LVGL学习笔记 显示和隐藏 对象的属性标志位 配置

在显示GUI的过程中需要对某些对象进行临时隐藏或临时显示,因此需要对该对象的FLAG进行配置就可以实现对象的显示和隐藏了.

调用如下接口可以实现:

 lv_obj_add_flag(user_obj, LV_OBJ_FLAG_HIDDEN);//隐藏对象
 lv_obj_clear_flag(user_obj, LV_OBJ_FLAG_HIDDEN);//取消隐藏

实现的函数如下:

/*-----------------
 * Attribute set
 *----------------*/

void lv_obj_add_flag(lv_obj_t * obj, lv_obj_flag_t f)
{
    LV_ASSERT_OBJ(obj, MY_CLASS);

    bool was_on_layout = lv_obj_is_layout_positioned(obj);

    if(f & LV_OBJ_FLAG_HIDDEN) lv_obj_invalidate(obj);

    obj->flags |= f;

    if(f & LV_OBJ_FLAG_HIDDEN) {
        lv_obj_invalidate(obj);
    }

    if((was_on_layout != lv_obj_is_layout_positioned(obj)) || (f & (LV_OBJ_FLAG_LAYOUT_1 |  LV_OBJ_FLAG_LAYOUT_2))) {
        lv_obj_mark_layout_as_dirty(lv_obj_get_parent(obj));
        lv_obj_mark_layout_as_dirty(obj);
    }

    if(f & LV_OBJ_FLAG_SCROLLABLE) {
        lv_area_t hor_area, ver_area;
        lv_obj_get_scrollbar_area(obj, &hor_area, &ver_area);
        lv_obj_invalidate_area(obj, &hor_area);
        lv_obj_invalidate_area(obj, &ver_area);
    }
}

void lv_obj_clear_flag(lv_obj_t * obj, lv_obj_flag_t f)
{
    LV_ASSERT_OBJ(obj, MY_CLASS);

    bool was_on_layout = lv_obj_is_layout_positioned(obj);
    if(f & LV_OBJ_FLAG_SCROLLABLE) {
        lv_area_t hor_area, ver_area;
        lv_obj_get_scrollbar_area(obj, &hor_area, &ver_area);
        lv_obj_invalidate_area(obj, &hor_area);
        lv_obj_invalidate_area(obj, &ver_area);
    }

    obj->flags &= (~f);

    if(f & LV_OBJ_FLAG_HIDDEN) {
        lv_obj_invalidate(obj);
        if(lv_obj_is_layout_positioned(obj)) {
            lv_obj_mark_layout_as_dirty(lv_obj_get_parent(obj));
            lv_obj_mark_layout_as_dirty(obj);
        }
    }

    if((was_on_layout != lv_obj_is_layout_positioned(obj)) || (f & (LV_OBJ_FLAG_LAYOUT_1 |  LV_OBJ_FLAG_LAYOUT_2))) {
        lv_obj_mark_layout_as_dirty(lv_obj_get_parent(obj));
    }

}

其中还有很多其他配置如下:

/**
 * On/Off features controlling the object's behavior.
 * OR-ed values are possible
 */
enum {
    LV_OBJ_FLAG_HIDDEN          = (1L << 0),  /**< Make the object hidden. (Like it wasn't there at all)*/
    LV_OBJ_FLAG_CLICKABLE       = (1L << 1),  /**< Make the object clickable by the input devices*/
    LV_OBJ_FLAG_CLICK_FOCUSABLE = (1L << 2),  /**< Add focused state to the object when clicked*/
    LV_OBJ_FLAG_CHECKABLE       = (1L << 3),  /**< Toggle checked state when the object is clicked*/
    LV_OBJ_FLAG_SCROLLABLE      = (1L << 4),  /**< Make the object scrollable*/
    LV_OBJ_FLAG_SCROLL_ELASTIC  = (1L << 5),  /**< Allow scrolling inside but with slower speed*/
    LV_OBJ_FLAG_SCROLL_MOMENTUM = (1L << 6),  /**< Make the object scroll further when "thrown"*/
    LV_OBJ_FLAG_SCROLL_ONE      = (1L << 7),  /**< Allow scrolling only one snappable children*/
    LV_OBJ_FLAG_SCROLL_CHAIN_HOR = (1L << 8), /**< Allow propagating the horizontal scroll to a parent*/
    LV_OBJ_FLAG_SCROLL_CHAIN_VER = (1L << 9), /**< Allow propagating the vertical scroll to a parent*/
    LV_OBJ_FLAG_SCROLL_CHAIN     = (LV_OBJ_FLAG_SCROLL_CHAIN_HOR | LV_OBJ_FLAG_SCROLL_CHAIN_VER),
    LV_OBJ_FLAG_SCROLL_ON_FOCUS = (1L << 10),  /**< Automatically scroll object to make it visible when focused*/
    LV_OBJ_FLAG_SCROLL_WITH_ARROW  = (1L << 11), /**< Allow scrolling the focused object with arrow keys*/
    LV_OBJ_FLAG_SNAPPABLE       = (1L << 12), /**< If scroll snap is enabled on the parent it can snap to this object*/
    LV_OBJ_FLAG_PRESS_LOCK      = (1L << 13), /**< Keep the object pressed even if the press slid from the object*/
    LV_OBJ_FLAG_EVENT_BUBBLE    = (1L << 14), /**< Propagate the events to the parent too*/
    LV_OBJ_FLAG_GESTURE_BUBBLE  = (1L << 15), /**< Propagate the gestures to the parent*/
    LV_OBJ_FLAG_ADV_HITTEST     = (1L << 16), /**< Allow performing more accurate hit (click) test. E.g. consider rounded corners.*/
    LV_OBJ_FLAG_IGNORE_LAYOUT   = (1L << 17), /**< Make the object position-able by the layouts*/
    LV_OBJ_FLAG_FLOATING        = (1L << 18), /**< Do not scroll the object when the parent scrolls and ignore layout*/
    LV_OBJ_FLAG_OVERFLOW_VISIBLE = (1L << 19), /**< Do not clip the children's content to the parent's boundary*/

    LV_OBJ_FLAG_LAYOUT_1        = (1L << 23), /**< Custom flag, free to use by layouts*/
    LV_OBJ_FLAG_LAYOUT_2        = (1L << 24), /**< Custom flag, free to use by layouts*/

    LV_OBJ_FLAG_WIDGET_1        = (1L << 25), /**< Custom flag, free to use by widget*/
    LV_OBJ_FLAG_WIDGET_2        = (1L << 26), /**< Custom flag, free to use by widget*/
    LV_OBJ_FLAG_USER_1          = (1L << 27), /**< Custom flag, free to use by user*/
    LV_OBJ_FLAG_USER_2          = (1L << 28), /**< Custom flag, free to use by user*/
    LV_OBJ_FLAG_USER_3          = (1L << 29), /**< Custom flag, free to use by user*/
    LV_OBJ_FLAG_USER_4          = (1L << 30), /**< Custom flag, free to use by user*/

};