Base object（基础对象） (lv_obj)

Overview

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The 'Base Object' implements the basic properties of widgets on a screen, such as:

• coordinates

• parent object

• children

• contains the styles

• attributes like Clickable, Scrollable, etc.

In object-oriented thinking, it is the base class from which all other objects in LVGL are inherited.

The functions and functionalities of the Base object can be used with other widgets too. For example lv_obj_set_width(slider, 100)

The Base object can be directly used as a simple widget: it's nothing more than a rectangle. In HTML terms, think of it as a <div>.

基础对象 实现了屏幕上组件的基本属性，例如：

• 坐标

• 父对象

• 基于父对象的后代

• 包含样式

• 诸如 Clickable、Scrollable 等属性。

在面向对象的思想中，基础对象 是 LVGL 中所有其他对象都继承自的基类。

基础对象的功能可以与其他组件一起使用。 例如 lv_obj_set_width(slider, 100);

基础对象可以直接用作一个简单的组件：它只不过是一个矩形。 在 HTML 术语中，将其视为 <\div>。

Coordinates（坐标）

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Only a small subset of coordinate settings is described here. To see all the features of LVGL (padding, coordinates in styles, layouts, etc) visit the Coordinates page.

此处仅描述了一小部分坐标设置。要查看 LVGL 的所有功能（填充、样式中的坐标、布局等），请阅读 坐标 页面了解。

Size（大小）

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The object size can be modified on individual axes with lv_obj_set_width(obj, new_width); and lv_obj_set_height(obj, new_height);, or both axes can be modified at the same time with lv_obj_set_size(obj, new_width, new_height);.

可以使用lv_obj_set_width(obj, new_width); 和lv_obj_set_height(obj, new_height); 设置或修改单个轴上的对象大小，或者可以同时修改两个轴，使用 lv_obj_set_width(obj,new_set_width); 设置或修改高度 。

Position（位置）

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You can set the position relative to the parent with lv_obj_set_x(obj, new_x); and lv_obj_set_y(obj, new_y);, or both axes at the same time with lv_obj_set_pos(obj, new_x, new_y);.

您可以使用 lv_obj_set_x(obj, new_x); 和 lv_obj_set_y(obj, new_y); 设置相对于父级的位置，或者使用lv_obj_set_pos(obj, new_x, new_y); 来同时设置两个轴的位置。

Alignment（对齐）

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You can align the object on its parent with lv_obj_set_align(obj, LV_ALIGN_...);. After this every x and y setting will be relative to the set alignment mode. For example, this will shift the object by 10;20 px from the center of its parent:

您可以使用 lv_obj_set_align(obj, LV_ALIGN_...) 将对象参照其父对象对齐。此后，每个 x 和 y 设置都将适用于设置对齐模式。例如，这会将对象从其父对象的中心移动 10(x)，20(y) 像素：

lv_obj_set_align(obj, LV_ALIGN_CENTER);
lv_obj_set_pos(obj, 10, 20);

//Or in one function
lv_obj_align(obj, LV_ALIGN_CENTER, 10, 20);

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To align one object to another use lv_obj_align_to(obj_to_align, obj_referece, LV_ALIGN_..., x, y);

For example, to align a text below an image: lv_obj_align_to(text, image, LV_ALIGN_OUT_BOTTOM_MID, 0, 10);.

The following align types exist:

要将一个对象参照另一个对象对齐，请使用lv_obj_align_to(obj_to_align, obj_referece, LV_ALIGN_..., x, y);

例如，让图片下方的文本参照图片对齐：lv_obj_align_to(text, image, LV_ALIGN_OUT_BOTTOM_MID, 0, 10);。

存在以下对齐类型：

Parents and children（父母和孩子）

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You can set a new parent for an object with lv_obj_set_parent(obj, new_parent);. To get the current parent, use lv_obj_get_parent(obj);.

