Creating a custom ui element and making it respond to user input

Question

I have a volume knob and would like to know how to make it respond to user input in android. Please point me in the right direction as i have no idea how i can go about it ? Custom Knob looks like something created in this article. My question is what would be the general approach to port this knob into an android application. Do i have to extend the view class and draw this as a Bitmap. If so how exactly would i respond to user input. If this is not possible and i am on the wrong track could someone please tell me how to achieve this?

Answer 1

I would extend the View class.

View is the baseclass for widgets in android (by widgets I mean textfields, buttons, etc), so I think a volue knob would fit right in among those. About the user input, I'm not so sure. I think it depends on how you want to control the knob. I think looking at the onTouchEvent(MotionEvent) would be a good start. My guess is that you will need to overload a similar method anyways.

Related links:

• http://developer.android.com/reference/android/view/View.html
• http://www.vogella.com/articles/AndroidGestures/article.html