public class DrawView extends View
{
	private Canvas  	m_Canvas;

	private Path    	m_Path;

	private Paint       m_Paint;

	ArrayList<Pair<Path, Paint>> arrayListPaths = new ArrayList<Pair<Path, Paint>>();

	ArrayList<Pair<Path, Paint>> undonePaths = new ArrayList<Pair<Path, Paint>>();

	private float mX, mY;

	private Bitmap bitmapToCanvas;

	private static final float TOUCH_TOLERANCE = 4;

	public DrawView(Context context)
	{
		super(context);
		setFocusable(true);
		setFocusableInTouchMode(true);

		onCanvasInitialization();
	}

	public void onCanvasInitialization()
	{
		m_Paint = new Paint();
		m_Paint.setAntiAlias(true);
		m_Paint.setDither(true);
		m_Paint.setColor(Color.parseColor("#37A1D1"));
		m_Paint.setStyle(Paint.Style.STROKE);
		m_Paint.setStrokeJoin(Paint.Join.ROUND);
		m_Paint.setStrokeCap(Paint.Cap.ROUND);
		m_Paint.setStrokeWidth(2);

		m_Path = new Path();
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh)
	{
		super.onSizeChanged(w, h, oldw, oldh);

		bitmapToCanvas = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
		m_Canvas = new Canvas(bitmapToCanvas);
	}

	@Override
	protected void onDraw(Canvas canvas)
	{
		canvas.drawBitmap(bitmapToCanvas, 0f, 0f, null);
		canvas.drawPath(m_Path, m_Paint);
	}

	public void onDrawCanvas()
	{
		for (Pair<Path, Paint> p : arrayListPaths)
		{
		    m_Canvas.drawPath(p.first, p.second);
		}
	}

	private static final int INVALID_POINTER_ID = -1;

	// The ‘active pointer’ is the one currently moving our object.
	private int mActivePointerId = INVALID_POINTER_ID;

	@Override
    public boolean onTouchEvent(MotionEvent ev)
	{
   		super.onTouchEvent(ev);

   		final int action = ev.getAction();

   		switch (action & MotionEvent.ACTION_MASK)
		{
    		case MotionEvent.ACTION_DOWN:
    		{
    			break;
    		}
    		case MotionEvent.ACTION_POINTER_DOWN:
    		{
    			final float x = ev.getX();
    	        final float y = ev.getY();

    			touch_start(x, y);

    			mActivePointerId = ev.getPointerId(0);
	    		break;
    		}
    		case MotionEvent.ACTION_MOVE:
    		{
    			// Find the index of the active pointer and fetch its position
    	        final int pointerIndex = ev.findPointerIndex(mActivePointerId);
    	        final float x = ev.getX(pointerIndex);
    	        final float y = ev.getY(pointerIndex);

    	        touch_move(x, y);
	    		break;
    		}
    		case MotionEvent.ACTION_UP:
    		{
    			mActivePointerId = INVALID_POINTER_ID;
    			break;
    		}
    		case MotionEvent.ACTION_CANCEL: {
    	        mActivePointerId = INVALID_POINTER_ID;
    	        break;
    	    }
    		case MotionEvent.ACTION_POINTER_UP:
    		{
    			// Extract the index of the pointer that left the touch sensor
    	        final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
    	                >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
    	        final int pointerId = ev.getPointerId(pointerIndex);
    	        if (pointerId == mActivePointerId)
    	        {
    	            // This was our active pointer going up. Choose a new
    	            // active pointer and adjust accordingly.
    	            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
    	            mX = ev.getX(newPointerIndex);
    	            mY = ev.getY(newPointerIndex);
    	            mActivePointerId = ev.getPointerId(newPointerIndex);
    	        }
    			touch_up();
    		}
    		break;
    		case MotionEvent.ACTION_OUTSIDE:
    		break;
    	}

    	invalidate();
    	return true;
    }

	private void touch_start(float x, float y)
	{
		undonePaths.clear();
		m_Path.reset();
		m_Path.moveTo(x, y);
		mX = x;
		mY = y;
	}

	private void touch_move(float x, float y)
	{
		float dx = Math.abs(x - mX);
		float dy = Math.abs(y - mY);
		if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE)
		{
			m_Path.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
			mX = x;
			mY = y;
		}
	}
	private void touch_up()
	{
		m_Path.lineTo(mX, mY);

		// commit the path to our offscreen
		m_Canvas.drawPath(m_Path, m_Paint);

		// kill this so we don't double draw
		Paint newPaint = new Paint(m_Paint); // Clones the mPaint object
		arrayListPaths.add(new Pair<Path, Paint>(m_Path, newPaint));
		m_Path = new Path();
	}
}