（LVGL）案例预览 键盘

static void ta_event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * ta = lv_event_get_target_obj(e);
    lv_obj_t * kb = (lv_obj_t *)lv_event_get_user_data(e);
    if(code == LV_EVENT_FOCUSED) {
        lv_keyboard_set_textarea(kb, ta);
        lv_obj_remove_flag(kb, LV_OBJ_FLAG_HIDDEN);
    }

    if(code == LV_EVENT_DEFOCUSED) {
        lv_keyboard_set_textarea(kb, NULL);
        lv_obj_add_flag(kb, LV_OBJ_FLAG_HIDDEN);
    }
}

void lv_example_keyboard_1(void)
{
    /*Create a keyboard to use it with an of the text areas*/
    lv_obj_t * kb = lv_keyboard_create(lv_screen_active());

    /*Create a text area. The keyboard will write here*/
    lv_obj_t * ta1;
    ta1 = lv_textarea_create(lv_screen_active());
    lv_obj_align(ta1, LV_ALIGN_TOP_LEFT, 10, 10);
    lv_obj_add_event_cb(ta1, ta_event_cb, LV_EVENT_ALL, kb);
    lv_textarea_set_placeholder_text(ta1, "Hello");
    lv_obj_set_size(ta1, 140, 80);

    lv_obj_t * ta2;
    ta2 = lv_textarea_create(lv_screen_active());
    lv_obj_align(ta2, LV_ALIGN_TOP_RIGHT, -10, 10);
    lv_obj_add_event_cb(ta2, ta_event_cb, LV_EVENT_ALL, kb);
    lv_obj_set_size(ta2, 140, 80);

    lv_keyboard_set_textarea(kb, ta1);

    /*The keyboard will show Arabic characters if they are enabled */
#if LV_USE_ARABIC_PERSIAN_CHARS && LV_FONT_DEJAVU_16_PERSIAN_HEBREW
    lv_obj_set_style_text_font(kb, &lv_font_dejavu_16_persian_hebrew, 0);
    lv_obj_set_style_text_font(ta1, &lv_font_dejavu_16_persian_hebrew, 0);
    lv_obj_set_style_text_font(ta2, &lv_font_dejavu_16_persian_hebrew, 0);
#endif
}

void lv_example_keyboard_2(void)
{
    /*Create an AZERTY keyboard map*/
    static const char * kb_map[] = {"A", "Z", "E", "R", "T", "Y", "U", "I", "O", "P", LV_SYMBOL_BACKSPACE, "\n",
                                    "Q", "S", "D", "F", "G", "J", "K", "L", "M",  LV_SYMBOL_NEW_LINE, "\n",
                                    "W", "X", "C", "V", "B", "N", ",", ".", ":", "!", "?", "\n",
                                    LV_SYMBOL_CLOSE, " ",  " ", " ", LV_SYMBOL_OK, NULL
                                   };

    /*Set the relative width of the buttons and other controls*/
    static const lv_buttonmatrix_ctrl_t kb_ctrl[] = {LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_6,
                                                     LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_6,
                                                     LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4, LV_BUTTONMATRIX_CTRL_WIDTH_4,
                                                     LV_BUTTONMATRIX_CTRL_WIDTH_2, (lv_buttonmatrix_ctrl_t)(LV_BUTTONMATRIX_CTRL_HIDDEN | LV_BUTTONMATRIX_CTRL_WIDTH_2), LV_BUTTONMATRIX_CTRL_WIDTH_6, (lv_buttonmatrix_ctrl_t)(LV_BUTTONMATRIX_CTRL_HIDDEN | LV_BUTTONMATRIX_CTRL_WIDTH_2), LV_BUTTONMATRIX_CTRL_WIDTH_2
                                                    };

    /*Create a keyboard and add the new map as USER_1 mode*/
    lv_obj_t * kb = lv_keyboard_create(lv_screen_active());

    lv_keyboard_set_map(kb, LV_KEYBOARD_MODE_USER_1, kb_map, kb_ctrl);
    lv_keyboard_set_mode(kb, LV_KEYBOARD_MODE_USER_1);

    /*Create a text area. The keyboard will write here*/
    lv_obj_t * ta;
    ta = lv_textarea_create(lv_screen_active());
    lv_obj_align(ta, LV_ALIGN_TOP_MID, 0, 10);
    lv_obj_set_size(ta, lv_pct(90), 80);
    lv_obj_add_state(ta, LV_STATE_FOCUSED);

    lv_keyboard_set_textarea(kb, ta);
}

static void event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target_obj(e);
    lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
    lv_draw_dsc_base_t * base_dsc = (lv_draw_dsc_base_t *)lv_draw_task_get_draw_dsc(draw_task);
    bool pressed = false;
    if(lv_keyboard_get_selected_button(obj) == base_dsc->id1 && lv_obj_has_state(obj, LV_STATE_PRESSED)) {
        pressed = true;
    }

    /*When the keyboard draws the buttons...*/
    if(base_dsc->part == LV_PART_ITEMS) {
        /*Get a color based on the button's index*/
        lv_palette_t palette = (lv_palette_t)(base_dsc->id1 % LV_PALETTE_LAST);
        lv_draw_fill_dsc_t * fill_draw_dsc = lv_draw_task_get_fill_dsc(draw_task);
        if(fill_draw_dsc) {
            fill_draw_dsc->color = pressed ? lv_palette_darken(palette, 3) : lv_palette_main(palette);
        }
        lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
        if(label_draw_dsc) {
            /*For the OK symbol, draw a star instead*/
            if(lv_strcmp(label_draw_dsc->text, LV_SYMBOL_OK) == 0) {
                label_draw_dsc->opa = 0;    /*Hide the label*/

                LV_IMAGE_DECLARE(img_star);
                lv_image_header_t header;
                lv_result_t res = lv_image_decoder_get_info(&img_star, &header);
                if(res != LV_RESULT_OK) return;

                lv_area_t a;
                lv_area_set(&a, 0, 0, header.w - 1, header.h - 1);
                lv_area_t draw_task_area;
                lv_draw_task_get_area(draw_task, &draw_task_area);
                lv_area_align(&draw_task_area, &a, LV_ALIGN_CENTER, 0, 0);

                lv_draw_image_dsc_t img_draw_dsc;
                lv_draw_image_dsc_init(&img_draw_dsc);
                img_draw_dsc.src = &img_star;
                lv_draw_image(base_dsc->layer, &img_draw_dsc, &a);
            }
            else {
                /*For the other labels just pick an lighter color*/
                label_draw_dsc->color = lv_palette_lighten(palette, 4);
            }
        }

    }
}

/**
 * Add custom drawer to the keyboard to customize the buttons one by one
 */
void lv_example_keyboard_3(void)
{
    lv_obj_t * kb = lv_keyboard_create(lv_screen_active());
    lv_obj_add_event_cb(kb, event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
    lv_obj_add_flag(kb, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
    lv_obj_center(kb);
}