Enable touchscreen in LVGL project on Raspberry Pi

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1

Hello,

I’m running lv_port_linux_frame_buffer project on my Raspberry Pi with touchscreen connected. Touchscreen works fine in X windows in general, but not work in sample in project that runs in console.

I was using button sample unit for my test and was expecting to get something to event_handler, but got nothing. What might be wrong?

#include "../../../lv_examples.h"
#include <stdio.h>
#if LV_USE_BTN

static void event_handler(lv_obj_t * obj, lv_event_t event)
{
    if(event == LV_EVENT_CLICKED) {
        printf("Clicked\n");
    }
    else if(event == LV_EVENT_VALUE_CHANGED) {
        printf("Toggled\n");
    }
}

void lv_ex_btn_1(void)
{
    lv_obj_t * label;

    lv_obj_t * btn1 = lv_btn_create(lv_scr_act(), NULL);
    lv_obj_set_event_cb(btn1, event_handler);
    lv_obj_align(btn1, NULL, LV_ALIGN_CENTER, 0, -40);

    label = lv_label_create(btn1, NULL);
    lv_label_set_text(label, "Button");

    lv_obj_t * btn2 = lv_btn_create(lv_scr_act(), NULL);
    lv_obj_set_event_cb(btn2, event_handler);
    lv_obj_align(btn2, NULL, LV_ALIGN_CENTER, 0, 40);
    lv_btn_set_checkable(btn2, true);
    lv_btn_toggle(btn2);
    lv_btn_set_fit2(btn2, LV_FIT_NONE, LV_FIT_TIGHT);

    label = lv_label_create(btn2, NULL);
    lv_label_set_text(label, "Toggled");
}
2

You need to register and initialize the evdev driver for touch to work. You will also need to check that the right event device is selected in lv_drv_conf.h. The evtest /dev/input/eventX command might be useful.

    evdev_init();
    lv_indev_drv_t indev_drv;
    lv_indev_drv_init(&indev_drv);
    indev_drv.type = LV_INDEV_TYPE_POINTER;
    indev_drv.read_cb = evdev_read;
    lv_indev_drv_register(&indev_drv);