RT thread simulator lvgl control: switch switch button control

Preface

• switch button ： Switch button control , It also uses a lot , Here, I am familiar with the relevant operations

• switch There are two states ： On and off

Environment building

• RT-Thread 4.1.0 Or the latest version

• BSP Simulator simulator

• LVGL software package

function

• LVGL Draw a picture Switch Switch button , Draw a picture The label shows the status of the switch button

Operation method

• Here it is LVGL In the official routine , eureka switch Operation of space , A little familiar with Related large API, To write switch Button test code

• Storage location ：simulator\applications\lvgl\demo\lv_switch_01.c, The code is as follows

#include <rtthread.h>
#include <lvgl.h>

static lv_obj_t *lbl_status = NULL;

static void sw_event_cb(lv_event_t *e)
{
    
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t *sw = lv_event_get_target(e);

    if (lv_obj_has_state(sw, LV_STATE_CHECKED))
    {
    
        rt_kprintf("%s : power on \r\n", __func__);
        lv_label_set_text(lbl_status, "ON");
        lv_obj_align_to(lbl_status, sw, LV_ALIGN_OUT_RIGHT_MID, 20, 0);    /*Align top of the slider*/
    }
    else
    {
    
        lv_label_set_text(lbl_status, "OFF");
        lv_obj_align_to(lbl_status, sw, LV_ALIGN_OUT_RIGHT_MID, 20, 0);    /*Align top of the slider*/
        rt_kprintf("%s : power off \r\n", __func__);
    }
}

/** * Show an example to switch button */
void lv_switch_01_init(void)
{
    
    static rt_bool_t power_flag = RT_FALSE;

    lv_obj_t *sw = lv_switch_create(lv_scr_act());
    lv_obj_align(sw, LV_ALIGN_TOP_LEFT, 50, 20);
    lv_obj_add_event_cb(sw, sw_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    lv_obj_clear_state(sw, LV_STATE_CHECKED);

    /* Create a label */
    lbl_status = lv_label_create(lv_scr_act());
    lv_label_set_text(lbl_status, "OFF");
    lv_obj_align_to(lbl_status, sw, LV_ALIGN_OUT_RIGHT_MID, 20, 0);
}

• Call location ：simulator\packages\LVGL-latest\env_support\rt-thread\lv_rt_thread_port.c, It can also be placed in other places , Add the code file to visual studio 2022 In our project

Compile and run

• Add to RT-Thread Simulator Visual Studio 2022 In our project , Compile and run , The effect is as follows ：

switch Switch button API

• Set up switch Default on state ：lv_obj_add_state(sw, LV_STATE_CHECKED);

• Set up switch Off by default （ gray ） state ：lv_obj_clear_state(sw, LV_STATE_CHECKED);

• switch Whether it is on ：lv_obj_has_state(sw, LV_STATE_CHECKED)

• Set up switch State change callback function ：lv_obj_add_event_cb(sw, sw_event_cb, LV_EVENT_VALUE_CHANGED, NULL);

Summary

• Switch button Switch Widely used , Such as some power control, etc

• Use RT-Thread Simulator debugging LVGL, More efficient and convenient , And related code , It is easy to transplant to embedded hardware circuit board