在JPanel中，如何将.png格式的图片设置为背景？

yourJPanel.setBackgroundDecorator(new AssetBakcground(yourImage));

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package{import flash.display.DisplayObject;import flash.display.Sprite;import flash.events.Event;import flash.events.MouseEvent;import flash.filters.DropShadowFilter;import flash.geom.Rectangle;import org.aswing.*;import org.aswing.border.EmptyBorder;public class PanelBg extends Sprite{[Embed(source="icon5.png")]private var imgClass:Class;private var window:JWindow;public function PanelBg(){super();AsWingManager.initAsStandard(this);window = new JWindow();var img:DisplayObject = new imgClass() as DisplayObject;img.filters = [new DropShadowFilter()];//make some blank space leave to the img shadowwindow.setBorder(new EmptyBorder(null, new Insets(0, 0, 4, 4)));window.setBackgroundDecorator(new AssetBackground(img));//or even you can directly call addChild to append a image//window.addChild(img);var buttonPane:JPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));buttonPane.appendAll(new JButton("OK"), new JButton("Cancel"));window.getContentPane().append(buttonPane, BorderLayout.SOUTH);window.getContentPane().append(new JLabel("This is a JWindow"), BorderLayout.CENTER);window.setSizeWH(300, 300);window.show();//simplly make the window dragablewindow.addEventListener(MouseEvent.MOUSE_DOWN, __mouseDown);window.addEventListener(MouseEvent.MOUSE_UP, __mouseUp);}private function __mouseDown(e:Event):void{window.startDrag(false, new Rectangle(0, 0, stage.stageWidth, stage.stageHeight));}private function __mouseUp(e:Event):void{window.stopDrag();}}}

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