Class WOverlayLoadingIndicator

All Implemented Interfaces:

public class WOverlayLoadingIndicator
extends WContainerWidget
implements WLoadingIndicator
A more obvious loading indicator that grays the window.

This loading indicator uses a gray semi-transparent overlay to darken the window contents, and centers a loading icon (with some text).

Usage example:

The overlay loading indicator

Note: For this loading indicator to render properly in IE, you need to reset the "body" margin to 0. Using the inline stylesheet, this could be done using:


This widget does not provide styling, and can be styled using inline or external CSS as appropriate.


The strings used in this class can be translated by overriding the default values for the following localization keys:

  • Wt.WOverlayLoadingIndicator.Loading: Loading...

See Also:
WApplication.setLoadingIndicator(WLoadingIndicator indicator)
  • Constructor Details

    • WOverlayLoadingIndicator

      public WOverlayLoadingIndicator​(java.lang.String styleClass, java.lang.String backgroundStyleClass, java.lang.String textStyleClass)
      Construct the loading indicator.

      styleClass - the style class for the central box
      backgroundStyleClass - the style class for the "background" part of the indicator
      textStyleClass - the style class for the text that is displayed

      Note: if styleClass is not set, the central box gets the CSS style elements

       background: white;
       border: 3px solid #333333;
       z-index: 10001; visibility: visible;
       position: absolute; left: 50%; top: 50%;
       margin-left: -50px; margin-top: -40px;
       width: 100px; height: 80px;
       font-family: arial,sans-serif;
       text-align: center

      Note: if backgroundStyleClass is not set, the background gets the CSS style elements

       background: #DDDDDD;
       height: 100%; width: 100%;
       top: 0px; left: 0px;
       z-index: 10000;
       -moz-background-clip: -moz-initial;
       -moz-background-origin: -moz-initial;
       -moz-background-inline-policy: -moz-initial;
       opacity: 0.5; filter: alpha(opacity=50); -moz-opacity:0.5;
       position: absolute;
    • WOverlayLoadingIndicator

      public WOverlayLoadingIndicator()
      Construct the loading indicator.

      Calls this("", "", "")

    • WOverlayLoadingIndicator

      public WOverlayLoadingIndicator​(java.lang.String styleClass)
      Construct the loading indicator.

      Calls this(styleClass, "", "")

    • WOverlayLoadingIndicator

      public WOverlayLoadingIndicator​(java.lang.String styleClass, java.lang.String backgroundStyleClass)
      Construct the loading indicator.

      Calls this(styleClass, backgroundStyleClass, "")

  • Method Details

    • getWidget

      public WWidget getWidget()
      Returns the widget that visually represents the indicator.

      You should reimplement this method to return a widget that will be shown to indicate that a response is pending. The widget should be positioned using CSS.

      The widget will be shown and hidden using and WWidget.hide(). If you want to customize this behaviour, you should reimplement the WWidget#setHidden() method. Note that and WWidget.hide() are stateless slots, and thus you need to make sure that your implementation comforms to that contract, so that it may be optimized to JavaScript (the server-side implementation will only be called during stateless slot prelearning).

      Note: The widget will not be added to the WApplication.getRoot() container.

      Specified by:
      getWidget in interface WLoadingIndicator
    • setMessage

      public void setMessage​(java.lang.CharSequence text)
      Description copied from interface: WLoadingIndicator
      Sets the message that you want to be displayed.

      If the indicator is capable of displaying a text message, then you should reimplement this method to allow this message to be modified.

      Specified by:
      setMessage in interface WLoadingIndicator