Question

JAVA question here, and thank you. I need ot update the following classes an fixme's on this.canvas = null etc.

Thanks!

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import edu.luc.etl.cs313.android.shapes.model.*;

/**
 * A Visitor for drawing a shape to an Android canvas.
 */
public class Draw implements Visitor<Void> {

   // TODO entirely your job (except onCircle)

   private final Canvas canvas;

   private final Paint paint;

   public Draw(final Canvas canvas, final Paint paint) {
      this.canvas = null; // FIXME
      this.paint = null; // FIXME
      paint.setStyle(Style.STROKE);
   }

   @Override
   public Void onCircle(final Circle c) {
      canvas.drawCircle(0, 0, c.getRadius(), paint);
      return null;
   }

   @Override
   public Void onStrokeColor(final StrokeColor c) {

      return null;
   }

   @Override
   public Void onFill(final Fill f) {

      return null;
   }

   @Override
   public Void onGroup(final Group g) {

      return null;
   }

   @Override
   public Void onLocation(final Location l) {

      return null;
   }

   @Override
   public Void onRectangle(final Rectangle r) {

      return null;
   }

   @Override
   public Void onOutline(Outline o) {

      return null;
   }

   @Override
   public Void onPolygon(final Polygon s) {

      final float[] pts = null;

      canvas.drawLines(pts, paint);
      return null;
   }
}

Answer 1

// Source Code:

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import edu.luc.etl.cs313.android.shapes.model.*;
import java.util.Iterator;
import java.util.List;


/**
 * A Visitor for drawing a shape to an Android canvas.
 */
public class Draw implements Visitor<Void> {

    private final Canvas canvas;

    private final Paint paint;

    public Draw(final Canvas canvas, final Paint paint) {
        this.canvas = canvas;
        this.paint = paint;
        paint.setStyle(Style.STROKE);
    }

    @Override
    public Void onCircle(final Circle c) {
        canvas.drawCircle(0, 0, c.getRadius(), paint);
        return null;
    }

    @Override
    public Void onStrokeColor(final StrokeColor c) {
        final int x = paint.getColor();
        paint.setColor(c.getColor());
        c.getShape().accept(this);
        paint.setColor(x);
        return null;
    }

    @Override
    public Void onFill(final Fill f) {
        final Style a = paint.getStyle();
        paint.setStyle(Style.FILL_AND_STROKE);
        f.getShape().accept(this);
        paint.setStyle(a);
        return null;
    }

    @Override
    public Void onGroup(final Group g) {
        final Iterator<? extends Shape > shape = g.getShapes().iterator();
        while (shape.hasNext()) {
            shape.next().accept(this);
        }
        return null;
    }

    @Override
    public Void onLocation(final Location l) {
        canvas.translate(l.getX(), l.getY());
        l.getShape().accept(this);
        canvas.translate(-l.getX(), -l.getY());
        return null;
    }

    @Override
    public Void onRectangle(final Rectangle r) {
        canvas.drawRect(0, 0, r.getWidth(), r.getHeight(), paint);
        return null;
    }

    @Override
    public Void onOutline(Outline o) {
        final Style before = paint.getStyle();
        paint.setStyle(Style.STROKE);
        o.getShape().accept(this);
        paint.setStyle(before);
        return null;
    }

    @Override
    public Void onPolygon(final Polygon s) {
        List<? extends Point> points = s.getPoints();
        final float[] pts =
                {
                        points.get(0).getX(), points.get(0).getY(),
                        points.get(1).getX(), points.get(1).getY(),
                        points.get(1).getX(), points.get(1).getY(),
                        points.get(2).getX(), points.get(2).getY(),
                        points.get(2).getX(), points.get(2).getY(),
                        points.get(3).getX(), points.get(3).getY(),
                        points.get(0).getX(), points.get(0).getY(),
                };
        canvas.drawLines(pts, paint);
        return null;
    }
}