Spark TitleWindow's titlebar fontSize Change

While I was trying to change the fontSize of titlebar of TitleWindows, the whole container changes to new font Size. But I do not want to achive this. I would like to get it only on the titlebar.

The code I have used (not successful)

<s:TitleWindow name="MyTitleWindow"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library:开发者_如何学JAVA//ns.adobe.com/flex/mx"
        title="Search"
        width="1200"
        height="800"
        fontSize="24"
        preinitialize="preInit();"
        close="handleCloseEvent(event);" >

---
---
</s:TitleWindow>

I am using Flex4 and Spark.

I suggest you to create your own skin based on spark.skins.spark.TitleWindowSkin and change corresponding attributes of Label with id titleDisplay.

You can read more details about skinning in official documentation.

The sample skin for your window is the following (added just one attribute):

<?xml version="1.0" encoding="utf-8"?>
<s:SparkSkin xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" 
    xmlns:fb="http://ns.adobe.com/flashbuilder/2009" blendMode="normal" mouseEnabled="false"
    minWidth="76" minHeight="76" alpha.disabled="0.5" alpha.disabledWithControlBar="0.5">

    <fx:Metadata>
        <![CDATA[ 
        /** 
         * @copy spark.skins.spark.ApplicationSkin#hostComponent
         */
        [HostComponent("spark.components.TitleWindow")]
        ]]>
    </fx:Metadata> 

    <fx:Script fb:purpose="styling">
        <![CDATA[
        import mx.core.FlexVersion;

        /* Define the skin elements that should not be colorized. 
        For panel, border and title background are skinned, but the content area, background, border, and title text are not. */
        static private const exclusions:Array = ["background", "titleDisplay", "contentGroup", "border"];

        /* exclusions before Flex 4.5 for backwards-compatibility purposes */
        static private const exclusions_4_0:Array = ["background", "titleDisplay", "contentGroup"];

        /**
         * @private
         */
        override public function get colorizeExclusions():Array 
        {
            // Since border is styleable via borderColor, no need to allow chromeColor to affect
            // the border.  This is wrapped in a compatibility flag since this change was added  
            // in Flex 4.5
            if (FlexVersion.compatibilityVersion < FlexVersion.VERSION_4_5)
            {
                return exclusions_4_0;
            }

            return exclusions;
        }

        /**
         * @private
         */
        override protected function initializationComplete():void
        {
            useChromeColor = true;
            super.initializationComplete();
        }

        /**
         * @private
         */
        override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
        {
            if (getStyle("borderVisible") == true)
            {
                border.visible = true;
                background.left = background.top = background.right = background.bottom = 1;
                contents.left = contents.top = contents.right = contents.bottom = 1;
            }
            else
            {
                border.visible = false;
                background.left = background.top = background.right = background.bottom = 0;
                contents.left = contents.top = contents.right = contents.bottom = 0;
            }

            dropShadow.visible = getStyle("dropShadowVisible");

            var cr:Number = getStyle("cornerRadius");
            var withControls:Boolean = 
                (currentState == "disabledWithControlBar" || 
                 currentState == "normalWithControlBar" ||
                 currentState == "inactiveWithControlBar");

            if (cornerRadius != cr)
            {
                cornerRadius = cr;

                dropShadow.tlRadius = cornerRadius;
                dropShadow.trRadius = cornerRadius;
                dropShadow.blRadius = withControls ? cornerRadius : 0;
                dropShadow.brRadius = withControls ? cornerRadius : 0;

                setPartCornerRadii(topMaskRect, withControls); 
                setPartCornerRadii(border, withControls); 
                setPartCornerRadii(background, withControls);
            }

            if (bottomMaskRect) setPartCornerRadii(bottomMaskRect, withControls); 

            borderStroke.color = getStyle("borderColor");
            borderStroke.alpha = getStyle("borderAlpha");
            backgroundFill.color = getStyle("backgroundColor");
            backgroundFill.alpha = getStyle("backgroundAlpha");

            super.updateDisplayList(unscaledWidth, unscaledHeight);
        }

        /**
         * @private
         */  
        private function setPartCornerRadii(target:Rect, includeBottom:Boolean):void
        {            
            target.topLeftRadiusX = cornerRadius;
            target.topRightRadiusX = cornerRadius;
            target.bottomLeftRadiusX = includeBottom ? cornerRadius : 0;
            target.bottomRightRadiusX = includeBottom ? cornerRadius : 0;
        }

