一个简单的组件弹出弹入效果

什么是好的效果。我的体会是那些模拟真实世界的物体运动，被现有物理学所支持的简洁效果才是历久常新，实用的好效果。这是由人脑本身的思维模式所决定的。iPhone就是一个很典型的例子。某些视觉冲击极强的效果，在初接触的时候确实能给人耳目一新的感觉，但是超现实的手法看久了难免会有审美疲劳，反而会让人觉得是形式大于内容。这和吃多了大鱼大肉会腻味是一个道理。

OK, 废话到此为止。Flex 本身的 PopupButton 实现了一种弹出弹入组件的效果。我很喜欢。遗憾的是A司并没有把这种效果抽取出来作为效果类发布。好在原理和实现都不复杂，所以自己写了一个，功能并不完善但刚刚够用。合适的才是最好的嘛。



原理很简单：利用继承 Animate 效果类， 操作 UIComponent 的 scrollRect 的 x|y 坐标值来实现目标组件弹出和弹入。考虑到有些组件有用样式产生的阴影，这种阴影显示在 scrollRect 的范围之外，所以效果使用了边际值来补偿这种显示局限。用代码说话。

PopupEffect.mxml

<?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"
					xmlns:myEffect="customEffect.*"
					width="600" height="600" viewSourceURL="srcview/index.html">
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Declarations>
		<s:Power id="powerEasing" exponent="5"/>
		<!--
		主要属性说明：
			direction  up, down, left, right —— 控制组件的运动方向
			marginTop
			marginBottom
			marginLeft
			marginRight —— 整形，表像素， 控制组件的边际空白大小
		-->
		<myEffect:PopupEffect id="popup" direction="left" easer="{powerEasing}" duration="500"
									 marginLeft="20" marginRight="20" marginBottom="20" />
	</fx:Declarations>
	
	<s:states>
		<s:State name="Un" />
		<s:State name="Deux" />
		<s:State name="Trois" />
	</s:states>
	
	<s:transitions>
		<s:Transition>
			<myEffect:PopupEffect targets="{[p1,i2,r3]}"
										 direction="up" duration="500" marginLeft="20" marginRight="20" marginBottom="20" />
		</s:Transition>
	</s:transitions>
	
	<!-- View State 演示 -->
	<s:Panel id="p1" width="390" height="200" title="Un" includeIn="Un" x="110" y="50">
		<s:Label text="This is a Panel with dropShadow"  x="56" y="60" fontSize="19"/>
	</s:Panel>
	<mx:Image id="i2" source="@Embed(source='assets/logo.jpg')" horizontalCenter="0" verticalCenter="-178" includeIn="Deux"/>
	<mx:RichTextEditor id="r3" height="200" width="390" text="View State Trois" horizontalCenter="0" verticalCenter="-160" includeIn="Trois"/>
	<s:Button label="Un" width="40" x="75" y="94" rotation="-90" click="currentState='Un'" />
	<s:Button label="Deux" width="50" x="75" y="150" rotation="-90" click="currentState='Deux'" />
	<s:Button label="Trois" width="60" x="75" y="217" rotation="-90" click="currentState='Trois'" />
	
	<!-- ViewStack 演示 -->
	<mx:ViewStack id="viewstack1" horizontalCenter="-2" verticalCenter="119" height="220" width="446">
		<s:NavigatorContent label="Alpha" width="100%" height="100%" showEffect="{popup}" hideEffect="{popup}">
			<s:Panel width="390" height="200" title="View Alpha" horizontalCenter="0" verticalCenter="0">
				<s:Label text="This is a Panel with dropShadow"  x="56" y="60" fontSize="19"/>
			</s:Panel>
		</s:NavigatorContent>
		<s:NavigatorContent label="Bravo" width="100%" height="100%" showEffect="{popup}" hideEffect="{popup}">
			<mx:Image source="@Embed(source='assets/logo.jpg')" horizontalCenter="0" verticalCenter="0"/>
			<s:Label y="182" text="View Bravo" fontSize="16" horizontalCenter="0"/>
		</s:NavigatorContent>
		<s:NavigatorContent label="Charlie" width="100%" height="100%" showEffect="{popup}" hideEffect="{popup}">
			<mx:RichTextEditor  height="200" width="390" text="View Charlie" horizontalCenter="0" verticalCenter="0"/>
		</s:NavigatorContent>
	</mx:ViewStack>
	<s:ButtonBar dataProvider="{viewstack1}" x="197" y="543"/>
	<s:Label x="243" y="291" text="ViewStack 示例" fontSize="17" x.Un="243" y.Un="297" text.Un="ViewStack 演示"/>
	<s:Label includeIn="Un" x="238" y="27" text="View State 演示" fontSize="16"/>
	
</s:Application>

PopupEffect.as

/* Copyright 2010 Tu Ding */

package customEffect{
import flash.geom.Rectangle;

import mx.core.IVisualElement;
import mx.core.IVisualElementContainer;
import mx.core.UIComponent;
import mx.effects.IEffectInstance;
import mx.events.FlexEvent;

import spark.effects.Animate;
import spark.effects.animation.Animation;
import spark.effects.animation.IAnimationTarget;
import spark.effects.animation.MotionPath;
import spark.effects.animation.SimpleMotionPath;
import spark.effects.supportClasses.AnimateInstance;

