event_cb.user_data is limited to pointer, wishing to give it a little bit more usability

[JohnGoewert]

I was wanting to send an int defined as a const in globals.xml. Since event_cb in C code is a void*, it would be great to be able to convert over a defined into to a void*. This currently doesn't work as the global #define isn't a pointer.

XML:

       <element name="event_cb" access="add" type="void" help="Attach an event callback">
            <arg name="callback" type="event_cb" help="Callback function"/>
            <arg name="trigger" type="lv_event" default="clicked" help="Event to trigger callback"/>
            <arg name="user_data" type="string" default="NULL" help="Optional user data as a string"/>
        </element>

Use case:
In global.xml:

	<consts>
              <int name="HOME_SCREEN_ID" value="1" />
	</consts>

What I would like to be able to do in my screen.xml:

<event_cb callback="set_screen" trigger="clicked" user_data="#HOME_SCREEN_ID" />

The reason for this is so that I can do a big switch case instead of a few hundred strcmp()'s to handle things like my screen transitions or passing one of 400 different error codes.

[richardgazdik]

Thank you for the suggestion. We will review it with our team and inform you once we have decided on how to proceed with this idea.

[kisvegabor]

@richardgazdik @mrhubbs
In C we can do this:

<project_name>_gen.h

#ifndef  LV_TO_STR
#define __LV_TO_STR_HELPER(x) #x
#define LV_TO_STR(x) __LV_TO_STR_HELPER(x)
#endif

Assuming that there is a constant like

#define NUMBER 12

In the event's code export we can do this if the constant's type is int:

lv_obj_add_event(other_parameters , LV_TO_STR(NUMBER));

What do you think?

[github-actions]

This issue has been inactive for 30 days.

[JohnGoewert]

That would be useful. I'm doing some similar functions to reduce Strings being passed around in C instead of just sending id numbers.

[github-actions]

This issue has been inactive for 30 days.

[laszlobalint]

@kisvegabor, @richardgazdik, @mrhubbs, should we go ahead with Gabor's suggestion?