counting number of rotations of matrix

Question

is there any way to count the number of rotations of a matrix ? i've tried to count the number of times the angle reaches a specific angle (say 60 degree) but it wasn't accurate and it didn't count all the times

i've tried also to take a copy of the matrix by newMatrix.set(originalMatrix) and count number of times that originalMatrix.equals(newMatrix) but wasn't accurate either and also was kinda buggy

my rotate function

void rotate(int x, int y) {

        this.matrix.postRotate((float) (this.startAngle - this.currentAngle),
                x, y);
    }

my onTouch event

case MotionEvent.ACTION_MOVE:

            ring_gear.setCurrentAngle((float) ring_gear.getAngle(
                    event.getX(), event.getY()));
            ring_gear.rotate(ring_gear.Width / 2, ring_gear.Height / 2);

            ring.setImageMatrix(ring_gear.matrix);

            ring_gear.startAngle = ring_gear.currentAngle;