To get a specific children of a parent use lv_obj_get_child(parent, idx);. Some examples for idx:

• 0 get the child created first child

• 1 get the child created second

• -1 get the child created last

The children can be iterated lke this

您可以使用 lv_obj_set_parent(obj, new_parent); 为对象设置新的父级。要获取当前父级，请使用 lv_obj_get_parent(obj);。

要获取父母的特定孩子，请使用lv_obj_get_child(parent, idx);。 idx 的一些示例：

• 0 获取创建的第一个子项

• 1 获取创建的第二个子项

• -1 获取最后创建的子项

父级的孩子们可以这样迭代

uint32_t i;
for(i = 0; i < lv_obj_get_child_cnt(parent); i++) {
  lv_obj_t * child = lv_obj_get_child(paernt, i);
  /*Do something with child*/
}

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lv_obj_get_index(obj) returns the index of the object in its parent. It is equivalent to the number of younger children in the parent.

You can bring an object to the foreground or send it to the background with lv_obj_move_foreground(obj) and lv_obj_move_background(obj).

You can change the index of an object in its parent using lv_obj_move_to_index(obj, index).

You can swap the position of two objects with lv_obj_swap(obj1, obj2).

lv_obj_get_index(obj); 返回对象在其父对象中的索引。 它相当于父对象拥有的孩子数量。

您可以使用lv_obj_move_foreground(obj); 和lv_obj_move_background(obj); 将对象带到前台或将其发移到后台。

您可以使用 lv_obj_move_to_index(obj, index); 更改对象在其父对象中的索引。

你可以用 lv_obj_swap(obj1, obj2); 交换两个对象的位置(列表框中，它可用于对列表框项目进行排序。)。

Display and Screens(显示和屏幕)

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At the highest level of the LVGL object hierarchy is the display which represents the driver for a display device (physical display or simulator). A display can have one or more screens associated with it. Each screen contains a hierarchy of objects for graphical widgets representing a layout that covers the entire display.

When you have created a screen like lv_obj_t * screen = lv_obj_create(NULL), you can make it active with lv_scr_load(screen). The lv_scr_act() function gives you a pointer to the active screen.

If you have multiple displays, it's important to know that the screen functions operate on the most recently created display or the one explicitly selected with lv_disp_set_default.

To get an object's screen use the lv_obj_get_screen(obj) function.

在 LVGL 中，对象层次结构的最高级别是 display，它代表显示设备（物理显示器或模拟器）的驱动程序。 一个显示器可以有一个或多个与其相关联的屏幕。 每个屏幕都包含图形组件的对象层次结构，代表覆盖整个显示的布局。

当你创建了一个像 lv_obj_t * screen = lv_obj_create(NULL); 这样的屏幕时，你可以用 lv_scr_load(screen); 激活它。 lv_scr_act() 函数为您提供指向活动屏幕的指针。

如果您有多个显示器，重要的是要知道，最后创建的显示器时指定了屏幕，或者是用 lv_disp_set_default 明确切换的。

要获取对象的屏幕，请使用 lv_obj_get_screen(obj); 函数。

Events（事件）

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To set an event callback for an object, use lv_obj_add_event_cb(obj, event_cb, LV_EVENT_..., user_data),

To manually send an event to an object, use lv_event_send(obj, LV_EVENT_..., param)

Read the Event overview to learn more about events.

要为对象设置事件回调，请使用 lv_obj_add_event_cb(obj, event_cb, LV_EVENT_..., user_data); ，

要手动向对象发送事件，请使用 lv_event_send(obj, LV_EVENT_..., param);

阅读 事件概述 页面，以了解有关事件的更多信息。

Styles（样式）

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Be sure to read the Style overview. Here only the most essential functions are described.

A new style can be added to an object with the lv_obj_add_style(obj, &new_style, selector) function. selector is an ORed combination of part and state(s). E.g. LV_PART_SCROLLBAR | LV_STATE_PRESSED.

The base objects use LV_PART_MAIN style properties and LV_PART_SCROLLBAR with the typical backgroud style properties.

