UXML element Button

Use the Button element to create clickable buttons in a UI. For example, when a user clicks or taps on a Button element, it triggers an action or event, such as opening a new window, submitting a form, or playing a sound effect.

Create a Button

You can create a Button with UI Builder, UXML, or C#. The following C# example creates a Button with a label:

var button = new Button(() => { Debug.Log("Button clicked"); }) { text = "Click me" };

Add an icon to a Button

You can enhance the visual appeal of your Button by incorporating an icon, such as a Texture, Render Texture, Sprite, or Vector image asset that exists in your project. For information on how to reference an image asset, refer to Assets.

To add an icon for a Button with UI Builder:

• From the Button’s Inspector tab, choose the desired icon from the Icon Image dropdown list.
• Alternatively, drag the icon from the Assets window to the Icon Image field located in the Button’s Inspector tab.

To add an icon for a Button with UXML, provide the image source to the icon-image attribute:

<ui:Button name="Button" text="Button text" icon-image="/path/to/image-file.png" />

To add an icon for a Button with C#, assign the image source to the iconImage property:

Button myButton = new Button();
var buttonIconImage = Resources.Load<Texture2D>("image-file");

myButton.text = "Button text";
myButton.iconImage = buttonIconImage;

Change the Button icon position

When you add an icon to a Button, it adds two read-only sub-elements to the Button:

• An Image element to define the icon image.
• A TextElement to define the button text.

You can’t edit the sub-elements but you can change their layout using the USS flex-direction property for the Button element. By default, the icon is added on the left of the button text.

To reposition the button icon, adjust the Button’s flex-direction with the following:

• To shift the icon to the right of the button text, set it to row-reverse.
• To move the icon above the button text, set it to column.
• To place the icon below the button text, set it to column-reverse.

Use sub-elements of a Button

The Button element allows you to provide additional information to the user with the text, iconImage properties, and the background-image style property. As with any visual element, you can also add sub-elements in a Button’s hierarchy, such as a Label or Image, to provide additional information to the user if you want to have more fine-grained control over the appearance and behavior of those elements.

In general, use sub-elements in the following situations:

• Customization: Using sub-elements allows you to customize the appearance and behavior of each individual element separately. For example, you may want to use a custom font or color for the label text or add a specific animation to the image. When you add an Image element to your Button, you can add the element from your scene directly. In addition, an Image element also supports scale mode and repeat mode.
• Dynamic content: If the content of the label or image is dynamic, using sub-elements allows you to update the content of each element separately without affecting the other properties of the button.
• Interaction: If you want to add interactivity to a specific element within the button, such as allowing the user to click only the label (disregarding clicks on other elements of the button) to trigger an action, using sub-elements makes this possible.

Use properties for the following purposes:

• Simple designs: If the design of the button is simple and doesn’t require customization or dynamic content, using properties is recommended.
• Performance: If you have many buttons in your UI, using sub-elements for each one may negatively impact performance. In this case, it’s more efficient to use properties to set the appearance of the button.
• Consistency: If you want to maintain consistency across your UI, using properties can ensure that all buttons have a consistent appearance and behavior.

示例

The following UXML example creates a Button:

[!code-xml[(External/Resources/editor_resources/Assets/Editor Default Resources/UIPackageResources/Snippets/UXML/ButtonSnippet.uxml)]

The following C# example illustrates some of the customizable functionalities of the Button:

[!code-cs[(Modules/UIElementsSamplesEditor/Snippets/ButtonSnippet.cs#sample)]

To try this example live in Unity, go to Window > UI Toolkit > Samples.

C# base class and namespace

C# class: Button
Namespace: UnityEngine.UIElements
Base class: TextElement

Member UXML attributes

This element has the following member attributes:

名称	类型	描述
icon-image	Object	The Texture, Sprite, or VectorImage that will represent an icon within a Button element.

Inherited UXML attributes

This element inherits the following attributes from its base class:

名称	类型	描述
binding-path	string	Path of the target property to be bound.
display-tooltip-when-elided	boolean	When true, a tooltip displays the full version of elided text, and also if a tooltip had been previously provided, it will be overwritten.
emoji-fallback-support	boolean	Specifies the order in which the system should look for Emoji characters when rendering text. If this setting is enabled, the global Emoji Fallback list will be searched first for characters defined as Emoji in the Unicode 14.0 standard.
enable-rich-text	boolean	When false, rich text tags will not be parsed.
focusable	boolean	True if the element can be focused.
parse-escape-sequences	boolean	Specifies whether escape sequences are displayed as is or if they are replaced by the character they represent.
tabindex	int	An integer used to sort focusables in the focus ring. Must be greater than or equal to zero.
text	string	The text to be displayed. Changing this value will implicitly invoke the INotifyValueChanged_1.value setter, which will raise a ChangeEvent_1 of type string.

This element also inherits the following attributes from VisualElement:

名称	类型	描述
content-container	string	Child elements are added to it, usually this is the same as the element itself.
data-source	Object	Assigns a data source to this VisualElement which overrides any inherited data source. This data source is inherited by all children.
data-source-path	string	Path from the data source to the value.
name	string	The name of this VisualElement. Use this property to write USS selectors that target a specific element. The standard practice is to give an element a unique name.
picking-mode	UIElements.PickingMode	Determines if this element can be pick during mouseEvents or IPanel.Pick queries.
style	string	Reference to the style object of this element. Contains data computed from USS files or inline styles written to this object in C#.
tooltip	string	Text to display inside an information box after the user hovers the element for a small amount of time. This is only supported in the Editor UI.
usage-hints	UIElements.UsageHints	A combination of hint values that specify high-level intended usage patterns for the VisualElement. This property can only be set when the VisualElement is not yet part of a Panel. Once part of a Panel, this property becomes effectively read-only, and attempts to change it will throw an exception. The specification of proper UsageHints drives the system to make better decisions on how to process or accelerate certain operations based on the anticipated usage pattern. Note that those hints do not affect behavioral or visual results, but only affect the overall performance of the panel and the elements within. It’s advised to always consider specifying the proper UsageHints, but keep in mind that some UsageHints might be internally ignored under certain conditions (e.g. due to hardware limitations on the target platform).
view-data-key	string	Used for view data persistence, such as tree expanded states, scroll position, or zoom level. This key is used to save and load the view data from the view data store. If you don’t set this key, the persistence is disabled for the associated VisualElement. For more information, refer to View data persistence.

USS classes

The following table lists all the C# public property names and their related USS selector.

C# property	USS selector	描述
ussClassName	.unity-button	USS class name of elements of this type. Unity adds this USS class to every instance of the Button element. Any styling applied to this class affects every button located beside, or below the stylesheet in the visual tree.
iconUssClassName	.unity-button--with-icon	The USS class name for Button elements with an icon. Unity adds this USS class to an instance of the Button element if the instance’s Button.iconImage property contains a valid Texture. Any styling applied to this class affects every button with an icon located beside, or below the stylesheet in the visual tree.
ussClassName	.unity-text-element	USS class name of elements of this type.
selectableUssClassName	.unity-text-element__selectable	USS class name of selectable text elements.
disabledUssClassName	.unity-disabled	USS class name of local disabled elements.

You can also use the Matching Selectors section in the Inspector or the UI Toolkit Debugger to see which USS selectors affect the components of the VisualElement at every level of its hierarchy.

其他资源

• UXML element Image
• UXML element TextElement
• UXML element ToggleButtonGroup