B4A Library [Lib] ScrollView2D

Informatix · Jul 4, 2012

Hello,

Does it need a long explanation ? You can scroll in the two directions.

This lib does not work with Android versions < 2.

v1.01:
I fixed a big bug in the original code.
I added the function SmoothScrollTo.

v1.02:
I restarted from a fresh basis because of the many bugs in the original code. I fixed most of them (now, multitouch events and hardware keys are correctly handled) but a few are left and need more work (sometimes the wrong object get the focus and resizing is not perfectly handled). I noticed by the way that the stock scrollview is bugged and does not set the focus correctly if you move your finger very slowly.
Thanks to Erel, I solved the problem with the B4A documentation.
I added a new function: FullScroll.

v1.03:
I fixed all known bugs (including bugs found in ScrollView & HorizontalScrollView);
I added the scrollbars;
I added three new functions:
- ScrollbarsVisibility
- FadingEdges
- GiveFocusToFirstVisible.

v1.1:
I fixed a problem with events that were not fired if declared in a class;
I added two functions: ScrollingIsFinished and DisableTouchEventInterception.

v1.2:
SV2D appears now as a custom view in the designer with all its properties.

v1.3:
I fixed a bug (SV_2 = SV_1 did not work because the inner panel was declared in the wrong class).

Enjoy,
Fred

Informatix · Oct 18, 2016

peacemaker said:
Informatix, pls, see https://www.b4x.com/android/forum/t...-class-tree-and-node.19082/page-4#post-448121
Maybe this trouble is in ScrollView2D lib ?

Impossible to say without a project to reproduce the error.

peacemaker · Oct 18, 2016

Project sample is in the first post: https://www.b4x.com/android/forum/threads/class-treeview-class-tree-and-node.19082/
Possible to check ?

Robert Valentino · Dec 14, 2016

Just tried to upgrade from v1.1 to (v1.2 and v1.3) and now when I try and set the ScrollView2D.Panel <height and width>

Crashes

B4X:

  mGrid_Body_SV2D.Panel.Height = CurOffset  + (mFixedHeight - mGridSpacing) + mGridSize
  mGrid_Body_SV2D.Panel.Width  = CurGridBodyLeft + mGridSize

Error occurred on line: 881 (cGrid)
java.lang.NullPointerException
at anywheresoftware.b4a.objects.ViewWrapper.setHeight(ViewWrapper.java:165)
at com.BOBs.GolfScore.cgrid._showgrid(cgrid.java:739)
at com.BOBs.GolfScore.aplayerscoring._drawscoringscreen(aplayerscoring.java:3967)
at com.BOBs.GolfScore.aplayerscoring._createscreen(aplayerscoring.java:3658)
at com.BOBs.GolfScore.aplayerscoring._precreate(aplayerscoring.java:1031)
at com.BOBs.GolfScore.aplayerscoring._activity_create(aplayerscoring.java:773)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)

If I go back to v1.1 everything is fine.

Can I no longer set the Height and Width in the new versions?

Informatix · Dec 15, 2016

Robert Valentino said:
Can I no longer set the Height and Width in the new versions?

No.
From the demo:

B4X:

Sub btnTransform_Click
...
        sv2d.Panel.Width = 960dip
        sv2d.Panel.Height = sv2d.Height
...
End Sub

Please post a project that reproduces the issue.

boten · Jan 19, 2017

My ScrollView2D's inner panel has labels stacked one below the other.
Each label is of fixed height (lblhgt).

Scrolling vertically (both by slow finger movement AND by fling) can scroll any amount.

What's the best approach to force scroll "by full label height", that is, when a scroll is done - snap VerticalScrollPosition to a integer multiple of lblhgt?

W. Graf · Sep 8, 2017

Hi Informatix!

ScrollView2D is really great! I like it.
I only have one Problem: I added a seekbar on a ScrollView2D. The touch-event of the seekbar is captured by ScrollView2D. So I'm Scrolling the 2D-area, but not the seekbar. Only in 1 of 10 tries, I'm able to scroll the seekbar.
Is there a possibility, that ScrollView2D only ignores the touch-event, if I touch the seekbar?

Thank you!

Informatix · Sep 8, 2017

From the doc:
DisableTouchEventInterception(DisabledAsBoolean)
Prevents the ScrollView2D from intercepting the touch events.