        private var cornerRadius:Number;
        ]]>
    </fx:Script>

    <s:states>
        <s:State name="normal" />
        <s:State name="inactive" stateGroups="inactiveGroup" />
        <s:State name="disabled" />
        <s:State name="normalWithControlBar" stateGroups="withControls" />
        <s:State name="inactiveWithControlBar" stateGroups="withControls, inactiveGroup" />
        <s:State name="disabledWithControlBar" stateGroups="withControls" />
    </s:states>

    <!--- drop shadow can't be hittable so it stays sibling of other graphics @private-->
    <s:RectangularDropShadow id="dropShadow" blurX="20" blurY="20" alpha="0.32" 
                             alpha.inactiveGroup="0.22" distance="11"  distance.inactiveGroup="7"
                             angle="90" color="0x000000" left="0" top="0" right="0" bottom="0"/>

    <!--- drop shadow can't be hittable so all other graphics go in this group -->
    <s:Group left="0" right="0" top="0" bottom="0">

        <!--- top group mask @private-->
        <s:Group left="1" top="1" right="1" bottom="1" id="topGroupMask">
            <!--- @private-->
            <s:Rect id="topMaskRect" left="0" top="0" right="0" bottom="0">
                <s:fill>
                    <s:SolidColor alpha="0"/>
                </s:fill>
            </s:Rect>
        </s:Group>

        <!--- bottom group mask @private-->
        <s:Group left="1" top="1" right="1" bottom="1" id="bottomGroupMask" 
                 includeIn="withControls">
            <!--- @private-->
            <s:Rect id="bottomMaskRect" left="0" top="0" right="0" bottom="0">
                <s:fill>
                    <s:SolidColor alpha="0"/>
                </s:fill>
            </s:Rect>
        </s:Group>

        <!--- layer 1: border @private -->
        <s:Rect id="border" left="0" right="0" top="0" bottom="0" >
            <s:stroke>
                <!--- Defines the TitleWindowSkin class's border stroke. The default value is 1. -->
                <s:SolidColorStroke id="borderStroke" weight="1" />
            </s:stroke>
        </s:Rect>

        <!-- layer 2: background fill -->
        <!--- Defines the appearance of the TitleWindowSkin class's background. -->
        <s:Rect id="background" left="1" top="1" right="1" bottom="1">
            <s:fill>
                <!--- Defines the TitleWindowSkin class's background fill. The default color is 0xFFFFFF. -->
                <s:SolidColor id="backgroundFill" color="#FFFFFF"/>
            </s:fill>
        </s:Rect>

        <!-- layer 3: contents -->
        <!--- Contains the vertical stack of title bar content and control bar. -->
        <s:Group left="1" right="1" top="1" bottom="1" id="contents">
            <s:layout>
                <s:VerticalLayout gap="0" horizontalAlign="justify" />
            </s:layout>
            <!--- @private -->
            <s:Group id="topGroup" mask="{topGroupMask}">

                <!--- layer 0: title bar fill @private -->
                <s:Rect id="tbFill" left="0" right="0" top="0" bottom="1">
                    <s:fill>
                        <s:LinearGradient rotation="90">
                            <s:GradientEntry color="0xD2D2D2"
                                             color.inactiveGroup="0xEAEAEA"/>
                            <s:GradientEntry color="0x9A9A9A"
                                             color.inactiveGroup="0xCECECE"/>
                        </s:LinearGradient>
                    </s:fill>
                </s:Rect>

                <!--- layer 1: title bar highlight @private -->
                <s:Rect id="tbHilite" left="0" right="0" top="0" bottom="0">
                    <s:stroke>
                        <s:LinearGradientStroke rotation="90" weight="1">
                            <s:GradientEntry color="0xE6E6E6" />
                            <s:GradientEntry color="0xFFFFFF" alpha="0.22"/>
                        </s:LinearGradientStroke>
                    </s:stroke>
                    <s:fill>
                        <s:LinearGradient rotation="90">
                            <s:GradientEntry color="0xFFFFFF" alpha="0.15" />
                            <s:GradientEntry color="0xFFFFFF" alpha="0.15" ratio="0.44"/>
                            <s:GradientEntry color="0xFFFFFF" alpha="0" ratio="0.4401"/>
                        </s:LinearGradient>
                    </s:fill>
                </s:Rect>

