2022年6月22日 (水) 23:09時点における版

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).

Moving together

If the position of a parent changes, the children will move along with it. Therefore, all positions are relative to the parent.

lv_obj_t * parent = lv_obj_create(lv_scr_act());   /*Create a parent object on the current screen*/
lv_obj_set_size(parent, 100, 80);	                 /*Set the size of the parent*/

lv_obj_t * obj1 = lv_obj_create(parent);	         /*Create an object on the previously created parent object*/
lv_obj_set_pos(obj1, 10, 10);	                     /*Set the position of the new object*/

Modify the position of the parent:

lv_obj_set_pos(parent, 50, 50);	/*Move the parent. The child will move with it.*/

(For simplicity the adjusting of colors of the objects is not shown in the example.)

Visibility only on the parent If a child is partially or fully outside its parent then the parts outside will not be visible.

lv_obj_set_x(obj1, -30);	/*Move the child a little bit off the parent*/

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@@ 29行目: / 29行目: @@
 You can set/get these attributes with <code>lv_obj_set_...</code> and <code>lv_obj_get_...</code> functions. For example:
+<syntaxhighlight lang="C++" style="border: 1px dashed gray;">
   /*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*/
+</syntaxhighlight>
 To see all the available functions visit the Base object's documentation.
@@ 41行目: / 43行目: @@
 For these special attributes, every object type may have unique API functions. For example for a slider:
+<syntaxhighlight lang="C++" style="border: 1px dashed gray;">
   /*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)*/
+</syntaxhighlight>
 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'')
@@ 53行目: / 59行目: @@
 === Moving together ===
 If the position of a parent changes, the children will move along with it. Therefore, all positions are relative to the parent.
 [[file:LVGL docs overview objects 01.png|link=https://docs.lvgl.io/8.2/overview/object.html]]
 <syntaxhighlight lang="C++" style="border: 1px dashed gray;">
 lv_obj_t * parent = lv_obj_create(lv_scr_act());   /*Create a parent object on the current screen*/
@@ 61行目: / 69行目: @@
 lv_obj_set_pos(obj1, 10, 10);	                     /*Set the position of the new object*/
 </syntaxhighlight>
 Modify the position of the parent:
 [[file:LVGL docs overview objects 02.png|link=https://docs.lvgl.io/8.2/overview/object.html]]
 <syntaxhighlight lang="C++" style="border: 1px dashed gray;">
 lv_obj_set_pos(parent, 50, 50);	/*Move the parent. The child will move with it.*/
 </syntaxhighlight>
 (For simplicity the adjusting of colors of the objects is not shown in the example.)
 Visibility only on the parent
 If a child is partially or fully outside its parent then the parts outside will not be visible.
 [[file:LVGL docs overview objects 03.png|link=https://docs.lvgl.io/8.2/overview/object.html]]
 <syntaxhighlight lang="C++" style="border: 1px dashed gray;">
 lv_obj_set_x(obj1, -30);	/*Move the child a little bit off the parent*/
 </syntaxhighlight>
 :[[App:Library:LVGL:docs:Overview|戻る : Previous]]

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