Gadtools example with resizable listview.

I want to get rid of a problem in my project using gadtools. It has appeared with AOS4:
Resizing a window with a listview gives a annoying flashing of the listview content.

To better identify the problem i am looking after working programs using Gadtools having such windows and listview, preferrably with source and simple.

Almost all OS2.04 programs did use gadtools , i guess some of them can be foudn that are simple and with source.

OK i found http://thomas-rapp.homepage.t-online.de/examples/lv.c

and can start from there.

This example does not have a sizing gadget. Actually I never put a sizing gadget into a window when working with GadTools. I layout the gadgets and calculate the needed space and then open the window with fixed size.

The problem with GadTools is that existing gadgets cannot be changed after they were created. So in order to change the window size you have do destroy and recreate the entire GUI.

To reduce flickering when resizing the window one could remove all gadgets from it on a IDCMP_SIZEVERIFY message.

Why don't you convert your programs from GadTools to ReAction? ReAction does all layouting automatically. That's much easier to program.

And Reaction looks better because it scaled to the font so you can see the text.

The problem with flickering is likely due to the larger numbers of IDCMP_NEWSIZE messages an app will get under OS4.x combined with the abilty to resie the window and contents continuosly.

To cope with this in a couple of apps I've had to update I set a flag when an IDCMP_NEWSIZE occurs then deal with it after the current batch of IDCMP messages has been processed.

eg (in psudo code)


I've used this approach to fix the non reaction main window of AWeb, dme and a few other small things "ported" from 3.x.


As Thomas says, it might be worth "upgrading" to a reactionGUI which will handle all the resizing etc for you