Surface view for creating animated arcs

CirclesActivity.java

package com.freefallhighscore.circles;


import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.AnimationUtils;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class CirclesActivity extends Activity {
    /** Called when the activity is first created. */
	
	private Handler mHandler = new Handler();
	TextView tv;
	DrawCanvas canvasView;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        RelativeLayout wheel = (RelativeLayout) findViewById(R.id.wheel);
        canvasView = new DrawCanvas(this);
         
         wheel.addView(canvasView);
       
    }
    
    @Override
    protected void onResume() {
     // TODO Auto-generated method stub
     super.onResume();
     canvasView.onResumeMySurfaceView();
    }
    
    @Override
    protected void onPause() {
     // TODO Auto-generated method stub
     super.onPause();
     canvasView.onPauseMySurfaceView();
    }
     
	private Runnable mUpdateTimeTask = new Runnable() {
		long start = SystemClock.uptimeMillis();
		public void run() {
			long millis = SystemClock.uptimeMillis() - start;
			canvasView.slice = millis/20000.0;
			//tv.setText(String.valueOf(canvasView.slice));
			if(millis<20000) mHandler.postAtTime(this, start + millis);
			else{
				mHandler.removeCallbacks(mUpdateTimeTask);
			}
		}
	};

	public void go(View view){
		mHandler.removeCallbacks(mUpdateTimeTask);  //Remove old timer
	    mHandler.postDelayed(mUpdateTimeTask, 100);	
	
	}
    

}

DrawCanvas.java

package com.freefallhighscore.circles;

import java.util.Random;

import android.R.color;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;

class DrawCanvas extends SurfaceView implements Runnable{
    
    Thread thread = null;
    SurfaceHolder surfaceHolder;
    volatile boolean running = false;
    public double slice;
     
  public DrawCanvas(Context context) {
   super(context);
   // TODO Auto-generated constructor stub
   surfaceHolder = getHolder();
   
  }
   
  public void onResumeMySurfaceView(){
   running = true;
   thread = new Thread(this);
   thread.start();
  }
   
  public void onPauseMySurfaceView(){
   boolean retry = true;
   running = false;
   while(retry){
    try {
     thread.join();
     retry = false;
    } catch (InterruptedException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
  }
 
  
  public void run() {
   // TODO Auto-generated method stub
   while(running){
    if(surfaceHolder.getSurface().isValid()){
    	surfaceHolder.setFormat(PixelFormat.TRANSPARENT);
     Canvas canvas = surfaceHolder.lockCanvas();
     
     Paint mPaints = new Paint();
     mPaints.setAntiAlias(true);
     //mPaints.setStyle(Paint.Style.FILL);
     mPaints.setColor(0x8800FF00);
     RectF bounds= new RectF( 0, 0, 100, 100);
     
     canvas.drawArc(bounds, -90, (float) (slice*360), true, mPaints);
      
     surfaceHolder.unlockCanvasAndPost(canvas);
    }
   }
  }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#bbbbbb"
    
   
    >
  
    <RelativeLayout
	    android:id="@+id/wheel"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:layout_marginLeft="20dip"
	    android:layout_marginBottom="20dip"
	    android:layout_alignParentBottom="true"
	    />
	
	    <Button
    android:id="@+id/btn"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:text="Touch Me"
	    android:onClick="go"
    />  


</RelativeLayout>