这里只介绍最基本的功能，请务必阅读样式概述页面详细了解。

可以使用 lv_obj_add_style(obj, &new_style, selector) 函数向对象添加新样式。

selector 可以组合使用。 例如。 LV_PART_SCROLLBAR | LV_STATE_PRESSED。

基本对象使用 LV_PART_MAIN 样式属性和带有典型背景样式属性的 LV_PART_SCROLLBAR 。

Flags（宏开关）

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There are some attributes which can be enabled/disabled by lv_obj_add/clear_flag(obj, LV_OBJ_FLAG_...):

• LV_OBJ_FLAG_HIDDEN Make the object hidden. (Like it wasn't there at all)

• LV_OBJ_FLAG_CLICKABLE Make the object clickable by input devices

• LV_OBJ_FLAG_CLICK_FOCUSABLE Add focused state to the object when clicked

• LV_OBJ_FLAG_CHECKABLE Toggle checked state when the object is clicked

• LV_OBJ_FLAG_SCROLLABLE Make the object scrollable

• LV_OBJ_FLAG_SCROLL_ELASTIC Allow scrolling inside but with slower speed

• LV_OBJ_FLAG_SCROLL_MOMENTUM Make the object scroll further when "thrown"

• LV_OBJ_FLAG_SCROLL_ONE Allow scrolling only one snappable children

• LV_OBJ_FLAG_SCROLL_CHAIN Allow propagating the scroll to a parent

• LV_OBJ_FLAG_SCROLL_ON_FOCUS Automatically scroll object to make it visible when focused

• LV_OBJ_FLAG_SNAPPABLE If scroll snap is enabled on the parent it can snap to this object

• LV_OBJ_FLAG_PRESS_LOCK Keep the object pressed even if the press slid from the object

• LV_OBJ_FLAG_EVENT_BUBBLE Propagate the events to the parent too

• LV_OBJ_FLAG_GESTURE_BUBBLE Propagate the gestures to the parent

• LV_OBJ_FLAG_ADV_HITTEST Allow performing more accurate hit (click) test. E.g. accounting for rounded corners

• LV_OBJ_FLAG_IGNORE_LAYOUT Make the object positionable by the layouts

• LV_OBJ_FLAG_FLOATING Do not scroll the object when the parent scrolls and ignore layout

• LV_OBJ_FLAG_LAYOUT_1 Custom flag, free to use by layouts

• LV_OBJ_FLAG_LAYOUT_2 Custom flag, free to use by layouts

• LV_OBJ_FLAG_WIDGET_1 Custom flag, free to use by widget

• LV_OBJ_FLAG_WIDGET_2 Custom flag, free to use by widget

• LV_OBJ_FLAG_USER_1 Custom flag, free to use by user

• LV_OBJ_FLAG_USER_2 Custom flag, free to use by user

• LV_OBJ_FLAG_USER_3 Custom flag, free to use by user

• LV_OBJ_FLAG_USER_4 Custom flag, free to use by user

Some examples:

