Actionscript:
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// toggle a DisplayObject's visible property
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var shape = new Shape();
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shape.visible = !shape.visible;
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trace(shape.visible); // outputs false
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shape.visible = !shape.visible;
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trace(shape.visible); // outputs true
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shape.visible = !shape.visible;
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trace(shape.visible); // outputs false
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shape.visible = !shape.visible;
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trace(shape.visible); // outputs true
This is pretty obvious to anyone with a full understanding of the ! operator. It's useful for things
like checkboxes and other types of toggle buttons. The first time I ever encountered this technique
was in processing source... in one of the demos on toxi.co.uk
Here's another quick example you can run in your timeline:
Actionscript:
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var circle:Shape = new Shape();
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circle.graphics.beginFill(0xFF0000);
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circle.graphics.drawCircle(0, 0,10);
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circle.x = 80;
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circle.y = 105;
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addChild(circle)
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var btn:TextField = new TextField();
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btn.text = "click this text to toggle red circle's visibility";
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btn.x = btn.y = 100;
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btn.selectable = false;
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btn.border = true;
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btn.autoSize = TextFieldAutoSize.LEFT;
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addChild(btn);
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btn.addEventListener(MouseEvent.CLICK, onClick);
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function onClick(evt:MouseEvent):void{
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circle.visible = !circle.visible;
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}
Because "not false" is true.