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Shadow dwc-splitter
Java API

The Splitter component, designed to divide and resize content within your app, encapsulates two resizable components, the master and the detail components. A divider separates these components, allowing users to dynamically adjust each component's size according to their preferences.

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Besides its default constructor, the Splitter offers these constructors:

  • public Splitter(String id, Component master, Component detail): This constructor creates a Splitter instance with a specified ID, master component, and detail component.

  • public Splitter(Component master, Component detail): This constructor acts as a shorthand version of the previous one, creating a Splitter. without specifying an ID.

  • public Splitter(String id): This constructor allows you to create a Splitter instance with a specified ID.

Min and max size

The Splitter component provides methods to set min and max sizes for its panels, allowing developers to control the resizing behavior of the components within the Splitter. When users attempt to resize panels beyond the specified min or max sizes, the splitter component enforces these constraints, ensuring that panels remain within the defined boundaries.

Setting sizes

The setMasterMinSize(String masterMinSize) method specifies the min size for the master panel of the splitter. Likewise, the setMasterMaxSize(String masterMaxSize) method allows developers to define the max size for the master panel.

You can specify sizes using various units like pixels or other valid CSS units, as shown below:

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Developers can configure orientation in the Splitter component, allowing to create layouts tailored to specific design requirements. By specifying the orientation, the component arranges panels horizontally or vertically, providing versatility in layout design.

To configure the orientation use the supported orientations Enum to specify whether the Splitter should render horizontally or vertically:

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Relative position

To set the initial position of the divider bar in the Splitter component, use the setPositionRelative. This method takes a numeric value from 0 to 100 representing the percentage of the given space in the Splitter, and displays the divider at the given percentage of total width:

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Splitters nesting allow developers to create complex layouts with levels of resizable panels. It enables the creation of sophisticated user interfaces with granular control over the arrangement and resizing of content.

To nest Splitter components, instantiate new Splitter instances and add them as children to existing Splitter components. This hierarchical structure allows for the creation of multi-level layouts with flexible resizing capabilities. The program below demonstrates this:

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Auto save

The Splitter component includes an AutoSave option, which saves the state of panel sizes to local storage to keep dimensions consistent between reloads.

When you set the auto-save configuration, the Splitter component automatically stores the state of panel sizes in the web browser's local storage. This ensures that the sizes users choose for panels persist across page reloads or browser sessions, reducing the need for manual adjustments.

Cleaning the state

To programmatically remove the saved state to revert the Splitter back to default settings/dimensions, call the cleanState() method to remove any saved state data related to the Splitter component from the local storage of the web browser.

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In the preceding demo, each Splitter instance activates the AutoSave feature by calling the setAutosave method. This ensures the automatic saving of panel sizes to local storage. Thus, when reloading the browser, the sizes of these splitters remain constant.

Clicking the "Clear State" button calls the cleanState() method and refreshes the browser window to display the original dimensions.


Shadow parts

These are the various parts of the shadow DOM for the component, necessary for styling via CSS.



These are the available slots within the Splitter component. These slots serve as placeholders, guiding the insertion of customized element children into the shadow tree.


Reflected attributes

The component's reflected attributes appear as attributes in the rendered HTML element within the DOM, allowing for styling based on these attributes.



This component relies on the following components - see the related article for more detailed styling information:


Best practices

To ensure an optimal user experience when using the Splitter component, consider the following best practices:

  • Adjust Based on Content: When deciding on the orientation and initial sizes of panels, consider the content's priority. For example, in a layout with a navigation sidebar and a main content area, the sidebar should typically remain narrower with a set min size for clear navigation.

  • Strategic Nesting: Nesting splitters can create versatile layouts but can complicate the UI and impact performance. Plan your nested layouts to ensure they're intuitive and enhance user experience.

  • Remember User Preferences: Use the AutoSave feature to remember user adjustments across sessions, enhancing the user experience. Provide an option to allow users to reset to default settings.