有一些属性可以通过lv_obj_add/clear_flag(obj, LV_OBJ_FLAG_...);启用/禁用：

• LV_OBJ_FLAG_HIDDEN 隐藏对象。 （就像它根本不存在一样）

• LV_OBJ_FLAG_CLICKABLE 使输入设备可点击对象

• LV_OBJ_FLAG_CLICK_FOCUSABLE 单击时将焦点状态添加到对象

• LV_OBJ_FLAG_CHECKABLE 对象被点击时切换选中状态

• LV_OBJ_FLAG_SCROLLABLE 使对象可滚动

• LV_OBJ_FLAG_SCROLL_ELASTIC 允许在内部滚动但速度较慢

• LV_OBJ_FLAG_SCROLL_MOMENTUM 在“抛出”时使对象滚动得更远

• LV_OBJ_FLAG_SCROLL_ONE 只允许滚动一个可捕捉的孩子

• LV_OBJ_FLAG_SCROLL_CHAIN 允许将滚动传播到父级

• LV_OBJ_FLAG_SCROLL_ON_FOCUS 自动滚动对象以使其在聚焦时可见

• LV_OBJ_FLAG_SNAPPABLE 如果在父对象上启用了滚动捕捉，它可以捕捉到这个对象

• LV_OBJ_FLAG_PRESS_LOCK 保持对象被按下，即使按下从对象上滑动

• LV_OBJ_FLAG_EVENT_BUBBLE 也将事件传播给父级

• LV_OBJ_FLAG_GESTURE_BUBBLE 将手势传播给父级

• LV_OBJ_FLAG_ADV_HITTEST 允许执行更准确的命中（点击）测试。例如。考虑圆角。

• LV_OBJ_FLAG_IGNORE_LAYOUT 使对象可以通过布局定位

• LV_OBJ_FLAG_FLOATING 父滚动时不滚动对象，忽略布局

• LV_OBJ_FLAG_LAYOUT_1 自定义标志，可供布局免费使用

• LV_OBJ_FLAG_LAYOUT_2 自定义标志，可供布局免费使用

• LV_OBJ_FLAG_WIDGET_1 自定义标志，组件免费使用

• LV_OBJ_FLAG_WIDGET_2 自定义标志，组件免费使用

• LV_OBJ_FLAG_USER_1 自定义标志，用户免费使用

• LV_OBJ_FLAG_USER_2 自定义标志，用户免费使用

• LV_OBJ_FLAG_USER_3 自定义标志，用户免费使用

• LV_OBJ_FLAG_USER_4 自定义标志，由用户部分免费使用。

示例：

/*Hide on object*/
lv_obj_add_flag(obj, LV_OBJ_FLAG_HIDDEN);

/*Make an obejct non-clickable*/
lv_obj_clear_flag(obj, LV_OBJ_FLAG_CLICKABLE);

Groups

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Read the Input devices overview to learn more about Groups.

Objects are added to a group with lv_group_add_obj(group, obj), and you can use lv_obj_get_group(obj) to see which group an object belongs to.

lv_obj_is_focused(obj) returns if the object is currently focused on its group or not. If the object is not added to a group, false will be returned.

阅读 输入设备概述 以了解有关 Groups 的更多信息。

使用lv_group_add_obj(group, obj);将对象添加到组，您可以使用lv_obj_get_group(obj);查看对象属于哪个组。

lv_obj_is_focused(obj); 返回对象当前是否聚焦在其组上。 如果对象未添加到组中，则将返回 false。

Extended click area（拓展的点击区域）

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By default, the objects can be clicked only on their coordinates, however, this area can be extended with lv_obj_set_ext_click_area(obj, size).

默认情况下，只能在对象的坐标上单击对象，但是，可以使用 lv_obj_set_ext_click_area(obj, size); 扩展该区域。

Events（事件）

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• LV_EVENT_VALUE_CHANGED when the LV_OBJ_FLAG_CHECKABLE flag is enabled and the object clicked (on transition to/from the checked state)

• LV_EVENT_DRAW_PART_BEGIN and LV_EVENT_DRAW_PART_END is sent for the following types:

  • LV_OBJ_DRAW_PART_RECTANGLE The main rectangle

    • part: LV_PART_MAIN

    • rect_dsc

    • draw_area: the area of the rectangle

  • LV_OBJ_DRAW_PART_BORDER_POST The border if the border_post style property is true

    • part: LV_PART_MAIN

    • rect_dsc

    • draw_area: the area of the rectangle

  • LV_OBJ_DRAW_PART_SCROLLBAR the scrollbars

    • part: LV_PART_SCROLLBAR

    • rect_dsc

    • draw_area: the area of the rectangle

Learn more about Events.

• LV_EVENT_VALUE_CHANGED 当LV_OBJ_FLAG_CHECKABLE 标志被启用并且对象被点击时（转换到/从选中状态）

• 为以下类型发送LV_EVENT_DRAW_PART_BEGIN和LV_EVENT_DRAW_PART_END：

  • LV_OBJ_DRAW_PART_RECTANGLE 主矩形

    • 部分：LV_PART_MAIN -rect_dsc

    • draw_area：矩形的面积

  • LV_OBJ_DRAW_PART_BORDER_POST 如果border_post 样式属性为true 的边框

    • 部分：LV_PART_MAIN -rect_dsc

    • draw_area：矩形的面积

  • LV_OBJ_DRAW_PART_SCROLLBAR 滚动条

    • 部分：LV_PART_SCROLLBAR -rect_dsc

    • draw_area：矩形的面积

详细了解事件。

Keys

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If LV_OBJ_FLAG_CHECKABLE is enabled, LV_KEY_RIGHT and LV_KEY_UP make the object checked, and LV_KEY_LEFT and LV_KEY_DOWN make it unchecked.

