adobe flex button change style by actionscript

I have a button to which I have applied stylesheet(belo开发者_开发知识库w) which works great.

.toolButton { up-skin :Embed(source='resources/angle.png'); over-skin :Embed(source='resources/angleH.png'); down-skin :Embed(source='resources/angle.png'); }

Now, I have a new requirement where I need to keep the button in pressed(down) state until the user clicks on this button again. What is the best way I can achieve this.

thank you

---

Use ToggleButton. There is an example at Flex Examples.

For Flex 3 I suppose a ToggleButtonBar with a single button in it would do.