ViewStack作为选择性组件的数据源

    <mx:ButtonBar id="buttonBar"
            dataProvider="{viewStack}"
            buttonHeight="32" />

    <mx:ViewStack id="viewStack">
        <mx:VBox label="Button"
                icon="@Embed('assets/Button.png')"
                backgroundColor="white"
                width="480"
                height="60">
            <mx:Label text="Button..." />
        </mx:VBox>
        <mx:VBox label="ButtonBar"
                icon="@Embed('assets/ButtonBar.png')"
                backgroundColor="white"
                width="480"
                height="60">
            <mx:Label text="ButtonBar..." />
        </mx:VBox>
        <mx:VBox label="CheckBox"
                icon="@Embed('assets/CheckBox.png')"
                backgroundColor="white"
                width="480"
                height="60">
            <mx:Label text="CheckBox..." />
        </mx:VBox>
        <mx:VBox label="ColorPicker"
            icon="@Embed('assets/ColorPicker.png')"
                backgroundColor="white"
                width="480"
                height="60">
            <mx:Label text="ColorPicker..." />
        </mx:VBox>
    </mx:ViewStack>