If LV_OBJ_FLAG_SCROLLABLE is enabled, but the object is not editable (as declared by the widget class), the arrow keys (LV_KEY_UP, LV_KEY_DOWN, LV_KEY_LEFT, LV_KEY_RIGHT) scroll the object. If the object can only scroll vertically, LV_KEY_LEFT and LV_KEY_RIGHT will scroll up/down instead, making it compatible with an encoder input device. See Input devices overview for more on encoder behaviors and the edit mode.

如果启用了LV_OBJ_FLAG_CHECKABLE，则LV_KEY_RIGHT 和LV_KEY_UP 使对象被选中，而LV_KEY_LEFT 和LV_KEY_DOWN 使其取消选中。

如果启用了“LV_OBJ_FLAG_SCROLLABLE”，但对象不可编辑（由组件类声明），则箭头键（“LV_KEY_UP”、“LV_KEY_DOWN”、“LV_KEY_LEFT”、“LV_KEY_RIGHT”）滚动对象。 如果对象只能垂直滚动，LV_KEY_LEFT 和 LV_KEY_RIGHT 将改为向上/向下滚动，使其与编码器输入设备兼容。 有关编码器行为和编辑模式的更多信息，请参阅 输入设备概述。

了解有关 Keys 的更多信息。

Example

Base objects with custom styles

C code  

 GitHub

#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES

void lv_example_obj_1(void)
{
    lv_obj_t * obj1;
    obj1 = lv_obj_create(lv_scr_act());
    lv_obj_set_size(obj1, 100, 50);
    lv_obj_align(obj1, LV_ALIGN_CENTER, -60, -30);

    static lv_style_t style_shadow;
    lv_style_init(&style_shadow);
    lv_style_set_shadow_width(&style_shadow, 10);
    lv_style_set_shadow_spread(&style_shadow, 5);
    lv_style_set_shadow_color(&style_shadow, lv_palette_main(LV_PALETTE_BLUE));

    lv_obj_t * obj2;
    obj2 = lv_obj_create(lv_scr_act());
    lv_obj_add_style(obj2, &style_shadow, 0);
    lv_obj_align(obj2, LV_ALIGN_CENTER, 60, 30);
}
#endif

MicroPython code  

 GitHub Simulator

obj1 = lv.obj(lv.scr_act())
obj1.set_size(100, 50)
obj1.align(lv.ALIGN.CENTER, -60, -30)

style_shadow = lv.style_t()
style_shadow.init()
style_shadow.set_shadow_width(10)
style_shadow.set_shadow_spread(5)
style_shadow.set_shadow_color(lv.palette_main(lv.PALETTE.BLUE))

obj2 = lv.obj(lv.scr_act())
obj2.add_style(style_shadow, 0)
obj2.align(lv.ALIGN.CENTER, 60, 30)

---

Make an object draggable

C code  

 GitHub

#include "../../lv_examples.h"
#if LV_BUILD_EXAMPLES

static void drag_event_handler(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target(e);

    lv_indev_t * indev = lv_indev_get_act();
    if(indev == NULL)  return;

    lv_point_t vect;
    lv_indev_get_vect(indev, &vect);

    lv_coord_t x = lv_obj_get_x(obj) + vect.x;
    lv_coord_t y = lv_obj_get_y(obj) + vect.y;
    lv_obj_set_pos(obj, x, y);
}


/**
 * Make an object dragable.
 */
void lv_example_obj_2(void)
{
    lv_obj_t * obj;
    obj = lv_obj_create(lv_scr_act());
    lv_obj_set_size(obj, 150, 100);
    lv_obj_add_event_cb(obj, drag_event_handler, LV_EVENT_PRESSING, NULL);

    lv_obj_t * label = lv_label_create(obj);
    lv_label_set_text(label, "Drag me");
    lv_obj_center(label);

