Start by creating your own View.OnTouchListener. This will calculate and determine whether the click should be actioned or not.

  public class AreaVeto implements View.OnTouchListener {
    public boolean onTouch(View v, MotionEvent event) {
       // Calculation here. 

      return ... // Use false if click is within area?
    }
  }

For calculating whether the click is within the area, the MotionEvent parameters have getX() and getY() to tell you where the click has occured. Because a calculation is being performed, dealing with buttons of any random shape would be more complex. If you are using an image with trasparent background, perhaps you can try calling Bitmap.getPixel() to get the colour at the location to decide whether it is within the clickable area. Obviously, this also implies that the listener needs to know about the bitmap.

After creating your listener, you need to set it as the touch listener. This is done by calling the View.setOnTouchListener() method. You can call this method from within the customised view class or after your view is created.

Hopefully, this will give you a clearer idea of what I was thinking of.

Secondly, I assume you are asking how to change the text. The custom view actually takes in the text label for the button as an argument to its constructor. If you are talking about the positioning of the text, look at onDraw(). Documentation states:

Method called on to render the view.

It is also here that I draw the text with the call to canvas.drawText().

Thanks in advance for your help

kahgoh
10 June, 2009 at 8:45 pm

I’ve never tried this myself, but I would probably start by looking at overriding onTouchEvent(). It receives a MotionEvent object that has information about the X and Y co-ordinates, so from there I believe you should be able to control whether the event gets processed or not.

Could you please tell me where and what code should be inserted to extend the button to fit the text?