（转）Flex 3 与 Flex 4 beta 之间的区别
http://www.soave.cn/post/2009/11/02/flex3and4_differences.aspx
http://www.adobe.com/cn/devnet/flex/articles/flex3and4_differences_04.html
【新增组件和容器】
Flex 4 beta 引入了许多使用新架构的新组件类，它们应当可以令外观和其他自定义操作更简单。下表列出了 Flex 3 Halo 组件及其 Flex 4 beta Spark 对应组件：
Flex 3 Halo 组件Flex 4 beta Spark 组件mx.controls.Buttonspark.components.Buttonmx.controls.ButtonBarspark.components.ButtonBarmx.controls.CheckBoxspark.components.CheckBoxmx.controls.ComboBoxspark.components.DropDownList（不可编辑）mx.controls.HorizontalListspark.components.List（带一个 HorizontalLayout）mx.controls.HRulespark.primitives.Linemx.controls.HScrollBarspark.components.HScrollBarmx.controls.HSliderspark.components.HSlidermx.controls.Imagespark.primitives.BitmapImagemx.controls.LinkBarspark.components.ButtonBar（带一个自定义外观）mx.controls.LinkButtonspark.components.Button（带一个自定义外观）mx.controls.Listspark.components.Listmx.controls.NumericStepperspark.components.NumericSteppermx.controls.RadioButtonspark.components.RadioButtonmx.controls.RadioButtonGroupspark.components.RadioButtonGroupmx.controls.TextAreaspark.components.TextAreamx.controls.TextInputspark.components.TextInputmx.controls.TileListspark.components.List（带一个 TileLayout）mx.controls.ToggleButtonBarspark.components.ButtonBarmx.controls.VideoDisplayspark.components.VideoPlayermx.controls.VRulespark.primitives.Linemx.controls.VScrollBarspark.components.VScrollBarmx.controls.VSliderspark.components.VSlidermx.core.Applicationspark.components.Applicationmx.core.Windowspark.components.Windowmx.core.WindowedApplicationspark.components.WindowedApplicationmx.containers.Canvasspark.components.Groupmx.containers.HBoxspark.components.HGroupmx.containers.Panelspark.components.Panelmx.containers.Tilespark.components.Group（带一个 TileLayout）mx.containers.VBoxspark.components.VGroup
Adobe 鼓励您与 Spark 组件一起使用 Halo 组件和容器。由于 Adobe 在同一基类 (UIComponent) 上构建组件，Spark 与 Halo 之间应当可以实现全面的可互操作性。下表列出了目前没有 Spark 直接等效类的组件和容器。
Flex 3 类，没有直接的 Flex 4 beta 对应类mx.controls.Alertmx.controls.ColorPickermx.controls.DataGridmx.controls.DateChoosermx.controls.DateFieldmx.controls.Menumx.controls.MenuBarmx.controls.PopUpButtonmx.controls.PopUpMenuButtonmx.controls.ProgressBarmx.controls.RichTextEditormx.controls.TabBarmx.controls.Treemx.containers.Accordionmx.containers.ApplicationControlBarmx.containers.ControlBarmx.containers.DividedBoxmx.containers.Formmx.containers.Gridmx.containers.TabNavigatormx.containers.TitleWindowmx.containers.ViewStack
