Flex - 淡入淡出效果

简介

淡入淡出效果会对组件的 alpha 属性进行动画处理。如果在一个可见属性为 false 的对象上播放，并将其设置为从零到非零值进行 alpha 动画，则它会将对象的可见属性设置为 true，作为淡入的副作用。

类声明

以下是 **spark.effects.Fade** 类的声明：

public class Fade
   extends Animate

公共属性

公共方法

继承的方法

此类继承自以下类：

• spark.effects.Animate
• mx.effects.Effect
• flash.events.EventDispatcher
• Object

Flex 淡入淡出效果示例

让我们按照以下步骤，通过创建一个测试应用程序来检查在 Flex 应用程序中使用淡入淡出效果：

以下是修改后的 mxml 文件 src/com.tutorialspoint/HelloWorld.mxml 的内容。

<?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
   width = "100%" height = "100%" minWidth = "500" minHeight = "500">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         protected function btnFadeIn_clickHandler
            (event:MouseEvent):void {
            fadeIn.play();
         }
         protected function btnFadeOut_clickHandler
            (event:MouseEvent):void {
            fadeOut.play();
         }
      ]]>
   </fx:Script>
   
   <fx:Declarations>
      <s:Fade id = "fadeIn" duration = "2000" target = "{imageFlex}" 
         alphaFrom = "0" alphaTo = "1" />
      <s:Fade id = "fadeOut" duration = "2000" target = "{imageFlex}" 
         alphaFrom = "1" alphaTo = "0" />		   
   </fx:Declarations>
   
   <s:BorderContainer width = "630" height = "480" id = "mainContainer" 
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" 
         horizontalAlign = "center" verticalAlign = "middle">
         <s:Label id = "lblHeader" text = "Effects Demonstration" 
            fontSize = "40" color = "0x777777" styleName = "heading" />
         
         <s:Panel id = "fadePanel" title = "Using Fade Effect" 
            width = "500" height = "300" includeInLayout = "true" visible = "true">
            <s:layout>
               <s:VerticalLayout  gap = "10" verticalAlign = "middle" 
                  horizontalAlign = "center" />
            </s:layout>			
            
            <s:Image id = "imageFlex" 
               source = "https://tutorialspoint.com/images/flex-mini.png" />
            
            <s:HGroup>						
               <s:Button id = "btnFadeOut" label = "Fade Out" 
                  click = "btnFadeOut_clickHandler(event)" />
               <s:Button id = "btnFadeIn" label = "Fade In" 
                  click = "btnFadeIn_clickHandler(event)" />
            </s:HGroup>
          </s:Panel>
       </s:VGroup>	 
    </s:BorderContainer>	
</s:Application>

完成所有更改后，让我们像在 Flex - 创建应用程序 章节中所做的那样，以普通模式编译并运行应用程序。如果应用程序一切正常，它将产生以下结果：[ 在线尝试 ]