I finally used for the example:
let btn_event_cb = block:
var cnt = 0
(proc (e:ptr lv_event_t) {.cdecl.} =
let code = lv_event_get_code(e)
let btn = cast[ptr lv_obj_t](lv_event_get_target(e))
if code == LV_EVENT_CLICKED:
echo now().utc, " clicked"
cnt += 1
# Get the first child of the button which is the label and change
its text*/
let label = lv_obj_get_child(btn, 0)
lv_label_set_text_fmt(label, "Button: %d", cnt) )
Run
which works. It seems to store `cnt` globally, but I don't know well how to
interpret the C generated code:
...
N_LIB_PRIVATE NI cnt__ex485195button_4 = ((NI) 0);
...
Run
I have to try to create that variable as user data. In [this
thread](https://forum.lvgl.io/t/user-data-context-for-event-callbacks/1177)
they suggest using `lv_obj_set_user_data`.
The issue was the loop at the bottom:
while true:
## Periodically call the lv_task handler.
## It could be done in a timer interrupt or an OS task too.
discard lv_timer_handler()
# sleep(5 * 1000) #<--- this was too big
sleep(5 * 10)
Run
I understand that the library was unable to catch the clicks due to this.
