Flex：更新标签的文本，这是一个变量 [英] Flex: Update a label's text, which is a variable

问题描述

我有一个标签，当你点击一个按钮时，它会从var中获取它的值。 var已被声明：

  public function clickevent 
 {
 label.text = aVariable; 
 
 
 
 
 
 $ b现在我知道如果我有这样的标签：
 < s：Label id =label2text ={aVariable}/> 
  
和aVariable是空的，label2的文本是Null（它不会给出错误，只是Null 在我的情况）。这是我目前的情况。 
 
 
 
我想知道的是当我稍后将aVariable的值更改为字符串hasChanged时，例如。标签2的文本也应该改变为hasChanged，而用户不必按下按钮或任何东西来进行这种改变。如何做到这一点？
 
解决方案
我不是100％确定我理解你的问题，但如果你的变量被声明为可绑定，无论你的脚本改变了它的值还是一个按钮，标签的文本属性都会随着绑定而变化。 
 
 
 <？xml version =1.0encoding =utf-8？> 
  xmlns：s =library：//ns.adobe.com/flex/spark 
 xmlns：mx =library：//ns.adobe.com/flex/mx> 
 
< fx：Script> 
<！[CDATA [
 [Bindable] 
 private var aVariable：String; 
 
 protected function button1_clickHandler（event：MouseEvent）：void 
 {
 aVariable =My new value; 
} 
]]> 
< / fx：Script> 
 
< s：layout> 
< s：VerticalLayout /> 
< / s：layout> 
 
  
  
< / s：WindowedApplication> 
  
 
I have a label that get it's value from a var when you click on a button. The var has already been declared: 
public function clickevent
{
label.text = aVariable; 
}
Now I know that if i have a label like this: 
<s:Label id="label2" text="{aVariable}"/> 
and aVariable is empty, label2's text is Null (it doesn't give an error, just "Null" in my situation). This is my current situation. 

What I'd like to know is when I later on change the aVariable's value to a string "hasChanged", for example. The label2's text should also change to "hasChanged" without the user having to push a button or anything to make this change. How can this be done?
解决方案
I'm not 100% sure I understand your question but if your variable is declared as "bindable", no matter if your script change its value or a button, your text propertie of the label will follow as it is binded.
<?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[
            [Bindable]
            private var aVariable:String;

            protected function button1_clickHandler(event:MouseEvent):void
            {
                aVariable = "My new value";
            }
        ]]>
    </fx:Script>

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

    <s:Label text="{aVariable}"/>

    <s:Button label="Click me" click="button1_clickHandler(event)"/>

</s:WindowedApplication>


                        
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