/* 实现组件的弹入或弹出效果  */
public class PopupEffect extends Animate {
	
	/* 组件运动的方向 “上右下左” */
	[Inspectable( catalog="Common", type="String",enumeration="up,right,down,left", defaultValue = "up" )]
	public var direction:String = "up";
	
	// 考虑到有些组件的阴影或滤镜效果，需要设置一个对目标组件的边际填充值
	[Inspectable( catalog="General", type="Number", defaultValue = "0" )]
	public var marginTop:int = 0;
	[Inspectable( catalog="General", type="Number", defaultValue = "0" )]
	public var marginRight:int = 0;
	[Inspectable( catalog="General", type="Number", defaultValue = "0" )]
	public var marginBottom:int = 0;
	[Inspectable( catalog="General", type="Number", defaultValue = "0" )]
	public var marginLeft:int = 0;
	
	public function PopupEffect( target:UIComponent = null )
	{
		super( target );
		instanceClass = PopupEffectInstance;
	}
	

	override protected function initInstance(instance:IEffectInstance):void
	{
		super.initInstance( instance );
		var inst:PopupEffectInstance = instance as PopupEffectInstance;
		inst.direction = direction;
		inst.marginTop = marginTop;
		inst.marginRight = marginRight;
		inst.marginBottom = marginBottom;
		inst.marginLeft = marginLeft;
	}
	
	/**
	 *  @private
	 */
	override public function getAffectedProperties():Array /* of String */
	{
		return ["parent"];
	}

}
}


import flash.geom.Rectangle;

import mx.core.UIComponent;
import mx.events.FlexEvent;

import spark.effects.animation.Animation;
import spark.effects.animation.MotionPath;
import spark.effects.animation.SimpleMotionPath;
import spark.effects.supportClasses.AnimateInstance;

class PopupEffectInstance extends AnimateInstance {
	
	public var direction:String;
	public var marginTop:int;
	public var marginRight:int;
	public var marginBottom:int;
	public var marginLeft:int;
	
	public function PopupEffectInstance( target:Object )
	{
		super( target );
		autoRemoveTarget = true;
	}
	
	
	override public function play():void
	{
		var t:UIComponent = target as UIComponent;
		var scrollX:int = 0;
		var scrollY:int = 0;
		// 效果实际是利用 UIComponent 的 scrollRect 来实现，结合组件的边际填充来设置 scrollRect 的尺寸
		var rectWidth:int = t.width + marginLeft + marginRight;
		var rectHeight:int = t.height + marginTop + marginBottom;
		
		// 保存效果中组件需要的位移
		var offset:int;
		// 由于  marginLeft 的存在，需要修正坐标值组件 scrollRect 的初始坐标
		var revisedLocation:int;
		
		// 修改组件位置以补偿设置 scrollRect 后造成的偏移
		// 修改只需要在第一次应用效果时，通过条件判断避免多次修改
		if ( null == t.scrollRect )
		{
			t.x -= marginLeft;
			t.y -= marginTop;
		}
		
		switch( direction )
		{
			case "up":
				revisedLocation = -marginTop; 
				offset = rectHeight;
				scrollY = offset;
				break;
			case "right":
				revisedLocation = -marginLeft;
				offset = -rectWidth;
				scrollX = offset;
				break;
			case "down":
				revisedLocation = -marginTop;
				offset = -rectHeight;
				scrollY = offset;
				break;
			case "left":
				revisedLocation = -marginLeft;
				offset = rectWidth;
				scrollX = offset;
		}
		
		if ( null != triggerEvent )
			if ( triggerEvent.type == FlexEvent.SHOW )
			{
				t.scrollRect = new Rectangle( scrollX - marginLeft, scrollY - marginTop, rectWidth, rectHeight );
				motionPaths = new <MotionPath>[ new SimpleMotionPath("value", offset, revisedLocation)];
			}else{
				t.scrollRect = new Rectangle( 0 - marginLeft, 0 - marginTop, rectWidth, rectHeight );
				motionPaths = new <MotionPath>[ new SimpleMotionPath("value", revisedLocation, offset)];
			}
		
		if ( propertyChanges )
		{
			var parentChange:Boolean = 
				propertyChanges.end["parent"] !== undefined &&
				propertyChanges.end["parent"] != propertyChanges.start["parent"];
			if ( parentChange )
			{
				var moveIn:Boolean = parentChange && propertyChanges.end["parent"];
				if (moveIn)
				{
					t.scrollRect = new Rectangle( scrollX - marginLeft, scrollY - marginTop, rectWidth, rectHeight );
					motionPaths = new <MotionPath>[ new SimpleMotionPath("value", offset, revisedLocation)];
				}
				else
				{
					t.scrollRect = new Rectangle( 0 - marginLeft, 0 - marginTop, rectWidth, rectHeight );
					motionPaths = new <MotionPath>[ new SimpleMotionPath("value", revisedLocation, offset)];
				}
			}
		}
		
		super.play();
	}
	
	
	override public function animationUpdate(animation:Animation):void
	{
		super.animationUpdate(animation);
		
		var t:UIComponent = target as UIComponent;
		var rect:Rectangle = t.scrollRect;
		if ( direction == "up" || direction == "down" )
			rect.y = int(animation.currentValue["value"]);
		else
			rect.x = int(animation.currentValue["value"]);
		t.scrollRect = rect;
	}
	
}

好文章, 现在直接用spark Animate的例子还真不多呀!!

文件还可以，我正想学习来的