Flex 4 - Create states and add elements at runtime

问题:

I wanna add dynamically (at runtime) new states to a container and, to this states, add different elements (like TextInput, Label etc.). This must be done from actionscript, I don't use any mxml file. I can add states and change properties or styles for different elements, but I didn't figured out how to add child elements for different states.

回答1:

You'll have to manually create an instance of the State class and create overrides for it. Then add the newly created state to the states array of your component.

Here's a small example air application that shows how to do it:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
                       xmlns:s="library://ns.adobe.com/flex/spark" 
                       xmlns:mx="library://ns.adobe.com/flex/mx">
    <fx:Script>
        <![CDATA[
            import mx.events.FlexEvent;
            import mx.states.AddChild;
            import mx.states.AddItems;
            import mx.states.SetProperty;
            import mx.states.State;

            protected function createState(event:MouseEvent):void
            {
                var label:Label = new Label();
                label.text = "World!";

                var addLabel:AddItems = new AddItems();
                addLabel.relativeTo = foo;
                addLabel.position = "after";
                addLabel.items = label;

                var helloWorld:State = new State();
                helloWorld.name = "helloWorld";
                helloWorld.overrides = [addLabel];

                states = [helloWorld];
                currentState = "helloWorld";
            }
        ]]>
    </fx:Script>

    <s:layout>
        <s:VerticalLayout />
    </s:layout>

    <s:Label id="foo" text="Hello" />

    <s:Button label="Create new state" click="createState(event)" />
</s:WindowedApplication>