LVGL V8之Extending the current theme

创建theme

• 定义style变量

static lv_style_t style_btn;

• theme回调处理

static void new_theme_apply_cb(lv_theme_t* th, lv_obj_t* obj)
{
    LV_UNUSED(th);
    if (lv_obj_check_type(obj, &lv_btn_class)) //检查是否为Button class
     {
        lv_obj_add_style(obj, &style_btn, 0); //添加style
    }
}

• 初时化style,设置背景颜色，边框颜色，边框宽度

    lv_style_init(&style_btn);
    lv_style_set_bg_color(&style_btn, lv_palette_main(LV_PALETTE_GREEN));
    lv_style_set_border_color(&style_btn, lv_palette_darken(LV_PALETTE_GREEN, 3));
    lv_style_set_border_width(&style_btn, 3);

• 获取显示主题

  lv_theme_t* th_act = lv_disp_get_theme(NULL);

• 保存显示主题到th_new变量

    static lv_theme_t th_new;
    th_new = *th_act;

• 设置parent对象的主题

  lv_theme_set_parent(&th_new, th_act);

• 设置主题回调处理函数

  lv_theme_set_apply_cb(&th_new, new_theme_apply_cb);

• 指定新的主题到当前显示

lv_disp_set_theme(NULL, &th_new);

• 创建旧主题Button

    lv_obj_t* btn;
    lv_obj_t* label;
    btn = lv_btn_create(lv_scr_act()); 
    lv_obj_align(btn, LV_ALIGN_TOP_MID, 0, 20);
    label = lv_label_create(btn);
    lv_label_set_text(label, "Original theme");

• 配置新主题后创建Button

    new_theme_init_and_set();
    btn = lv_btn_create(lv_scr_act());
    lv_obj_align(btn, LV_ALIGN_BOTTOM_MID, 0, -20);
    label = lv_label_create(btn);
    lv_label_set_text(label, "New theme");

完整代码，仅供参考

static lv_style_t style_btn;
static void new_theme_apply_cb(lv_theme_t* th, lv_obj_t* obj)
{
    LV_UNUSED(th);
    if (lv_obj_check_type(obj, &lv_btn_class)) {
        lv_obj_add_style(obj, &style_btn, 0);
    }
}

static void new_theme_init_and_set(void)
{
    /*Initialize the styles*/
    lv_style_init(&style_btn);
    lv_style_set_bg_color(&style_btn, lv_palette_main(LV_PALETTE_GREEN));
    lv_style_set_border_color(&style_btn, lv_palette_darken(LV_PALETTE_GREEN, 3));
    lv_style_set_border_width(&style_btn, 3);
    /*Initialize the new theme from the current theme*/
    lv_theme_t* th_act = lv_disp_get_theme(NULL);
    static lv_theme_t th_new;
    th_new = *th_act;
    /*Set the parent theme ans the style applay callback for the new theme*/
    lv_theme_set_parent(&th_new, th_act);
    lv_theme_set_apply_cb(&th_new, new_theme_apply_cb);
   

    /*Assign the new theme the the current display*/
    lv_disp_set_theme(NULL, &th_new);
}

static void lv_example_style_14(void)
{
    lv_obj_t* btn;
    lv_obj_t* label;
    btn = lv_btn_create(lv_scr_act());
    lv_obj_align(btn, LV_ALIGN_TOP_MID, 0, 20);
    label = lv_label_create(btn);
    lv_label_set_text(label, "Original theme");
    new_theme_init_and_set();
    btn = lv_btn_create(lv_scr_act());
    lv_obj_align(btn, LV_ALIGN_BOTTOM_MID, 0, -20);
    label = lv_label_create(btn);
    lv_label_set_text(label, "New theme");
}

调用lv_example_style_14运行效果