any motion of the touch between the ACTION_DOWN and ACTION_UP events will be represented by ACTION_MOVE events. When that touch is lifted from the screen, an ACTION_UP event is generated. When the first touch on a view occurs, the MotionEvent object will contain an action type of ACTION_DOWN together with the coordinates of the touch. The type of action associated with an event can be obtained by making a call to the getActionMasked() method of the MotionEvent object which was passed through to the onTouch() callback method. The topic of identifying distinct gestures will be covered in the next chapter.Īn important aspect of touch event handling involves being able to identify the type of action performed by the user. The objective of this chapter is to highlight the handling of touches that involve motion and to explore the concept of intercepting multiple concurrent touches. Consider, for example, that a horizontal swipe is typically used to turn the page of an eBook, or how a pinching motion can be used to zoom in and out of an image displayed on the screen. Touches can also be interpreted by an application as a gesture. Touches can, of course, be dynamic as the user slides one or more points of contact across the surface of the screen. Nor are touches limited to a single point on the device display. Android multitouch android#Most Android devices can, for example, detect more than one touch at a time. There is, however, much more to touch event handling than responding to a single finger tap on a view object. The previous chapter introduced the mechanism by which a touch on the screen translates into an action within a running Android application. Most Android based devices use a touch screen as the primary interface between user and device. Purchase the fully updated Android Studio Chipmunk Edition of this publication in eBook ($29.99) or Print ($46.99) formatĪndroid Studio Chipmunk Essentials - Java Edition Print and eBook (PDF) editions contain 94 chapters and over 800 pages soon.You are currently reading the Android Studio 1.x - Android 5 Edition of this book. Olli, if you want to start glancing at this, I'm hoping to have it up for review. Hopefully not have to dig into the maps source to hard. Try to add some more comments so its all not too mysterious, and write some more tests to make sure mouse events are being prevented correctly, etc. Get rid of some of the useless logging I have scattered around. So I'm going to plug away at it for another day. >diff -git a/content/base/src/nsContentUtils.cpp b/content/base/src/nsContentUtils.cpp Android multitouch plus#I know this current implementation isn't perfect, but wanted feedback on the approach, plus any big hairy things you wanted to bring up.Ĭomment on attachment 540074 So I've added a gCaptureTouchList hashtable in presshell to do that. In order to get things like changed and targetTouches correct, we need to cache information about the previous events somewhere. Changed reflects touches that are different in this event, and target is touches that were originally targetted at this target. Every touchevent has a touches, changedTouches, and targetTouches attribute. Main question I wanted feedback on relates to caching. I realise the spec isn't exactly clear on all of this, and we will likely need to compare more with Apple, Google, Opera, etc implementations in order to make these things correct, but wanted to keep moving here as well. But I think I'm at the point where getting some feedback would be helpful. I still needs to finish up things like event targeting (both firing the touch events on multiple targets if necessary, and setting targetTouches correctly on touch events), and preventing mouse events when preventDefault is called. This works to fire off multi-touch events from the Android to the parent process, but isn't "done" yet. ![]()
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