<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
    <mx:Script>
        <![CDATA[
        
            import flash.system.ApplicationDomain;
            
            private function loadImageHandler():void
            {
                var c:Class;
                if (ApplicationDomain.currentDomain.hasDefinition("SunnyImage"))
                {
                    c = Class(ApplicationDomain.currentDomain.getDefinition("SunnyImage"));
                    sunny.source = c;
                }
                else
                {
                    // ...............
                }
                
                                
                if (ApplicationDomain.currentDomain.hasDefinition("RainyImage"))
                {
                    c = Class(ApplicationDomain.currentDomain.getDefinition("RainyImage"));
                    rainy.source = c;
                }
                else
                {
                    // ...............
                }
            
            }
            
        ]]>
    </mx:Script>
    <mx:Image id="sunny" x="28" y="28"/>
    <mx:Image id="rainy" x="130" y="28"/>
    
    <mx:Button x="67" y="99" label="Load Images" click="loadImageHandler()"/>
    
</mx:Application>

package
{
    import flash.display.DisplayObject;
    import flash.display.MovieClip;
    import mx.core.BitmapAsset;
    
    [Embed(source="assets/sunny.png")]
    
    
    // this calss is linked onto the 3nd frame of systemManager.
    public class SunnyImage extends mx.core.BitmapAsset
    {
        //this method called by systemManager when systemManager's currentFrame == 3
        public static function frame(root:DisplayObject):void
        {
            if (root is MovieClip)
            {
                trace("currentFrame: " + MovieClip(root).currentFrame);
            }
        }
        
        public function SunnyImage()
        {
            super();
        }
    
    }

}

package
{
    import flash.display.DisplayObject;
    import flash.display.MovieClip;    
    import mx.core.BitmapAsset;
    
    [Embed(source="assets/rainy.png")]
    
    
    // this calss is linked onto the 4th frame of systemManager.
    public class RainyImage extends mx.core.BitmapAsset
    {
        
        //this method called by systemManager when systemManager's currentFrame == 4
        public static function frame(root:DisplayObject):void
        {
            if (root is MovieClip)
            {
                trace("currentFrame: " + MovieClip(root).currentFrame);
            }
        }
        
        public function RainyImage()
        {
            super();
        }
    
    }

}

<?xml version="1.0"?>  
  
   <flex-config>
    
       <frames>
            <frame>
                <label>Three</label>
                <classname>SunnyImage</classname>
            </frame>
            <frame>
                <label>Four</label>
                <classname>RainyImage</classname>
            </frame>
        </frames>
    </flex-config>

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
        
    <mx:Canvas id="canvas" x="10" y="10" width="200" height="200"
        rollOver="trace('in')" rollOut="trace('out')" />
        
</mx:Application>

1，<mx:Canvas id="canvas" x="10" y="10" width="200" height="200"
        rollOver="trace('in')" rollOut="trace('out')" backgroundAlpha="0" backgroundColor="#ff000"/>

2，<mx:Canvas id="canvas" x="10" y="10" width="200" height="200"
        rollOver="trace('in')" rollOut="trace('out')"
        preinitialize="canvas.setStyle('mouseShield', true);"/>

border = new mx.skins.halo.HaloBorder();
// Add the border behind all the children.
rawChildren.addChildAt(DisplayObject(border), 0);

global
{
    backgroundAlpha: 1.0; /* this runs the opacity of nearly every square piece of the components */
    /* backgroundDisabledColor: #DDDDDD; */
    backgroundSize: "auto";
    bevel: true;
    borderAlpha: 1.0;
      borderCapColor: #919999;
    borderColor: #B7BABC;
    borderSides: "left top right bottom";
    borderSkin: ClassReference("mx.skins.halo.HaloBorder");
    borderStyle: "inset";
    borderThickness: 1;
        ...........
}

Container
{
    borderStyle: "none";
}

/**
     *  @private
     *  Create components that are children of this Container.
     */
    override protected function createChildren():void
    {
        super.createChildren();

