https://docs.lvgl.io/8.2/overview/object.html

英文	自動翻訳

Objects

In LVGL the basic building blocks of a user interface are the objects, also called Widgets. For example a Button, Label, Image, List, Chart or Text area.

You can see all the Object types here.

All objects are referenced using an lv_obj_t pointer as a handle. This pointer can later be used to set or get the attributes of the object.

Attributes

Basic attributes

All object types share some basic attributes:

Position
Size
Parent
Styles
Event handlers
Etc

You can set/get these attributes with lv_obj_set_... and lv_obj_get_... functions. For example:

/*Set basic object attributes*/
lv_obj_set_size(btn1, 100, 50);	  /*Set a button's size*/
lv_obj_set_pos(btn1, 20,30);      /*Set a button's position*/

To see all the available functions visit the Base object's documentation.

Specific attributes

The object types have special attributes too. For example, a slider has

Minimum and maximum values
Current value

For these special attributes, every object type may have unique API functions. For example for a slider:

/*Set slider specific attributes*/
lv_slider_set_range(slider1, 0, 100);	   				/*Set the min. and max. values*/
lv_slider_set_value(slider1, 40, LV_ANIM_ON);		/*Set the current value (position)*/

The API of the widgets is described in their Documentation but you can also check the respective header files (e.g. widgets/lv_slider.h)

Working mechanisms

Parent-child structure

A parent object can be considered as the container of its children. Every object has exactly one parent object (except screens), but a parent can have any number of children. There is no limitation for the type of the parent but there are objects which are typically a parent (e.g. button) or a child (e.g. label).