}
#endif

MicroPython code  

 GitHub Simulator

def drag_event_handler(e):

    obj = e.get_target()

    indev = lv.indev_get_act()

    vect = lv.point_t()
    indev.get_vect(vect)
    x = obj.get_x() + vect.x
    y = obj.get_y() + vect.y
    obj.set_pos(x, y)


#
# Make an object dragable.
#

obj = lv.obj(lv.scr_act())
obj.set_size(150, 100)
obj.add_event_cb(drag_event_handler, lv.EVENT.PRESSING, None)

label = lv.label(obj)
label.set_text("Drag me")
label.center()

---

API

Typedefs

typedef uint16_t lv_state_t

typedef uint32_t lv_part_t

typedef uint32_t lv_obj_flag_t

typedef struct _lv_obj_t lv_obj_t

Enums

enum [anonymous]

Possible states of a widget. OR-ed values are possible

Values:

enumerator LV_STATE_DEFAULT

enumerator LV_STATE_CHECKED

enumerator LV_STATE_FOCUSED

enumerator LV_STATE_FOCUS_KEY

enumerator LV_STATE_EDITED

enumerator LV_STATE_HOVERED

enumerator LV_STATE_PRESSED

enumerator LV_STATE_SCROLLED

enumerator LV_STATE_DISABLED

enumerator LV_STATE_USER_1

enumerator LV_STATE_USER_2

enumerator LV_STATE_USER_3

enumerator LV_STATE_USER_4

enumerator LV_STATE_ANY

Special value can be used in some functions to target all states

enum [anonymous]

The possible parts of widgets. The parts can be considered as the internal building block of the widgets. E.g. slider = background + indicator + knob Note every part is used by every widget

Values:

enumerator LV_PART_MAIN

A background like rectangle

enumerator LV_PART_SCROLLBAR

The scrollbar(s)

enumerator LV_PART_INDICATOR

Indicator, e.g. for slider, bar, switch, or the tick box of the checkbox

enumerator LV_PART_KNOB

Like handle to grab to adjust the value

enumerator LV_PART_SELECTED

Indicate the currently selected option or section

enumerator LV_PART_ITEMS

Used if the widget has multiple similar elements (e.g. table cells)

enumerator LV_PART_TICKS

Ticks on scale e.g. for a chart or meter

enumerator LV_PART_CURSOR

Mark a specific place e.g. for text area's cursor or on a chart

enumerator LV_PART_CUSTOM_FIRST

Extension point for custom widgets

enumerator LV_PART_ANY

Special value can be used in some functions to target all parts

enum [anonymous]

On/Off features controlling the object's behavior. OR-ed values are possible

Values:

enumerator LV_OBJ_FLAG_HIDDEN

Make the object hidden. (Like it wasn't there at all)

enumerator LV_OBJ_FLAG_CLICKABLE

Make the object clickable by the input devices

enumerator LV_OBJ_FLAG_CLICK_FOCUSABLE

Add focused state to the object when clicked

enumerator LV_OBJ_FLAG_CHECKABLE

Toggle checked state when the object is clicked

enumerator LV_OBJ_FLAG_SCROLLABLE

Make the object scrollable

enumerator LV_OBJ_FLAG_SCROLL_ELASTIC

Allow scrolling inside but with slower speed

enumerator LV_OBJ_FLAG_SCROLL_MOMENTUM

Make the object scroll further when "thrown"

enumerator LV_OBJ_FLAG_SCROLL_ONE

Allow scrolling only one snappable children

enumerator LV_OBJ_FLAG_SCROLL_CHAIN_HOR

Allow propagating the horizontal scroll to a parent

enumerator LV_OBJ_FLAG_SCROLL_CHAIN_VER

Allow propagating the vertical scroll to a parent

enumerator LV_OBJ_FLAG_SCROLL_CHAIN

enumerator LV_OBJ_FLAG_SCROLL_ON_FOCUS

Automatically scroll object to make it visible when focused

enumerator LV_OBJ_FLAG_SCROLL_WITH_ARROW

Allow scrolling the focused object with arrow keys

enumerator LV_OBJ_FLAG_SNAPPABLE

If scroll snap is enabled on the parent it can snap to this object

enumerator LV_OBJ_FLAG_PRESS_LOCK

Keep the object pressed even if the press slid from the object

enumerator LV_OBJ_FLAG_EVENT_BUBBLE

Propagate the events to the parent too

enumerator LV_OBJ_FLAG_GESTURE_BUBBLE

Propagate the gestures to the parent

enumerator LV_OBJ_FLAG_ADV_HITTEST

Allow performing more accurate hit (click) test. E.g. consider rounded corners.

