Thank you for that nice example.
Is there a way to use it with a list with selectable items?
I am working with such a list and it happens of course a selection on mouseUp when i want just scroll. how could i implement a logic that avoids that so a line gets selected just when i tip on it but not when scrolling. Thanks.

Hi TG,

from your comment I take it that you have already implemented the functionality but are now just wondering how to handle the mouseUp message.

You could use the mouseLoc to get the X,Y location of the mouse in the mouseDown and then mouseUp handlers and then test if there is a significant distance between these locations. If there is, then you have a scroll.

Measuring the X or Y shift may be sufficient, if not, use Pythagoras to get the distance in any direction.

Kind Regards,

Hanson

Thanks so far :-)
I've been trying for a while now to use that principle on a datagrid with form-style (rather than on a simple field as in the example above). However, I couldn't make it work...
Could you please show us / give an example how to use the mobile scroller in a datagrid? I've searched the forum all morning but couldn't find a working example...

Many thanks in advance

Kevin

Hi Kevin,

that is an interesting concept.
Not quite sure how well this would work as the datagrid manages its own scrolling. In effect you could have two sets of scrollers to contend with.

I am assuming that you are trying to utilize the dynamic layout configuration of the datagrid but at the same time want to provide a more native scrolling experience.

My suggestion would be to make the datagrid as big as you need it to be so you can fit all of the data on one page, that way removing its own scrollers. The result could then be added to a group that is controlled by the native mobile scrollers.

I have not tested this, but it would be the approach I would initially consider.

Kind Regards,

Hanson

One of my problems is the text is not fixed. I want to display a push notice in the field. Not a problem, really. But since adding the scroller above, the problem comes with different screen sizes and orientations. My layouts got weird after adding the scroller. I got the layout fixed, but only for portrait. After that the touch scroller fails now.

I am a beginner developing for Android (iPhone later if I ever get this app to work). Any help is appreciated. Thank you & Cheers!

P.S. Haven't been to Scotland since 2001, I miss it there.

Hi Daniel,

I am not sure what you mean when you say that your layouts got weird.
Can you please provide some more details one what exactly is not working for you.

Kind Regards,

Hanson

Is there any reason the field needs to be in a group?

local sScrollerID
on preOpenCard
local tScrollerRect,tContentRect
if environment() is not "mobile" then exit preOpenCard
mobileControlCreate "scroller", "loremScroll"
put the result into sScrollerID
put the rect of fld "scrollme" into tScrollerRect
put the topleft of fld "scrollMe" & "," & the right of fld "scrollme"&","&( the top of fld "scrollme" + the formattedHeight of fld "scrollme") into tContentRect
mobileControlSet "loremScroll", "rect", tScrollerRect
mobileControlSet "loremScroll", "contentRect", tContentRect
mobileControlSet "loremScroll", "visible", true
mobileControlSet "loremScroll", "scrollingEnabled", true
mobileControlSet "loremScroll", "vIndicator", true
mobileControlSet "loremScroll", "vscroll", 0
end preOpenCard

on scrollerDidScroll hOffset, vOffset
// When the user scrolls move the displayed content
set the vScroll of fld "scrollMe" to vOffset
end scrollerDidScroll

Seems to work ok?

Hi Malte

No, the field doesn't need to be in a group. Your method will work equally well.

Kind regards

Elanor

Good example, but there is an error in the code.

If you move the group down the card and with fewer lines of text, the scroller either doesn't scroll or only partially scrolls.

The problem is the line:

put the left of field "lorem",the top of field "lorem",the right of field "lorem",the formattedHeight of field "lorem" into tContentRect

A rect is defined by left,top,right,bottom, but the formattedHeight property returns the height not the bottom of an object.

With the group at the top of the card the formattedHeight property is almost the same value as bottom and the example works, but as the group is moved down the card the 2 values diverge and the scroller behaviour is more erractic.

With the group lower down the card and using fewer lines of text, by using formattedHeight alone for the value of bottom it is possible for the rect value for bottom to be less than the value for top, and the scroller will no longer work.

The line should read:

put the left of field "lorem",the top of field "lorem",the right of field "lorem",the top of field "lorem" + the formattedHeight of field "lorem" into tContentRect

Dear Steve Bennet,

Thanks for bringing that error to our attention. I have correct the code in the lesson.

