Android - trouble in implementing this user interface - 2d

Question

I am trying to implement a UI like this one..
http://www.shrenikvikam.com/wp-content/uploads/2011/04/214e422a43E11S3.png-150x134.png
But i am having some trouble implementing this.. Could someone tell me mistakes in this...
public class Meter extends View{
static final int ORBIT_COLOR = Color.argb(255, 66, 66, 66);
static final double RAD_CIRCLE = 2*Math.PI; // Number radians in a circle
private Paint paint; // Paint object controlling format of screen draws
private ShapeDrawable planet; // Planet symbol
private int planetRadius = 7; // Radius of spherical planet (pixels)
private int sunRadius = 12; // Radius of Sun (pixels)
private float X0 = 0; // X offset from center (pixels)
private float Y0 = 0; // Y offset from center (pixels)
private float X; // Current X position of planet (pixels)
private float Y; // Current Y position of planet (pixels)
private float centerX; // X for center of display (pixels)
private float centerY; // Y for center of display (pixels)
private float R0; // Radius of circular orbit (pixels)
private int nsteps = 120; // Number animation steps around circle
private double theta; // Angle around orbit (radians)
private double dTheta; // Angular increment each step (radians)
private double direction = -1; // Direction: counter-clockwise -1; clockwise +1
private float lastTouchX; // x coordinate of symbol i at last touch
private float lastTouchY; // x coordinate of symbol i at last touch
private int divisions = 120; // Since it requires temperature change from 0 -120
private double oneSegmentLength = (2 * Math.PI * R0)/(double)120;
public Meter(Context context) {
super(context);
// Initialize angle and angle step (in radians)
theta = 30;
//dTheta = RAD_CIRCLE/((double) nsteps); // Angle increment in radians
dTheta = ((360-60)/(double)divisions);
planet = new ShapeDrawable(new OvalShape());
planet.getPaint().setColor(Color.WHITE);
planet.setBounds(0, 0, 2*planetRadius, 2*planetRadius);
paint = new Paint();
paint.setAntiAlias(true);
paint.setTextSize(14);
paint.setStrokeWidth(1);
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
int action = ev.getAction();
switch (action) {
// MotionEvent class constant signifying a finger-down event
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
lastTouchX = x;
lastTouchY = y;
newXY();
break;
}
// MotionEvent class constant signifying a finger-drag event
case MotionEvent.ACTION_MOVE: {
float newX = ev.getX();
float newY = ev.getY();
float dx = newX - lastTouchX;
float dy = newY - lastTouchY;
int diff = (int) (Math.abs(ev.getX()) % Math.abs(oneSegmentLength));
if(diff == 0){
if(Math.abs(dx) > Math.abs(dy)) {
if(dx>0) direction = 1;
else direction = -1;
newXY();
} else {
newXY();
}
Log.d("MOVE", "dx ->" + dx + " one seg->" + oneSegmentLength);
invalidate();
}
break;
}
// MotionEvent class constant signifying a finger-up event
case MotionEvent.ACTION_UP: {
Log.d("ACTION MOVE","Value ->");
final float x = ev.getX();
final float y = ev.getY();
lastTouchX = x;
lastTouchY = y;
newXY();
break;
}
}
return true;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
drawBackground(paint, canvas);
canvas.save();
canvas.translate(X + X0, Y + Y0);
planet.draw(canvas);
canvas.restore();
}
// Called by onDraw to draw the background
private void drawBackground(Paint paint, Canvas canvas){
paint.setColor(Color.YELLOW);
paint.setStyle(Paint.Style.FILL);
canvas.drawCircle(centerX + X0, centerY + Y0, sunRadius, paint);
paint.setStyle(Paint.Style.STROKE);
paint.setColor(ORBIT_COLOR);
canvas.drawCircle(centerX + X0, centerY + Y0, R0, paint);
}
//Method to increment angle theta and compute the new X and Y .
private void newXY(){
theta += dTheta;
Log.d("THETA VAL", "->" + theta);
//if(theta > RAD_CIRCLE) theta -= RAD_CIRCLE; // For convenience, keep angle 0-2pi
if(theta > 150)theta = 30;
if(theta > 30 && theta <120){
X = (float)(R0*Math.sin(direction*theta)) + centerX - planetRadius;
Y = centerY - (float)(R0*Math.cos(direction*theta)) - planetRadius;
}
//Log.i("ANIMATOR", "X="+X+" Y="+Y);
}
#Override
protected void onSizeChanged (int w, int h, int oldw, int oldh){
// Coordinates for center of screen
centerX = w/2;
centerY = h/2;
// Make orbital radius a fraction of minimum of width and height of display
R0 = (float) (0.90*Math.min(centerX, centerY));
oneSegmentLength = (2 * Math.PI * R0)/(double)120;
// Set the initial position of the planet (translate by planetRadius so center of planet
// is at this position)
X = centerX - planetRadius ;
Y = centerY - R0 - planetRadius;
}
}
I am referring this code to do this implementation...
http://eagle.phys.utk.edu/guidry/android/animatorDemo.html
I am just drawing a circle and trying to implement the same motion between 0 -120 degrees..