enumerator LV_OBJ_FLAG_IGNORE_LAYOUT

Make the object position-able by the layouts

enumerator LV_OBJ_FLAG_FLOATING

Do not scroll the object when the parent scrolls and ignore layout

enumerator LV_OBJ_FLAG_OVERFLOW_VISIBLE

Do not clip the children's content to the parent's boundary

enumerator LV_OBJ_FLAG_LAYOUT_1

Custom flag, free to use by layouts

enumerator LV_OBJ_FLAG_LAYOUT_2

Custom flag, free to use by layouts

enumerator LV_OBJ_FLAG_WIDGET_1

Custom flag, free to use by widget

enumerator LV_OBJ_FLAG_WIDGET_2

Custom flag, free to use by widget

enumerator LV_OBJ_FLAG_USER_1

Custom flag, free to use by user

enumerator LV_OBJ_FLAG_USER_2

Custom flag, free to use by user

enumerator LV_OBJ_FLAG_USER_3

Custom flag, free to use by user

enumerator LV_OBJ_FLAG_USER_4

Custom flag, free to use by user

enum lv_obj_draw_part_type_t

type field in lv_obj_draw_part_dsc_t if class_p = lv_obj_class Used in LV_EVENT_DRAW_PART_BEGIN and LV_EVENT_DRAW_PART_END

Values:

enumerator LV_OBJ_DRAW_PART_RECTANGLE

The main rectangle

enumerator LV_OBJ_DRAW_PART_BORDER_POST

The border if style_border_post = true

enumerator LV_OBJ_DRAW_PART_SCROLLBAR

The scrollbar

Functions

void lv_init(void)

Initialize LVGL library. Should be called before any other LVGL related function.

void lv_deinit(void)

Deinit the 'lv' library Currently only implemented when not using custom allocators, or GC is enabled.

bool lv_is_initialized(void)

Returns whether the 'lv' library is currently initialized

lv_obj_t *lv_obj_create(lv_obj_t *parent)

Create a base object (a rectangle)

参数

parent -- pointer to a parent object. If NULL then a screen will be created.

返回

pointer to the new object

void lv_obj_add_flag(lv_obj_t *obj, lv_obj_flag_t f)

Set one or more flags

参数

• obj -- pointer to an object

• f -- R-ed values from lv_obj_flag_t to set.

void lv_obj_clear_flag(lv_obj_t *obj, lv_obj_flag_t f)

Clear one or more flags

参数

• obj -- pointer to an object

• f -- OR-ed values from lv_obj_flag_t to set.

void lv_obj_add_state(lv_obj_t *obj, lv_state_t state)

Add one or more states to the object. The other state bits will remain unchanged. If specified in the styles, transition animation will be started from the previous state to the current.

参数

• obj -- pointer to an object

• state -- the states to add. E.g LV_STATE_PRESSED | LV_STATE_FOCUSED

void lv_obj_clear_state(lv_obj_t *obj, lv_state_t state)

Remove one or more states to the object. The other state bits will remain unchanged. If specified in the styles, transition animation will be started from the previous state to the current.

参数

• obj -- pointer to an object

• state -- the states to add. E.g LV_STATE_PRESSED | LV_STATE_FOCUSED

static inline void lv_obj_set_user_data(lv_obj_t *obj, void *user_data)

Set the user_data field of the object

参数

• obj -- pointer to an object

• user_data -- pointer to the new user_data.

bool lv_obj_has_flag(const lv_obj_t *obj, lv_obj_flag_t f)

Check if a given flag or all the given flags are set on an object.