                <!--- layer 2: title bar divider @private -->
                <s:Rect id="tbDiv" left="0" right="0" height="1" bottom="0">
                    <s:fill>
                        <s:SolidColor color="0x000000" alpha="0.75" />
                    </s:fill>
                </s:Rect>

                <!-- layer 3: text -->
                <!--- @copy spark.components.Panel#titleDisplay -->
                <s:Label id="titleDisplay" maxDisplayedLines="1"
                         left="9" right="36" top="1" bottom="0" minHeight="30"
                         verticalAlign="middle" fontWeight="bold" fontSize="20" />

                <!-- layer 4: moveArea -->
                <!--- @copy spark.components.TitleWindow#moveArea -->
                <s:Group id="moveArea" left="0" right="0" top="0" bottom="0" />

                <!--- @copy spark.components.TitleWindow#closeButton -->
                <s:Button id="closeButton" skinClass="spark.skins.spark.TitleWindowCloseButtonSkin"
                          width="15" height="15" right="7" top="7" />
            </s:Group>

            <!--
                Note: setting the minimum size to 0 here so that changes to the host component's
                size will not be thwarted by this skin part's minimum size.   This is a compromise,
                more about it here: http://bugs.adobe.com/jira/browse/SDK-21143
            -->
            <!--- @copy spark.components.SkinnableContainer#contentGroup -->
            <s:Group id="contentGroup" width="100%" height="100%" minWidth="0" minHeight="0">
            </s:Group>

            <!--- @private -->
            <s:Group id="bottomGroup" minWidth="0" minHeight="0" 
                     includeIn="withControls">  

                <s:Group left="0" right="0" top="0" bottom="0" mask="{bottomGroupMask}">

                    <!-- layer 0: control bar divider line -->
                    <s:Rect left="0" right="0" top="0" height="1" alpha="0.22">
                        <s:fill>
                            <s:SolidColor color="0x000000" />
                        </s:fill>
                    </s:Rect>

                    <!-- layer 1: control bar highlight -->
                    <s:Rect left="0" right="0" top="1" bottom="0">
                        <s:stroke>
                            <s:LinearGradientStroke rotation="90" weight="1">
                                <s:GradientEntry color="0xFFFFFF" />
                                <s:GradientEntry color="0xD8D8D8" />
                            </s:LinearGradientStroke>
                        </s:stroke>
                    </s:Rect>

                    <!-- layer 2: control bar fill -->
                    <s:Rect left="1" right="1" top="2" bottom="1">
                        <s:fill>
                            <s:LinearGradient rotation="90">
                                <s:GradientEntry color="0xEDEDED"/>
                                <s:GradientEntry color="0xCDCDCD"/>
                            </s:LinearGradient>
                        </s:fill>
                    </s:Rect>
                </s:Group>

                <!--- @copy spark.components.Panel#controlBarGroup -->
                <s:Group id="controlBarGroup" left="0" right="0" top="1" bottom="1" minWidth="0" minHeight="0">
                    <s:layout>
                        <s:HorizontalLayout paddingLeft="10" paddingRight="10" paddingTop="7" paddingBottom="7" gap="10" />
                    </s:layout>
                </s:Group>
            </s:Group>
        </s:Group>
    </s:Group>
</s:SparkSkin>

You can apply it with external CSS file or directly in MXML:

<s:TitleWindow skinClass="MyTitleWindowSkin" />

Or in ActionScript:

myWindow.setStyle("skinClass", MyTitleWindowSkin);

I have managed the above issue by

<s:TitleWindow name="MyTitleWindow"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        xmlns:mx="library://ns.adobe.com/flex/mx"
        title="Search"
        width="600" height="800"
        creationComplete="complete();"  
        close="handleCloseEvent(event);">

----
----

Actionscript Part:

        private function complete():void {
            trace("Style" + this.titleDisplay.getStyle("fontSize")); 
            this.titleDisplay.setStyle("fontSize", "30");
        }

In this way I could change only the titleBar fontSize.

Hope it will help others.