Q:

what this integer value means?

I found this on one of  the android tutorials site.
The whole program illustrates the bouncing ball with custom view.
I could not understand this line.
 private int xVelocity = 30;
    xVelocity = xVelocity*-1;

What this * means?
If i remove this * than the animation in drametically changed.
And another thing that  invalidate() method of view class is same as repaint() of java??? 
Any help Would be appericiated.

A:

Multiplication.
xVelocity*-1

Multiply xVelocity by -1.
xVelocity-1

Subtract 1 from xVelocity.

And another thing that invalidate() method of view class is same as repaint() of java?

Yes, invalidate() marks the view as dirty and therefore schedules a redraw.