Kind regards

Elanor

Hi

Whats the purpose of "put the result into sScrollerID"? sScrollerID doesn't get used again in the example. Is it to provide an ID that can subsequently be used with mobileControlDelete? If that's the case, wouldn't mobileControlDelete "loremScroll" achieve the same?

Regards

Kim

Hi Kim

You are right, it is not needed. The control can be referred to by name. When these native controls were first added they could only be referred to by ID and I think this part of the lesson is a remnant of that old requirement.

I have updated the lesson and attached stack to refer to the scroller by name throughout.

Thanks for bringing this to our attention.

Kind regards

Elanor

Would be nice to add how to scroll by script to the end or to a specific line

Hi Trevix

I have added another section to the end of the lesson that explains how to do this.

I hope that helps.

Elanor

Thanks for this lesson and the comments, they helped to make the scrolling beter than it was and I learned some new stuff :), however there are still some things I like to tune and I can't seem to figure out how to do them.
The content bounces at the bottom but not at the top.
When I arrive at the bottom and drag upwards this only works for a certain distance. When I drag it up further the content stops moving and when I release there is a short period in which nothing happens, it seems to freeze, it feels a bit off. When a smaller movement is made it works fine though.
Any help is welcome and I hope the descriptions make sense.

Hi Freek,

If you have "canBounce" set to true it should work, and I am not sure what the issue with dragging from the bottom could be. Could you let us know if you see this in the attached example stack and what OS and device you are using so we can take a look.

Thank you.

Kind regards

Elanor

Hi Elanor,

Thanks for your reply.
I'm using a MacBook Air with Mojave 10.14.4; LiveCode Indy 9.6.0 (dp 3); Xcode 11.3.1; and a iPhone 11 pro Max 13.3 simulator. Hope that helps.
With the example stack the same things happen, also with
mobileControlSet "loremScroll", "canBounce", true
The bottom does bounce, but the top doesn't.
With regard to the dragging from the bottom:
I'm going to do my best in putting it into words, but I don't know the proper terms. For example, when using a touchpad from a Mac, when one is within the boundaries of a page and one moves its fingers from one edge of the mousepad to the edge on the other side of the mousepad, that corresponds to roughly a scroll with the size of the screen. When one is at the boundary of the page and makes the same movement on the mousepad, the corresponding movement on the screen is about 1/5 - 1/10 of the screen.
In the simulator this does work for a certain amount of drag, but it stops dragging before arriving at the boundary.

These are some minor details, and the way of scrolling in my app has improved so I'm glad about that. However for future apps I rather have small details right all the time, than having a small "mistake" each time.

If I somehow find out where the issue lies or how to solve it, I"ll let you guys now and I would be grateful if you beat me to it :).

Ciaociao!

Hi,

I think you are probably experiencing this bug

https://quality.livecode.com/show_bug.cgi?id=21456

There are some workarounds suggested in the discussion on the bug report.

I hope that helps,

Kind regards

Elanor

How do you set the vscroll of a native scroller when the field it is connected to is not at the beginning of the text?

This code always sets the vscroll to 0:
mobileControlSet "loremScroll", "vscroll", 0

So if you add a second card to the example stack, scroll half-way down the text, switch to the second card) which destroys the scoller) and switch back to the first card (which recreates the scroller), the scroller will NOT let you scroll back up because the present text position is set to 0.

So I saved the vscroll on "closeCard" before the scroller was deleted, and then assigned it to the scroller when it is recreated with:
mobileControlSet "loremScroll", "vscroll", savedScrollValue
But the mobile scroller is still set to 0.

If I run:
mobileControlGet("loremScroll", "vscroll")
after I set the value, it returns that the scroller is set to the value of "savedScrollValue". But when you try to scroll, you see that the scroller is at 0.

I've tried:
mobileControlSet "loremScroll", "vscroll", savedScrollValue
I've tried:
set the vScroll of group "scrollArea" to savedScrollValue
I've tried setting the vscroll of the field "lorem", nothing works. The mobile scroller always starts at 0 no matter what I assign it to. How can I tell the scroller that we not starting at vscroll = 0?

Hello Jeff,

What you describe is a known issue. See https://quality.livecode.com/show_bug.cgi?id=22453 for more details and how to work this around. Short answer: add a "wait 0 milliseconds " just before mobileControlSet "loremScroll", "vscroll", savedScrollValue

Kind regards,
Panos

THANK YOU! I don't think I ever would have figured that out myself. :-)

I'm sorry my "googling" of the issue didn't pull up the bug. I so appreciate the quick response.

Jeff