        // Create the border/background object.
        createBorder();

        // To save ourselves an extra layout pass, check to see
        // if the scrollbars will definitely be needed.
        // If so, create them now.
        createOrDestroyScrollbars(
            horizontalScrollPolicy == ScrollPolicy.ON,
            verticalScrollPolicy == ScrollPolicy.ON,
            horizontalScrollPolicy == ScrollPolicy.ON ||
            verticalScrollPolicy == ScrollPolicy.ON);

        // Determine the child-creation policy (ContainerCreationPolicy.AUTO,
        // ContainerCreationPolicy.ALL, or ContainerCreationPolicy.NONE).
        // If the author has specified a policy, use it.
        // Otherwise, use the parent's policy.
        // This must be set before createChildren() gets called.
        if (creationPolicy != null)
        {
            actualCreationPolicy = creationPolicy;
        }
        else if (parent is Container)
        {
            if (Container(parent).actualCreationPolicy ==
                ContainerCreationPolicy.QUEUED)
            {
                actualCreationPolicy = ContainerCreationPolicy.AUTO;
            }
            else
            {
                actualCreationPolicy = Container(parent).actualCreationPolicy;
            }
        }

        // It is ok for actualCreationPolicy to be null. Popups require it.

        if (actualCreationPolicy == ContainerCreationPolicy.NONE)
        {
            actualCreationPolicy = ContainerCreationPolicy.AUTO;
        }
        else if (actualCreationPolicy == ContainerCreationPolicy.QUEUED)
        {
            var mainApp:Application = parentApplication ?
                                      Application(parentApplication) :
                                      Application(Application.application);
            
            mainApp.addToCreationQueue(this, creationIndex, null, this);
        }
        else if (recursionFlag)
        {
            // Create whatever children are appropriate. If any were
            // previously created, they don't get re-created.
            createComponentsFromDescriptors();
        }

        // If autoLayout is initially false, we still want to do
        // measurement once (even if we don't have any children)
        if (autoLayout == false)
            forceLayout = true;

        // weak references
        UIComponentGlobals.layoutManager.addEventListener(
            FlexEvent.Update_COMPLETE, layoutCompleteHandler, false, 0, true);
    }

/**
     *  Creates the container's border skin
     *  if it is needed and does not already exist.
     */
    protected function createBorder():void
    {
        if (!border && isBorderNeeded())
        {
            var borderClass:Class = getStyle("borderSkin");

            if (borderClass != null)
            {
                border = new borderClass();
                border.name = "border";

                if (border is IUIComponent)
                    IUIComponent(border).enabled = enabled;
                if (border is ISimpleStyleClient)
                    ISimpleStyleClient(border).styleName = this;

                // Add the border behind all the children.
                rawChildren.addChildAt(DisplayObject(border), 0);

                invalidateDisplayList();
            }
        }
    }

    /**
     *  @private
     */
    private function isBorderNeeded():Boolean
    {
        //trace("isBorderNeeded",this,"ms",getStyle("mouseShield"),"borderStyle",getStyle("borderStyle"));

        // If the borderSkin is a custom class, always assume the border is needed.
        var c:Class = getStyle("borderSkin");
        
        // Lookup the HaloBorder class by name to avoid a linkage dependency.
        // Note: this code assumes HaloBorder is the default border skin. If this is changed
        // in defaults.css, it must also be changed here.
        try
        {
            if (c != getDefinitionByName("mx.skins.halo::HaloBorder"))
                return true;
        }
        catch(e:Error)
        {
            return true;
        }
            
        var v:Object = getStyle("borderStyle");
        if (v)
        {
            // If borderStyle is "none", then only create a border if the mouseShield style is true
            // (meaning that there is a mouse event listener on this view). We don't create a border
            // if our parent's mouseShieldChildren style is true.
            if ((v != "none") || (v == "none" && getStyle("mouseShield")))
            {
                return true;
            }
        }

        v = getStyle("backgroundColor");
        if (v !== null && v !== "")
            return true;

        v = getStyle("backgroundImage");
        return v != null && v != "";
    }

override public function styleChanged(styleProp:String):void
    {
        var allStyles:Boolean = styleProp == null || styleProp == "styleName";

