How can user paint or draw line on shape by touch

Question

I want to create an app which shows picture something like hand of human and user can draw a line on it. e.g something like you want to paint the hand or paint the lines of the hand on given picture.

I create the shape of hand without layout file as shown in below code.

I don't know how can possible for a user to drawing or paint on that shape by touch.

Can anyone help me to achieve this!!?.

Thank you in Advance.

Here's my code:

 public class YeknafareActivity_layout extends View {

    Paint black_paintbrushstroke;
    Path Hand;


    public YeknafareActivity_layout(Context context) {
        super(context);

    }


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);


        black_paintbrushstroke = new Paint();
        black_paintbrushstroke.setColor(Color.BLACK);
        black_paintbrushstroke.setStyle(Paint.Style.STROKE);
        black_paintbrushstroke.setStrokeWidth(4);


        Hand = new Path();
        Hand.moveTo(225, 844);  // A
        Hand.lineTo(191, 675);

        Hand.moveTo(191, 675);  // B
        Hand.lineTo(114, 412);

        Hand.moveTo(114, 412); // C
        Hand.lineTo(147, 409);

        Hand.moveTo(147, 409); // D
        Hand.lineTo(235, 591);

        Hand.moveTo(235, 591); // E
        Hand.lineTo(179, 279);

        Hand.moveTo(179, 279); // F
        Hand.lineTo(222, 279);

        Hand.moveTo(222, 279); // G
        Hand.lineTo(300, 534);

        Hand.moveTo(300, 534); // H
        Hand.lineTo(308, 186);

        Hand.moveTo(308, 186); // I
        Hand.lineTo(341, 187);

        Hand.moveTo(341, 187); // J
        Hand.lineTo(382, 513);

        Hand.moveTo(382, 513); // K
        Hand.lineTo(427, 212);

        Hand.moveTo(427, 212); // L
        Hand.lineTo(460, 216);

        Hand.moveTo(460, 216); // M
        Hand.lineTo(462, 536);

        Hand.moveTo(462, 536); // O
        Hand.lineTo(476, 613);

        Hand.moveTo(476, 613); // P
        Hand.lineTo(507, 662);

        Hand.moveTo(507, 662); // Q
        Hand.lineTo(593, 501);

        Hand.moveTo(593, 501); // R
        Hand.lineTo(628, 492);

        Hand.moveTo(628, 492); // S
        Hand.lineTo(645, 511);

        Hand.moveTo(645, 511); // T
        Hand.lineTo(470, 960);

        Hand.moveTo(470, 960); // U
        Hand.lineTo(386, 989);

        Hand.moveTo(386, 989); // V
        Hand.lineTo(280, 947);

        Hand.lineTo(225, 844);


        canvas.drawPath(Hand, black_paintbrushstroke);

Answer 1

Finally, I find the answer by myself, Here is the solution:

after declaring Path & Paint, you can use below code, so that you can draw anything on the screen:

@Override
public boolean onTouchEvent(MotionEvent event) {
    float xpos = event.getX();
    float ypos = event.getY();

    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(xpos, ypos);
            return true;
        case MotionEvent.ACTION_MOVE:
            path.lineTo(xpos, ypos);
            break;
        case MotionEvent.ACTION_UP:
            break;
        default:
            return false;
    }
    invalidate();
    return true;
}

It works for me :)