我在列表中使用了自定义 IconItemRender。当我将图像嵌入列表并在设备上进行测试时,列表滚动的动画并不酷,它是滞后的。如果不嵌入图像列表滚动的动画是好的。
任何建议为什么列出滞后?
这是代码:
package components
{
import flash.display.Bitmap;
import flash.display.DisplayObject;
import flash.display.Sprite;
import flash.text.Font;
import flash.text.TextField;
import flash.text.TextFormat;
import mx.core.DPIClassification;
import spark.components.IconItemRenderer;
import spark.components.Image;
import spark.components.LabelItemRenderer;
import spark.components.supportClasses.StyleableTextField;
public class Shops extends IconItemRenderer
{
private static var bkgColor:Boolean;
protected var storeName:StyleableTextField;
protected var floor:StyleableTextField;
protected var _data:Object;
protected var floorTextSize:int;
protected var promotions:Image;
protected var promotionHolder:Sprite;
[Embed(source="assets/map_list320.png")]
public static const mapList:Class;
public function Shops()
{
//TODO: implement function
super();
switch (applicationDPI) {
case DPIClassification.DPI_160:
floorTextSize = 11;
break;
case DPIClassification.DPI_240:
floorTextSize = 20;
break;
case DPIClassification.DPI_320:
floorTextSize = 16;
break;
}
}
/**
* @private
*
* Override this setter to respond to data changes
*/
override public function set data(value:Object):void
{
_data = value;
if (storeName) storeName.text = _data.title;
if (floor) floor.text = 'етаж: ' + _data.floor;
// the data has changed. push these changes down in to the
// subcomponents here
}
/**
* @private
*
* Override this method to create children for your item renderer
*/
override protected function createChildren():void
{
// promotion if exist
promotionHolder = new Sprite();
addChild(promotionHolder);
// store name
storeName = new StyleableTextField();
storeName.defaultTextFormat = new TextFormat( getStyle( "fontFamily" ), getStyle( "fontSize" ), getStyle('color') );
addChild( storeName );
// floor
floor = new StyleableTextField();
floor.defaultTextFormat = new TextFormat(getStyle( "fontFamily" ), floorTextSize, 0x999999);
addChild(floor);
// map
var img:Image = new Image();
img.source = mapList;
img.cacheAsBitmap = true;
img.width = 64;
img.height = 64;
addChild(img);
}
/**
* @private
*
* Override this method to change how the item renderer
* sizes itself. For performance reasons, do not call
* super.measure() unless you need to.
*/
override protected function measure():void
{
}
/**
* @private
*
* Override this method to change how the background is drawn for
* item renderer. For performance reasons, do not call
* super.drawBackground() if you do not need to.
*/
override protected function drawBackground(unscaledWidth:Number, unscaledHeight:Number):void
{
graphics.beginFill(bkgColor ? 0xFFFFFF : 0xf0f4fb, 1);
graphics.drawRect(0, 0, unscaledWidth, unscaledHeight);
bkgColor = !bkgColor;
}
/**
* @private
*
* Override this method to change how the background is drawn for this
* item renderer. For performance reasons, do not call
* super.layoutContents() if you do not need to.
*/
override protected function layoutContents(unscaledWidth:Number,
unscaledHeight:Number):void
{
super.layoutContents(unscaledWidth, unscaledHeight);
// layout all the subcomponents here
}
override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
{
// position the field
storeName.x = unscaledWidth / 10;
storeName.y = (unscaledHeight - (storeName.textHeight + floor.textHeight + (unscaledHeight/10))) / 2;
floor.x = unscaledWidth / 10;
floor.y = storeName.y + storeName.textHeight + (unscaledHeight/10);
// we draw a separator line between each item
var lineY:int = unscaledHeight -1;
graphics.clear();
graphics.lineStyle(1, 0xd9d9d9);
graphics.moveTo( 0, lineY );
graphics.lineTo( unscaledWidth, lineY );
drawBackground(unscaledWidth, unscaledHeight);
}
}
}