Flex 4：状态改变事件

Question

在Flex 4中，有没有我可以使用的事件来检测状态变化？

- ChrisInCambo

Answer 1

我知道这个问题很老，但是通过谷歌搜索状态变化事件，我仍然到达了这里，所以对于想要知道的人：

有一个由组件分派的StateChangeEvent.CURRENT_STATE_CHANGE事件，因此您的应用程序也可以侦听该事件。

在您的侦听器函数中，您可以访问StateChangeEvent.oldState和StateChangeEvent.newState属性。

- Siebe

Answer 2

如果你想要讨论视图状态，那么答案是肯定的。你可以像这样监听enterState事件（对于示例的简单性我表示抱歉，它是我正在处理的项目的一部分，并且我删除了任何相关代码）：

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
           xmlns:s="library://ns.adobe.com/flex/spark" 
           xmlns:mx="library://ns.adobe.com/flex/mx"
           minWidth="800" minHeight="600"
           currentState="loading">

<fx:Script>
    <![CDATA[
        import mx.controls.Alert;

        private function onEnterLoadingState():void{
            Alert.show("Enter the loading state.", "Application");
        }

        private function onEnterLoginState():void{
            Alert.show("Enter the login state.", "Application");
        }

        private function onEnterAddState():void{
            Alert.show("Enter the addUser state.", "Application");
        }

        private function changeState(state:String):void{
            currentState = state;
        }
    ]]>
</fx:Script>

<s:states>
    <s:State name="loading" enterState="onEnterLoadingState()"/>
    <s:State name="login" enterState="onEnterLoginState()"/>
    <s:State name="addUser" enterState="onEnterAddState()"/>
</s:states>

<s:Panel id="loadView" includeIn="loading" title="Loading">
    <s:Button label="Go to login" click="changeState('login')"/>
</s:Panel>
<s:Panel id="loginView" includeIn="login" title="Login">
    <s:Button label="Go to addUser" click="changeState('addUser')"/>
</s:Panel>
<s:Panel id="addView" includeIn="addUser" title="AddUser">
    <s:Button label="Return to loading" click="changeState('loading')"/>
</s:Panel>
</s:Application>

如果需要，还有一个exitState事件。希望这对你有所帮助。

- Diego

Answer 3

在任何UIComponent类上，您可以监听多个状态事件：

• FlexEvent.STATE_CHANGE_COMPLETE
• FlexEvent.STATE_CHANGE_INTERRUPTED
• StateChangeEvent.CURRENT_STATE_CHANGING
• StateChangeEvent.CURRENT_STATE_CHANGE
• FlexEvent.ENTER_STATE
• FlexEvent.EXIT_STATE

MXML：

<?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"

                       enterState="windowedapplication1_enterStateHandler(event)"
                       exitState="windowedapplication1_exitStateHandler(event)"
                       currentStateChange="windowedapplication1_currentStateChangeHandler(event)"
                       currentStateChanging="windowedapplication1_currentStateChangingHandler(event)"
                       stateChangeInterrupted="windowedapplication1_stateChangeInterruptedHandler(event)"
                       stateChangeComplete="windowedapplication1_stateChangeCompleteHandler(event)">

    <fx:Script>
        <![CDATA[
            import mx.events.FlexEvent;


            protected function windowedapplication1_stateChangeCompleteHandler(event:FlexEvent):void
            {

            }

            protected function windowedapplication1_stateChangeInterruptedHandler(event:FlexEvent):void
            {

            }

            protected function windowedapplication1_currentStateChangeHandler(event:StateChangeEvent):void
            {
                var oldState:String = event.oldState;
                var newState:String = event.newState;
            }

            protected function windowedapplication1_currentStateChangingHandler(event:StateChangeEvent):void
            {
                var oldState:String = event.oldState;
                var newState:String = event.newState;
            }

            protected function windowedapplication1_enterStateHandler(event:FlexEvent):void
            {

            }

            protected function windowedapplication1_exitStateHandler(event:FlexEvent):void
            {

            }
        ]]>
    </fx:Script>
</s:WindowedApplication>

- 1.21 gigawatts