I am writing one application which I am performing multi-touch operations. I am able to do the operations up to 5 touches. But I want to get the response for more than 5 touches.
Please guide me how to do it.
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Just wanted to ask if there is any advantage for either using mouse click event or touch tap events, when writing apps for mobiles or tablets (for the iphone especially)?
I know that both of them should work fine, but in term of performance, is anyone better? Are there any things I should be aware of when choosing either?
By the way am using actionscript3 to implement the app.
This is probably the best documentation on Adobe AIR touch support:
http://help.adobe.com/en_US/as3/dev/WSb2ba3b1aad8a27b0-6ffb37601221e58cc29-8000.html
Midway through that page it states:
Note: Listening for touch and gesture events can consume a significant amount of processing resources (equivalent to rendering several frames per second), depending on the computing device and operating system. It is often better to use mouse events when you do not actually need the extra functionality provided by touch or gestures.
The only benefit of touch, I would think, would be multi-touch. The TouchEvent has a touchPointID which allows you to track the movement of each touch point. If you don't care about multi-touch, it sounds like Mouse Events would be the way to go.
Excellent question! Tap events are "technically" slower as they monitor multiple input points. If your only concerned with a single touch input, the standard mouse event system is just fine. For touch events, there's a couple objects being created per listener to assist in handling the multitouch functionality (however this is close to a tiny fractional ms loss in performance).
i think that the touchEvent is better than mouseevent when implement the app on tablets!i try it many times!you can have a test
I noticed a crash in our application, and traced it back to an interesting problem.
I have a UIVIew that is 320x480. It overrides touchesEnded:withEvent: and checks the touch location to do some logic.
The interesting thing is that on ipad (only) we were receiving touch events with an X range from 0 to 320... inclusive. That's the important bit.
How does a view with 320 pixels across have a potential for 321 different touch locations? Is this a known bug? Is there some reason for it?
To replicate this, run your iphone app on an ipad (in the compatibility emulator mode), touch down in a view and slide your finger off one side or the other. You'll receive a touch event with an x value of 0 or 320. You can do this for Y too. I can't replicate this on an iphone.
A touch on a capacitive touch display isn't physically a single pixel, more likely a fuzzy noisy blob with only a probable location and diameter. So this could be a result of some post processing adjustments between the analog measurements and the event handler.
Or this could also just be a bug. Go ahead and report it to Apple.
I have developed a test for iPod/iPhone (with MonoTouch if that is relevant) that measures reaction time. But I need to take into consideration the time between touching the screen and actual triggering of the button event. Is there any documentation of that?
It's already very hard to almost impossible to get predictable interrupt latency on real time operating systems.
But on the iPhone? Imho impossible. A capacitive touchscreen is not optimal to get results that are exactly the same for each body and location. And if mail.app decides to poll for emails just at the moment you'll touch the screen there will be a bigger delay.
But to make one thing clear, we are speaking about some micro seconds or even less than that.
If you want accurate results you shouldn't use an iPhone. But I guess your app will be some kind of game, so nobody cares if your result is 0.01 seconds off. But I wouldn't show results as 0.381829191 seconds, that fakes accuracy you'll never get on any smartphone.
What is the lowest reaction time you got in your app?
The time between an actual touch and the system registering it will be negligable.
One key thing: if you are detecting the press using touch events like touchUpInside, consider using the touchesDownInside event because touchesUpInside, will not fire until the user's finger leaves the screen.
Anyone know if it is yet possible to detect the touch shape? Maybe through getting the raw touchscreen data?
I found this question/answer here: How to get raw touchscreen data?
That mentions GSEvent, but it is quite old.
I'd like to try to get a rough calculation of the pressure of the touch by its shape/area, but of course UITouch only gives a calculated point.
Yes, raw touch data is contained in the GSEventRecord object, particularly what you are looking for is the pathMajorRadius property on GSPathInfo, which gives the major radious on the tap. This is a rough estimate of the pressure, but take into account big/small fingers give also different measures.
Watch out for the pathPressure property also in GSPathInfo, it does NOT contain the pressure. It always contains 1, capacitive screens (like the iPad's or IPhone's) do not measure pressure at all.
If you are planning submitting your app in the app store, you won't be able to do it if you include access to private frameworks (like in this case, GSEvent.h in the GraphicServices framework). But what you need to do is catch every UIEvent in the sendEvent method of your subclassed UIApplication, then use the methods in
https://github.com/kennytm/iphone-private-frameworks/blob/master/GraphicsServices/GSEvent.h
to get the information of the GSEvent.
I would like to develop a multi-touch (up to 8 fingers) application for iPhone/iPod Touch.
But during testing on my 1st gen iPod Touch once I put the 6th finger weird things started to happen.
I don't get Touch Began for the 6th finger nor Touch Ended/Cancelled for the first 5 fingers.
Do you know of any workaround for this?
Does it behave the same on your iPhones/iPods?
Would it work on G1 on Android?
Thanks
You can't. If you need that functionality you should file a feature request with Apple, but I suspect it is a hardware limitation that in the screen controller.
I would guess that 5 fingers is the upper limit. I imagine the engineers assumed most people have two hands with five fingers per hand, so the average person holding the phone in one hand only has five fingers to work with.
Holding your phone with just your thumbs seems precarious at best, so using it as a trumpet seems unlikely.
Just a note: the iPad can recognize 11 touches.
I have no idea if it would work on Android, but there will be an upper limit for the number of simultaneous touches that you can have. Future iPhones/iPods may up that limit, but it's not defined and you shouldn't assume that you can handle more than a few realistically.
As far as Android is concerned, right now I don't believe there's multi-touch support due to Google having removed support for it as per Apple's request.
The system is only capable of tracking 5 finger touches at once. You should only ever get 5 touch events at the same time, I think anything over that is ignored.
You're probably seeing odd behavior because its not consistently picking the same 5 out of 8 fingers to report touch events on.