W. Graf · Sep 8, 2017

Thanks for your QUICK(!) answer!!!

If I call ScrollView2D1.DisableTouchEventInterception(True), then nothing changes.
I put this call into the click-event of a button. Both the button and the seekbar is on the ScrollView and both were scrolled by ScrollView. If I click on the button, the function is called, but I still can scroll the ScrollView2D (and I'm not able to scroll the seekbar).

Btw: This call prevents the scroll generally, right? So I will not be able to scroll at all, right?

Informatix · Sep 8, 2017

W. Graf said:
Thanks for your QUICK(!) answer!!!

If I call ScrollView2D1.DisableTouchEventInterception(True), then nothing changes.
I put this call into the click-event of a button. Both the button and the seekbar is on the ScrollView and both were scrolled by ScrollView. If I click on the button, the function is called, but I still can scroll the ScrollView2D (and I'm not able to scroll the seekbar).

Btw: This call prevents the scroll generally, right? So I will not be able to scroll at all, right?

Ah yes you're right. It's for the ScrollView2d parent, not for the children. The only solution is to call something similar in the seekbar code to prevent ScrollView2D from intercepting the touch event.

W. Graf · Sep 8, 2017

I'm afraid, that Seekbar doesn't offer such a function.

Ok, then I will have to think about a new GUI-design for my app. Thanks for your Reply.

Frank660405 · Apr 13, 2018

MANY THANKS!

RichardHirst · Jun 9, 2018

Hello

Please can you tell me if it is possible to Stop the ScrollView2D from moving with code. I see the Enable but not sure what this does.

I want to draw on the canvas while then ScrollView2D remains static, then be able to pan around the panel (which is larger than the screen) using the scroll events etc.

Thank You

Richard

Star-Dust · Jan 8, 2019

@Informatix , Why are you releasing the sources of your libraries?

DonManfred · Jan 8, 2019

Star-Dust said:
Why are you releasing the sources

#324 + #328

Star-Dust · Jan 8, 2019

alirezahassan · Oct 26, 2021

hi all,
Is it possible that Scroll be RTL or LTR?

klaus · Oct 26, 2021

Sorry, I do not understand your question.
ScrollView2D scrolls in both directions.
Of course, if you are on the left edge you can scroll only to the right.
And if you are on the right edge you can scroll only to the left.
Do you have an example showing your problem ?

alirezahassan · Oct 26, 2021

I mean, can the scroll be right when it is created? (If it can be taken with the position code and transferred to a position, it can be fixed.)
In English, scrolling must be done from the left.
In languages like Arabic it must be created from the right.

klaus · Oct 26, 2021

The ScrollView2D class has nothing to do with languages.
You can set the horizontal position at the beginning to any position and of course to the most right position with:
ScrollView2D.HorizontalScrollPosition = xxx

wdegler · Aug 23, 2023

Informatix said:
Hello,

Does it need a long explanation ? You can scroll in the two directions.

This lib does not work with Android versions < 2.

v1.01:
I fixed a big bug in the original code.
I added the function SmoothScrollTo.

v1.02:
I restarted from a fresh basis because of the many bugs in the original code. I fixed most of them (now, multitouch events and hardware keys are correctly handled) but a few are left and need more work (sometimes the wrong object get the focus and resizing is not perfectly handled). I noticed by the way that the stock scrollview is bugged and does not set the focus correctly if you move your finger very slowly.
Thanks to Erel, I solved the problem with the B4A documentation.
I added a new function: FullScroll.

v1.03:
I fixed all known bugs (including bugs found in ScrollView & HorizontalScrollView);
I added the scrollbars;
I added three new functions:
- ScrollbarsVisibility
- FadingEdges
- GiveFocusToFirstVisible.

v1.1:
I fixed a problem with events that were not fired if declared in a class;
I added two functions: ScrollingIsFinished and DisableTouchEventInterception.

v1.2:
SV2D appears now as a custom view in the designer with all its properties.

v1.3:
I fixed a bug (SV_2 = SV_1 did not work because the inner panel was declared in the wrong class).

Enjoy,
Fred

Thank you! This is just what I needed.

My next step is to find out why B4A Bridge cannot parse any of my packages. It worked yesterday.

B4A Library [Lib] ScrollView2D

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