参数

• obj -- pointer to an object

• f -- the flag(s) to check (OR-ed values can be used)

返回

true: all flags are set; false: not all flags are set

bool lv_obj_has_flag_any(const lv_obj_t *obj, lv_obj_flag_t f)

Check if a given flag or any of the flags are set on an object.

参数

• obj -- pointer to an object

• f -- the flag(s) to check (OR-ed values can be used)

返回

true: at lest one flag flag is set; false: none of the flags are set

lv_state_t lv_obj_get_state(const lv_obj_t *obj)

Get the state of an object

参数

obj -- pointer to an object

返回

the state (OR-ed values from lv_state_t)

bool lv_obj_has_state(const lv_obj_t *obj, lv_state_t state)

Check if the object is in a given state or not.

参数

• obj -- pointer to an object

• state -- a state or combination of states to check

返回

true: obj is in state; false: obj is not in state

void *lv_obj_get_group(const lv_obj_t *obj)

Get the group of the object

参数

obj -- pointer to an object

返回

the pointer to group of the object

static inline void *lv_obj_get_user_data(lv_obj_t *obj)

Get the user_data field of the object

参数

obj -- pointer to an object

返回

the pointer to the user_data of the object

void lv_obj_allocate_spec_attr(lv_obj_t *obj)

Allocate special data for an object if not allocated yet.

参数

obj -- pointer to an object

bool lv_obj_check_type(const lv_obj_t *obj, const lv_obj_class_t *class_p)

Check the type of obj.

参数

• obj -- pointer to an object

• class_p -- a class to check (e.g. lv_slider_class)

返回

true: class_p is the obj class.

bool lv_obj_has_class(const lv_obj_t *obj, const lv_obj_class_t *class_p)

Check if any object has a given class (type). It checks the ancestor classes too.

参数

• obj -- pointer to an object

• class_p -- a class to check (e.g. lv_slider_class)

返回

true: obj has the given class

const lv_obj_class_t *lv_obj_get_class(const lv_obj_t *obj)

Get the class (type) of the object

参数

obj -- pointer to an object

返回

the class (type) of the object

bool lv_obj_is_valid(const lv_obj_t *obj)

Check if any object is still "alive".

参数

obj -- pointer to an object

返回

true: valid

static inline lv_coord_t lv_obj_dpx(const lv_obj_t *obj, lv_coord_t n)

Scale the given number of pixels (a distance or size) relative to a 160 DPI display considering the DPI of the obj's display. It ensures that e.g. lv_dpx(100) will have the same physical size regardless to the DPI of the display.

参数

• obj -- an object whose display's dpi should be considered

• n -- the number of pixels to scale

返回

n x current_dpi/160

Variables

const lv_obj_class_t lv_obj_class

Make the base object's class publicly available.

struct _lv_obj_spec_attr_t

#include <lv_obj.h>

Special, rarely used attributes. They are allocated automatically if any elements is set.

Public Members

struct _lv_obj_t **children

Store the pointer of the children in an array.

uint32_t child_cnt

Number of children

lv_group_t *group_p

struct _lv_event_dsc_t *event_dsc

Dynamically allocated event callback and user data array

lv_point_t scroll

The current X/Y scroll offset

lv_coord_t ext_click_pad

Extra click padding in all direction

lv_coord_t ext_draw_size

EXTend the size in every direction for drawing.

lv_scrollbar_mode_t scrollbar_mode

How to display scrollbars

lv_scroll_snap_t scroll_snap_x

Where to align the snappable children horizontally

lv_scroll_snap_t scroll_snap_y

Where to align the snappable children vertically

lv_dir_t scroll_dir

The allowed scroll direction(s)

uint8_t event_dsc_cnt

Number of event callbacks stored in event_dsc array

struct _lv_obj_t

Public Members

const lv_obj_class_t *class_p

struct _lv_obj_t *parent

_lv_obj_spec_attr_t *spec_attr

_lv_obj_style_t *styles

void *user_data

lv_area_t coords

lv_obj_flag_t flags

lv_state_t state

uint16_t layout_inv

uint16_t scr_layout_inv

uint16_t skip_trans

uint16_t style_cnt

uint16_t h_layout

uint16_t w_layout