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POActionscript Adding Custom Class To .fla
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copied!<p>i'm missing something fundamental here. i have a very simple custom class that draws a circle and a checkbox, and only allows dragging of that circle sprite if the checkbox is checked. a checkbox component is manually added to the library in my .fla.</p> <p>from my .fla project's actions panel:</p> <pre><code>var ball:DragBall = new DragBall(); addChild(ball); </code></pre> <p>my custom class .as file (located in the same folder as the .swf)</p> <pre><code>package { import fl.controls.CheckBox; import flash.display.Sprite; import flash.events.MouseEvent; public class DragBall extends Sprite { private var ball:Sprite; private var checkBox:CheckBox; public function DragBall():void { drawTheBall(); makeCheckBox(); assignEventHandlers(); } private function drawTheBall():void { ball = new Sprite(); ball.graphics.lineStyle(); ball.graphics.beginFill(0xB9D5FF); ball.graphics.drawCircle(0, 0, 60); ball.graphics.endFill(); ball.x = stage.stageWidth / 2 - ball.width / 2; ball.y = stage.stageHeight / 2 - ball.height / 2; ball.buttonMode = true; addChild(ball); } private function makeCheckBox():void { checkBox = new CheckBox(); checkBox.x = 10; checkBox.y = stage.stageHeight - 30; checkBox.label = "Allow Drag"; checkBox.selected = false; addChild(checkBox); } private function assignEventHandlers():void { ball.addEventListener(MouseEvent.MOUSE_DOWN, dragSprite); ball.addEventListener(MouseEvent.MOUSE_UP, dropSprite); } private function dragSprite(evt:MouseEvent):void { if (checkBox.selected) {ball.startDrag();} } private function dropSprite(evt:MouseEvent):void { if (checkBox.selected) {ball.stopDrag();} } } } </code></pre> <p>compiling from the .fla results in the following error, which i don't understand</p> <pre><code> TypeError: Error #1009: Cannot access a property or method of a null object reference. at DragBall/drawTheBall() at DragBall() at DragBall_fla::MainTimeline/frame1() </code></pre>

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