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ndg/lib/lvgl/examples/others/msg/lv_example_msg_3.c

155 lines
4.7 KiB
C

#include "../../lv_examples.h"
#if LV_USE_MSG && LV_USE_SLIDER && LV_USE_LABEL && LV_BUILD_EXAMPLES
/*Define a message ID*/
#define MSG_INC 1
#define MSG_DEC 2
#define MSG_SET 3
#define MSG_UPDATE 4
#define MSG_UPDATE_REQUEST 5
static void value_handler(void * s, lv_msg_t * m);
static void value_handler(void * s, lv_msg_t * m);
static void btn_event_cb(lv_event_t * e);
static void label_event_cb(lv_event_t * e);
static void slider_event_cb(lv_event_t * e);
/**
* Show how an increment button, a decrement button, as slider can set a value
* and a label display it.
* The current value (i.e. the system's state) is stored only in one static variable in a function
* and no global variables are required.
*/
void lv_example_msg_3(void)
{
lv_msg_subsribe(MSG_INC, value_handler, NULL);
lv_msg_subsribe(MSG_DEC, value_handler, NULL);
lv_msg_subsribe(MSG_SET, value_handler, NULL);
lv_msg_subsribe(MSG_UPDATE, value_handler, NULL);
lv_msg_subsribe(MSG_UPDATE_REQUEST, value_handler, NULL);
lv_obj_t * panel = lv_obj_create(lv_scr_act());
lv_obj_set_size(panel, 250, LV_SIZE_CONTENT);
lv_obj_center(panel);
lv_obj_set_flex_flow(panel, LV_FLEX_FLOW_ROW);
lv_obj_set_flex_align(panel, LV_FLEX_ALIGN_SPACE_BETWEEN, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START);
lv_obj_t * btn;
lv_obj_t * label;
/*Up button*/
btn = lv_btn_create(panel);
lv_obj_set_flex_grow(btn, 1);
lv_obj_add_event_cb(btn, btn_event_cb, LV_EVENT_ALL, NULL);
label = lv_label_create(btn);
lv_label_set_text(label, LV_SYMBOL_LEFT);
lv_obj_center(label);
/*Current value*/
label = lv_label_create(panel);
lv_obj_set_flex_grow(label, 2);
lv_obj_set_style_text_align(label, LV_TEXT_ALIGN_CENTER, 0);
lv_label_set_text(label, "?");
lv_msg_subsribe_obj(MSG_UPDATE, label, NULL);
lv_obj_add_event_cb(label, label_event_cb, LV_EVENT_MSG_RECEIVED, NULL);
/*Down button*/
btn = lv_btn_create(panel);
lv_obj_set_flex_grow(btn, 1);
lv_obj_add_event_cb(btn, btn_event_cb, LV_EVENT_ALL, NULL);
label = lv_label_create(btn);
lv_label_set_text(label, LV_SYMBOL_RIGHT);
lv_obj_center(label);
/*Slider*/
lv_obj_t * slider = lv_slider_create(panel);
lv_obj_set_flex_grow(slider, 1);
lv_obj_add_flag(slider, LV_OBJ_FLAG_FLEX_IN_NEW_TRACK);
lv_obj_add_event_cb(slider, slider_event_cb, LV_EVENT_ALL, NULL);
lv_msg_subsribe_obj(MSG_UPDATE, slider, NULL);
/* As there are new UI elements that don't know the system's state
* send an UPDATE REQUEST message which will trigger an UPDATE message with the current value*/
lv_msg_send(MSG_UPDATE_REQUEST, NULL);
}
static void value_handler(void * s, lv_msg_t * m)
{
LV_UNUSED(s);
static int32_t value = 10;
int32_t old_value = value;
switch(lv_msg_get_id(m)) {
case MSG_INC:
if(value < 100) value++;
break;
case MSG_DEC:
if(value > 0) value--;
break;
case MSG_SET: {
const int32_t * new_value = lv_msg_get_payload(m);
value = *new_value;
}
break;
case MSG_UPDATE_REQUEST:
lv_msg_send(MSG_UPDATE, &value);
break;
default:
break;
}
if(value != old_value) {
lv_msg_send(MSG_UPDATE, &value);
}
}
static void btn_event_cb(lv_event_t * e)
{
lv_obj_t * btn = lv_event_get_target(e);
lv_event_code_t code = lv_event_get_code(e);
if(code == LV_EVENT_CLICKED || code == LV_EVENT_LONG_PRESSED_REPEAT) {
if(lv_obj_get_index(btn) == 0) { /*First object is the dec. button*/
lv_msg_send(MSG_DEC, NULL);
}
else {
lv_msg_send(MSG_INC, NULL);
}
}
}
static void label_event_cb(lv_event_t * e)
{
lv_obj_t * label = lv_event_get_target(e);
lv_event_code_t code = lv_event_get_code(e);
if(code == LV_EVENT_MSG_RECEIVED) {
lv_msg_t * m = lv_event_get_msg(e);
if(lv_msg_get_id(m) == MSG_UPDATE) {
const int32_t * v = lv_msg_get_payload(m);
lv_label_set_text_fmt(label, "%d %%", *v);
}
}
}
static void slider_event_cb(lv_event_t * e)
{
lv_obj_t * slider = lv_event_get_target(e);
lv_event_code_t code = lv_event_get_code(e);
if(code == LV_EVENT_VALUE_CHANGED) {
int32_t v = lv_slider_get_value(slider);
lv_msg_send(MSG_SET, &v);
}
else if(code == LV_EVENT_MSG_RECEIVED) {
lv_msg_t * m = lv_event_get_msg(e);
if(lv_msg_get_id(m) == MSG_UPDATE) {
const int32_t * v = lv_msg_get_payload(m);
lv_slider_set_value(slider, *v, LV_ANIM_OFF);
}
}
}
#endif