        // Check to see if this is one of the style properties that is known
        // to affect page layout.
        if (allStyles || StyleManager.isSizeInvalidatingStyle(styleProp))
        {
            // Some styles, such as horizontalAlign and verticalAlign,
            // affect the layout of this object's children without changing the
            // view's size.  This function forces the view to be remeasured
            // and layed out.
            invalidateDisplayList();
        }

        // Replace the borderSkin
        if (allStyles || styleProp == "borderSkin")
        {
            if (border)
            {
                rawChildren.removeChild(DisplayObject(border));
                border = null;
                createBorder();
            }
        }
        
        // Create a border object, if none previously existed and
        // one is needed now.
        if (allStyles ||
            styleProp == "borderStyle" ||
            styleProp == "backgroundColor" ||
            styleProp == "backgroundImage" ||
            styleProp == "mouseShield" ||
            styleProp == "mouseShieldChildren")
        {
            createBorder();
        }

        super.styleChanged(styleProp);

        // Check to see if this is one of the style properties that is known.
        // to affect page layout.
        if (allStyles ||
            StyleManager.isSizeInvalidatingStyle(styleProp))
        {
            invalidateViewMetricsAndPadding();
        }

        if (allStyles || styleProp == "horizontalScrollBarStyleName")
        {
            if (horizontalScrollBar && horizontalScrollBar is ISimpleStyleClient)
            {
                var horizontalScrollBarStyleName:String =
                    getStyle("horizontalScrollBarStyleName");
                ISimpleStyleClient(horizontalScrollBar).styleName =
                    horizontalScrollBarStyleName;
            }
        }

        if (allStyles || styleProp == "verticalScrollBarStyleName")
        {
            if (verticalScrollBar && verticalScrollBar is ISimpleStyleClient)
            {
                var verticalScrollBarStyleName:String =
                    getStyle("verticalScrollBarStyleName");
                ISimpleStyleClient(verticalScrollBar).styleName =
                    verticalScrollBarStyleName;
            }
        }
    }

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="absolute" creationComplete="completeHandler()">
    <mx:Script>
        <![CDATA[
            import mx.controls.Button;
            import flash.utils.ByteArray;

            public function clone(source:Object):*
            {
                var myBA:ByteArray = new ByteArray();
                myBA.writeObject(source);
                myBA.position = 0;
                return(myBA.readObject());
            }
            
            
            private var c1:CloneClass;
            private var c2:Object;
            
            private function completeHandler():void
            {
                c1 = new CloneClass();
                c1.age = 30;
                c1.button = new Button;
                c1.button.label = "c1";
                
                c2 = clone(c1);
                trace("c1: " + c1.age + "  " + c1.button.label); // 输出 c1: 30  c1
                trace("c2: " + c2.age + "  " + c2.button.label); // 输出 c2: 30  c1
            }
            
            private function change():void
            {
                c1.age = 50;
                c1.button.label = "cc1";
                trace("after changed --------------------------------");
                trace("c1: " + c1.age + "  " + c1.button.label); // 输出 c1: 50  cc1
                trace("c2: " + c2.age + "  " + c2.button.label); // 输出 c2: 30  c1
            }
            
        ]]>
    </mx:Script>
    <mx:Button x="106" y="97" label="Change" click="change()"/>
        
