Distributes the height of the view port equally to each item. If the view port height needs to be measured, the largest item's height will be used for all items, subject to any specified minimum and maximum height values.

The default value is false.

Used internally by a component with grouped data to indicate which indices are headers for a group.

When the scroll position is calculated for a header (specified by a GroupedList or another component with the headerIndicies property, an attempt will be made to align the header to this position.

The default value is feathers.layout.VerticalAlign.TOP.

See also

The alignment of the items horizontally, on the x-axis.

If the horizontalAlign property is set to feathers.layout.HorizontalAlign.JUSTIFY, the width, minWidth, and maxWidth properties of the items may be changed, and their original values ignored by the layout. In this situation, if the width needs to be constrained, the width, minWidth, or maxWidth properties should instead be set on the parent container using the layout.

The default value is feathers.layout.HorizontalAlign.LEFT.

See also

The maximum number of rows to display. If the explicit height of the view port is set or if requestedRowCount is set, then this value will be ignored. If the view port's minimum and/or maximum height are set, the actual number of visible rows may be adjusted to meet those requirements. Set this value to 0 to display as many rows as possible.

The default value is 0.

Requests that the layout set the view port dimensions to display a specific number of rows (plus gaps and padding), if possible. If the explicit height of the view port is set, then this value will be ignored. If the view port's minimum and/or maximum height are set, the actual number of visible rows may be adjusted to meet those requirements. Set this value to 0 to display as many rows as possible.

The default value is 0.

See also

Determines if the container calls layout() when the scroll position changes. Useful for transforming items as the view port scrolls. This value should be true for layouts that implement the IVirtualLayout interface and the useVirtualLayout property is set to true. May also be used by layouts that toggle item visibility as the items scroll into and out of the view port.

When the scroll position is calculated for an item, an attempt will be made to align the item to this position.

The default value is feathers.layout.VerticalAlign.MIDDLE.

See also

If a non-null value for the headerIndices property is provided (by a component like GroupedList), and the stickyHeader property is set to true, a header will stick to the top of the view port until the current group completely scrolls out of the view port.

The default value is false.

If the total item height is less than the bounds, the positions of the items can be aligned vertically, on the y-axis.

Note: The VerticalAlign.JUSTIFY constant is not supported.

The default value is feathers.layout.VerticalAlign.TOP.

See also

Constructor.

Using the current index and a key press, calculates the new index. This might be use to change a list's selectedIndex when a key is pressed.

Parameters

Calculates the scroll position nearest to the current scroll position that will display the full bounds of the item within the view port. If the item is already fully displayed in the view port, the current scroll position will be returned unchanged.

While the item will be displayed in the view port without being clipped in any way, it may not be placed in the most prominent position possible. To give the item a more prominent location, use getScrollPositionForIndex() instead.

This function should always be called after the layout() function. The width and height arguments are the final bounds of the view port, which may be calculated in the layout() function.

Parameters

Using the item dimensions, calculates a scroll position that will ensure that the item at a given index will be visible within the specified bounds.

Typically, this function is used to show the item in the most prominent way, such as centering. To scroll a minimum distance required to display the full bounds of the item in the view port, use getNearestScrollPositionForIndex() instead.

This function should always be called after the layout() function. The width and height arguments are the final bounds of the view port, which may be calculated in the layout() function.

Parameters

Used internally by a component, such as List, to determines which indices are visible with the specified view port bounds and scroll position. Indices that aren't returned are typically not displayed and can be replaced virtually. Uses the typical items dimensions, or cached dimensions, if available.

This function is meant to be called by the List or other component that uses the virtual layout. If you're simply creating a layout for a List or another component, do not call this function. It is meant for developers creating custom components only.

Parameters

Positions (and possibly resizes) the supplied items within the optional bounds argument. If no bounds are specified, the layout algorithm will assume that the bounds start a 0,0 and have unbounded dimensions. Returns the actual bounds of the content, which may be different than the specified bounds.

Note: The items are not absolutely restricted to appear only within the bounds. The bounds can affect positioning, but the algorithm may very well ignore them completely.

If a layout implementation needs to access accurate width and height values from items that are of type IFeathersControl, it must call validate() manually. For performance reasons, the container that is the parent of the items will not call validate() before passing the items to a layout implementation. Meeting this requirement may be as simple as looping through the items at the beginning of layout() and validating all items that are Feathers UI controls:

const itemCount:int = items.length;
for(var i:int = 0; i < itemCount; i++)
{
    var item:IFeathersControl = items[i] as IFeathersControl;
    if(item)
    {
        item.validate();
    }
}

Parameters

Used internally by a component, such as List, to measure the view port based on the typical item dimensions or cached dimensions, if available.

This function is meant to be called by the List or other component that uses the virtual layout. If you're simply creating a layout for a List or another component, do not call this function. It is meant for developers creating custom components only.

Parameters