The following example shows how you can control the horizontal and vertical gaps between buttons in a ButtonBar control in Flex by setting the verticalGap and horizontalGap styles.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/01/08/setting-horizontal-and-vertical-gaps-between-buttons-in-a-flex-buttonbar-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="horizontal"
verticalAlign="middle"
backgroundColor="white">
<mx:Array id="arr">
<mx:Object label="The" />
<mx:Object label="quick" />
<mx:Object label="brown" />
<mx:Object label="fox" />
</mx:Array>
<mx:ApplicationControlBar dock="true">
<mx:Form styleName="plain">
<mx:FormItem label="verticalGap:" direction="horizontal">
<mx:HSlider id="slider"
minimum="-2"
maximum="10"
value="0"
liveDragging="true"
snapInterval="1"
tickInterval="1" />
<mx:Label text="{slider.value}" />
</mx:FormItem>
</mx:Form>
</mx:ApplicationControlBar>
<mx:ButtonBar id="buttonBar"
dataProvider="{arr}"
verticalGap="{slider.value}"
direction="vertical" />
</mx:Application>
View source is enabled in the following example.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/01/08/setting-horizontal-and-vertical-gaps-between-buttons-in-a-flex-buttonbar-control/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="horizontal"
verticalAlign="middle"
backgroundColor="white">
<mx:Array id="arr">
<mx:Object label="The" />
<mx:Object label="quick" />
<mx:Object label="brown" />
<mx:Object label="fox" />
</mx:Array>
<mx:ApplicationControlBar dock="true">
<mx:Form styleName="plain">
<mx:FormItem label="horizontalGap:" direction="horizontal">
<mx:HSlider id="slider"
minimum="-2"
maximum="10"
value="0"
liveDragging="true"
snapInterval="1"
tickInterval="1" />
<mx:Label text="{slider.value}" />
</mx:FormItem>
</mx:Form>
</mx:ApplicationControlBar>
<mx:ButtonBar id="buttonBar"
dataProvider="{arr}"
horizontalGap="{slider.value}"
direction="horizontal" />
</mx:Application>
View source is enabled in the following example.
You could also set the horizontalGap or verticalGap style in an external .CSS file or <mx:Style /> block, as seen in the following snippet:
<mx:Style>
ButtonBar {
horizontalGap: 16;
}
</mx:Style>
Or, you can set the horizontalGap or verticalGap style using ActionScript, as seen in the following snippet:
<mx:Script>
<![CDATA[
private function init():void {
buttonBar.setStyle("horizontalGap", 16);
}
]]>
</mx:Script>





this was very helpful, thanks! i always forget that gaps are styles, not properties :-)