How to implement kinetic scrolling?

[svdwal]

I have just upgraded my N97 to the v20 firmware , which implements kinetic scrolling in apps. I did indeed see kinetic scrolling working fine in Web, but it doesn't work automatically in my own app, neither in system listboxes, nor in my own view with it's own CEikScrollBarFrame.

Worse, scrolling, i.e dragging the scrollbars, in my listboxes has stopped working.

So I would like to know how to get kinetic scrolling working, and what I need to to to make sure that it also works for standard listboxes.

This is for apps developed on the generic S60 5th ed sdk. I do not use the N97 plugin as I like to keep my code as device-independent as possible, and that is already hard enough at this time.

An update: I found now that kinetic scrolling works when the listbox is a child of a CAknView-hosted container, but not when the listbox is a child of a plain CCoeControl. The code for creating the listbox is the same, and both listboxex are CAknSingleGraphicStyleListBoxes.

[svdwal]

I have just upgraded my N97 to the v20 firmware , which implements kinetic scrolling in apps. I did indeed see kinetic scrolling working fine in Web, but it doesn't work automatically in my own app, neither in system listboxes, nor in my own view with it's own CEikScrollBarFrame.

[knip]

An update: I found now that kinetic scrolling works when the listbox is a child of a CAknView-hosted container, but not when the listbox is a child of a plain CCoeControl. The code for creating the listbox is the same, and both listboxex are CAknSingleGraphicStyleListBoxes.

In case anybody is interested, the problem was that the listbox in the container was not ActivateL()'ed, due to it being destroyed and recreated depending on the orientation (one kind of listbox in portrait mode, and another kind in landscape mode). This worked fine before kinetic scrolling was implemented, but now it doesn't anymore.

The problem with getting kinetic scrolling to work for my own custom view is still there.

I have done some hacking (overriding the AppUI's HandleWSEventL() to display what events are being sent), and it appears that kinetic scrolling is implemented by the system by sending drag events until scrolling has stopped. In ohter words, EButton1Up is not send as soon as you lift your finger, but later. It looks to your code as if the user is dragging it's finger in such a way that it is moving slower and slower and that the finger at some point stops. This should indeed mean that all controls will automatically support kinetic scrolling, but I would like to know if there are other issues involved, as I don't see much kinetic "dragging" happening in my custom view, ie it appears as if I get a EButton1Up event as soon as I really lift my finger. Are there things like window sizes and/or CCoeControl sizes to be be specified that are bigger than the screen or does the system expect some specific calls to be made (like RDrawableWindow::Scroll()).

[ralle@envicon.de]

The solution is simple, if you have a look at the following Android classes (and port it):

Take a basic scroller class Scroller:
http://www.netmite.com/android/mydro.../Scroller.java

that use one of the following interpolaters:
base:
http://www.netmite.com/android/mydro...erpolator.java

specific:
http://www.netmite.com/android/mydro...erpolator.java
http://www.netmite.com/android/mydro...erpolator.java

I personal use a CPeriod for the scroller animation in my custom control, and request the Scroller class for the new position (using CDecelerateInterpolator in SCROLL_MODE) and move to it. Result is very smooth.

kindly regards,

[svdwal]

Adding my own kinetic scrolling code is absolutely not a solution.

As you should be able to see from my description of the events being delivered, you cannot see that the pen up event is a real one (when I lift my finger from the screen) or a "fake" one (delivered after the kinetic scroller has decided it is time to stop scrolling). Assuming the kinetic scroller will never work for my control is one of those assumptions that will create an endless number of user problem reports as soon as Nokia decides to do something different in a new firmware version.

[r_d_jackson]

I am currently tryign to do exactly the same thing and running into similar problems.
If you get it working then please let me know. Anything I find out I'll post here.
I'm actually using list boxes derived form CEikTextlistBox so there may be some differences.

[nash00cu]

Search about CAknPhysiscs, I don't think is public, but if you get lucky it will do the trick for you.

[ltomuta]

Search about CAknPhysiscs, I don't think is public, but if you get lucky it will do the trick for you.

If you don't think the class is public then maybe you should think twice about even mentioning it. Luck has nothing to do with accessing and using an API.

As usual for non-SDK features a support request, eventually followed by API Partnering, will give the correct solution for any problem.

[r_d_jackson]

Hi, I managed to get this working with a custom CEikTextListBox.
What I found was you need to activate (as already mentioned)
Have to display the scrollbars - not figured out how to display just when flicking just yet but If I turn the scrollbars off then the flick has no effect.
There are additional apis in the N97 sdk which may help but I avoided using them.

[xlazom00]

go trought symbian web browser
http://developer.symbian.org/oss/FCL..._gesturehelper

Kinetic scrolling is alreaady implement in it
And you can simply add bounce effect