</mx:Application>

package
{
    import mx.controls.Button;
    
    public class CloneClass
    {
        public var button:Button;
        public var age:uint = 1;
        
        
        public function CloneClass()
        {
        }

    }
}

<mx:Canvas id="myCanvas">
    <mx:Vbox id="box" x="0" y="10" width="200">
        <mx:Label id="text1" text="@Resource(key='name', bundle='test')" color="#ff0000"/>
        <mx:Label id="text2" text="@Resource(key='age', bundle='test')" styleName="ageLabel"/>
        <mx:Label id="text3" text="@Resource(key='sex', bundle='test')"/>
        <mx:Label id="text4" text="{resourceManager.getString('test', 'sex')}"/>
    </mx:Vbox>
    <mx:Button id="myBtn" x="27" y="100" label="change" click="changeHandler(event)"/>    
</mx:Canvas>  

override public function styleChanged(styleProp:String):void
{
    // 方法体
}

/**
     *  Detects changes to style properties. When any style property is set,
     *  Flex calls the <code>styleChanged()</code> method,
     *  passing to it the name of the style being set.
     *
     *  <p>This is an advanced method that you might override
     *  when creating a subclass of UIComponent. When you create a custom component,
     *  you can override the <code>styleChanged()</code> method
     *  to check the style name passed to it, and handle the change accordingly.
     *  This lets you override the default behavior of an existing style,
     *  or add your own custom style properties.</p>
     *
     *  <p>If you handle the style property, your override of
     *  the <code>styleChanged()</code> method should call the
     *  <code>invalidateDisplayList()</code> method to cause Flex to execute
     *  the component's <code>updateDisplayList()</code> method at the next screen update.</p>
     *
     *  @param styleProp The name of the style property, or null if all styles for this
     *  component have changed.
     */
    public function styleChanged(styleProp:String):void
    {
        // If font changed, then invalidateProperties so
        // we can re-create the text field in commitProperties
        if (this is IFontContextComponent && hasFontContextChanged())
            invalidateProperties();
        
        // Check to see if this is one of the style properties
        // that is known to affect layout.

        If (!styleProp ||
            styleProp == "styleName" ||
            StyleManager.isSizeInvalidatingStyle(styleProp))
        {
            // This style property change may affect the layout of this
            // object. Signal the LayoutManager to re-measure the object.
            invalidateSize();
        }

        if (!styleProp ||
            styleProp == "styleName" ||
            styleProp == "themeColor")
        {
            initThemeColor();
        }
        
        invalidateDisplayList();

        if (parent is Iinvalidating)
        {
            if (StyleManager.isParentSizeInvalidatingStyle(styleProp))
                Iinvalidating(parent).invalidateSize();

            if (StyleManager.isParentDisplayListInvalidatingStyle(styleProp))
                Iinvalidating(parent).invalidateDisplayList();
        }
    }

播放头前进到第二桢，docFrameHandler 函数开始执行。
首先会执行很多Singleton.registerClass方法，然后执行有[Mixin]元标签的类的
public static function init(fbs:IFlexModuleFactory):void 方法

"_alertButtonStyleStyle", "_ScrollBarStyle",
"_activeTabStyleStyle", "_textAreaHScrollBarStyleStyle",
"_ToolTipStyle", "_advancedDataGridStylesStyle",
"_comboDropdownStyle", "_comboDropDownStyle",
"_ContainerStyle", "_textAreaVScrollBarStyleStyle",
"_linkButtonStyleStyle", "_globalStyle", "_windowStatusStyle",
"_windowStylesStyle", "_activeButtonStyleStyle",
"_errorTipStyle", "_richTextEditorTextAreaStyleStyle",
"_CursorManagerStyle", "_todayStyleStyle", "_dateFieldPopupStyle",
"_plainStyle", "_dataGridStylesStyle", "_ApplicationStyle",
"_headerDateTextStyle", "_ButtonStyle", "_VScrollBarStyle",
"_popUpMenuStyle", "_swatchPanelTextFieldStyle",
"_opaquePanelStyle", "_weekDayStyleStyle", "_headerDragProxyStyleStyle"

package
{

import flash.display.Sprite;
import mx.core.IFlexModuleFactory;
import mx.core.mx_internal;
import mx.styles.CSSStyleDeclaration;
import mx.styles.StyleManager;
import mx.skins.halo.ButtonSkin;

[ExcludeClass]

public class _ButtonStyle
{

    public static function init(fbs:IFlexModuleFactory):void
    {
        var style:CSSStyleDeclaration = StyleManager.getStyleDeclaration("Button");
    
        if (!style)
        {
            style = new CSSStyleDeclaration();
            StyleManager.setStyleDeclaration("Button", style, false);
        }
    
        if (style.defaultFactory == null)
        {
            style.defaultFactory = function():void
            {
                this.paddingTop = 2;
                this.textAlign = "center";
                this.skin = mx.skins.halo.ButtonSkin;
                this.paddingLeft = 10;
                this.fontWeight = "bold";
                this.cornerRadius = 4;
                this.paddingRight = 10;
                this.verticalGap = 2;
                this.horizontalGap = 2;
                this.paddingBottom = 2;
            };
        }
    }
}

}

Button
{
    cornerRadius: 8;
}

.flashshe
{
    color: #ff0000;
}

package
{

import flash.display.Sprite;
import mx.core.IFlexModuleFactory;
import mx.core.mx_internal;
import mx.styles.CSSStyleDeclaration;
import mx.styles.StyleManager;

[ExcludeClass]

public class _FlashsheStyle
{

    public static function init(fbs:IFlexModuleFactory):void
    {
        var style:CSSStyleDeclaration = StyleManager.getStyleDeclaration(".flashshe");
    
        if (!style)
        {
            style = new CSSStyleDeclaration();
            StyleManager.setStyleDeclaration(".flashshe", style, false);
        }
    
        if (style.defaultFactory == null)
        {
            style.defaultFactory = function():void
            {
                this.color = 0xff0000;
            };
        }
    }
}

}

addingChild(child);
$addChildAt(child, index);
childAdded(child);

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
    layout="absolute" xmlns:ns1="*">
    
    <mx:Style source="one.css"/>
    <mx:Style>
        .myBtn
        {
            color: #00ff00;
            fontSize: 14;    
        }
    </mx:Style>
    <!--  MyButton 组件 从 Button 继承 -->
    <ns1:MyButton　id="testBtn" x="27" y="200" color="#0000ff" styleName="myBtn"/>
    
</mx:Application>

/* one.css */

Button
{
    color: #ff0000;
}

MyButton
{
    fontWeight: 16;
}

stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP_LEFT;

stop();

if (root && root.loaderInfo)
root.loaderInfo.addEventListener(Event.INIT, initHandler);

preloader = new Preloader();
preloader.addEventListener(FlexEvent.INIT_PROGRESS, preloader_initProgressHandler);
preloader.addEventListener(FlexEvent.PRELOADER_DONE, preloader_preloaderDoneHandler);

preloader.initialize(
usePreloader,
preloaderDisplayClass,
preloaderBackgroundColor,
preloaderBackgroundAlpha,
preloaderBackgroundImage,
preloaderBackgroundSize,
isStageRoot ? Stage.stageWidth : loaderInfo.width,
isStageRoot ? Stage.stageHeight : loaderInfo.height,
null,
null,
rslList,
resourceModuleURLs);
}

dispatchEvent(new Event(Event.COMPLETE));
dispatchEvent(new FlexEvent(FlexEvent.INIT_PROGRESS));

private function preloader_initProgressHandler(event:Event):void
{
// Advance the next frame
preloader.removeEventListener(FlexEvent.INIT_PROGRESS, preloader_initProgressHandler);

deferredNextFrame();
}

public static function init(fbs:IFlexModuleFactory):void

document = app = topLevelWindow = IUIComponent(create());

addingChild(DisplayObject(app));
// calls app.createChildren()
childAdded(DisplayObject(app));

// Add the mouseCatcher as child 0.
mouseCatcher = new FlexSprite();
mouseCatcher.name = "mouseCatcher";
// Must use addChildAt because a creationComplete handler can create a
// dialog and insert it at 0.
//noTopMostIndex++;
super.addChildAt(mouseCatcher, 0);

super.addChildAt(DisplayObject(app), 1);