android/4-3-MultipleViews/mvc2/settings.gradle

+include ':app'

android/readme.md

+## Android Demos
+
+> Note: all code requires [Android Studio](https://developer.android.com/studio) to compile and run
+
+

java/2-8-Transformation/BarExercise.java

@@ -34,21 +34,17 @@ public class BarExercise {
 
 class Canvas extends JComponent {
 
-	// the house shape (model position is centred at top left corner)
-	private Polygon shape = new Polygon(new int[] { -50, 50,  50, 	0, -50}, 
-										new int[] { 75,  75, -25, -75, -25}, 5);
-
 	int step = 0;
 
 	Canvas() {
 
 		// only mouse clicked events
 		addMouseListener(new MouseAdapter() { 
-	          public void mouseClicked(MouseEvent me) { 
+            public void mouseClicked(MouseEvent me) { 
 	          	step ++;
 	        	repaint();
-	          } 
-	        }); 
+            } 
+        }); 
 	}
     
     // custom graphics drawing 
@@ -68,11 +64,12 @@ class Canvas extends JComponent {
     	// save the current transform matrix 
     	AffineTransform M = g2.getTransform();    	
 
-    	// the shape will get transformed into "world" coordinates
+    	// transfrom at one time
     	if (true) {
     		g2.translate(50, 100);
 	    	g2.rotate(Math.toRadians(30));
 	    	g2.translate(-50, -100);
+
 	    	g2.setColor(Color.BLUE.darker());
 	    	drawBar(g2, 50, 100, 150, 100);	
 
@@ -82,23 +79,23 @@ class Canvas extends JComponent {
     		switch (step % 4) {
 
     		case 1:
-    		g2.translate(-50, -100);
-	    	drawBar(g2, 50, 100, 150, 100); 
-	    	g2.setTransform(M);
-	    	break;
+        		g2.translate(-50, -100);
+    	    	drawBar(g2, 50, 100, 150, 100); 
+    	    	g2.setTransform(M);
+    	    	break;
     		case 2:
-	    	g2.rotate(Math.toRadians(30));
-	    	g2.translate(-50, -100);
-	    	drawBar(g2, 50, 100, 150, 100);
-	    	g2.setTransform(M);
-	    	break;
+    	    	g2.rotate(Math.toRadians(30));
+    	    	g2.translate(-50, -100);
+    	    	drawBar(g2, 50, 100, 150, 100);
+    	    	g2.setTransform(M);
+    	    	break;
     		case 3:
-	    	g2.translate(50, 100);
-	    	g2.rotate(Math.toRadians(30));
-	    	g2.translate(-50, -100);
-	    	drawBar(g2, 50, 100, 150, 100);	
-	    	g2.setTransform(M);
-	    	break;
+    	    	g2.translate(50, 100);
+    	    	g2.rotate(Math.toRadians(30));
+    	    	g2.translate(-50, -100);
+    	    	drawBar(g2, 50, 100, 150, 100);	
+    	    	g2.setTransform(M);
+    	    	break;
     		}
     	} 
     }

java/2-8-Transformation/Transform2.java

@@ -54,7 +54,7 @@ class Canvas extends JComponent {
     	
     	// the shape will get transformed when rendered
 		g2.translate(M.x, M.y);
-		g2.rotate(45);
+		g2.rotate(Math.toRadians(45));
 		g2.scale(2, 1);
 
      	g2.setStroke(new BasicStroke(3)); 

java/2-8-Transformation/shapemodel/Shape.java

@@ -27,6 +27,7 @@ class Shape {
 
     // add a point to end of shape
     public void addPoint(double x, double y) {
+        if (points == null) clearPoints();
         addPoint(new Point2d(x, y));  
     }
 
@@ -78,9 +79,16 @@ class Shape {
 
     // shape's transform
 
-    // quick hack, get and set would be better
     float scale = 1.0f;
 
+    public float getScale(){
+        return scale;
+    }
+
+    public void setScale(float scale){
+        this.scale = scale;
+    }
+
     // some optimization to cache points for drawing
     Boolean pointsChanged = false; // dirty bit
     int[] xpoints, ypoints;
@@ -129,7 +137,7 @@ class Shape {
         }
 
         // reset the transform to what it was before we drew the shape
-        g2.setTransform(M);            
+//        g2.setTransform(M);            
     }
     
    

java/2-8-Transformation/shapemodel/ShapeDemo.java

@@ -23,12 +23,12 @@ public class ShapeDemo extends JPanel {
 
                 shape = new Shape();
                 // change shape type
-                // shape.setIsClosed(true);
-                // shape.setIsFilled(true);
+//                shape.setIsClosed(true);
+//                shape.setIsFilled(true);
                 shape.setColour(Color.BLUE);
 
                 // try setting scale to something other than 1 
-                shape.scale = 1.0f;
+                shape.setScale(1.0f);
 
                 repaint();
             }
@@ -57,7 +57,7 @@ public class ShapeDemo extends JPanel {
         Graphics2D g2 = (Graphics2D) g; // cast to get 2D drawing methods
         g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,  // antialiasing look nicer
                             RenderingHints.VALUE_ANTIALIAS_ON);
- 
+
         if (shape != null)
             shape.draw(g2);
     }

java/2-9-HitTest/ClosestPoint.java

+/*
+* CS 349 Java Code Examples
+*
+* ClosestPoint    Uses two methods to compute distance from 
+                      mouse to closest point on line. Double click
+                      to generate new line.
+*
+*/
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+
+import java.awt.event.MouseMotionAdapter;
+import java.awt.event.MouseAdapter;
+
+import java.awt.*;
+import java.awt.event.MouseEvent;
+import java.awt.geom.*;
+import java.util.ArrayList;
+import javax.vecmath.*;
+import java.lang.Math.*;
+import java.util.Random;
+
+// create the window and run the demo
+public class ClosestPoint extends JPanel {
+
+	Point P0 = new Point();
+	Point P1 = null;
+	Point M = new Point(); // mouse point
+
+    public static void main(String[] args) {
+        // create the window        
+        ClosestPoint canvas = new ClosestPoint();
+        JFrame f = new JFrame("ClosestPoint"); // jframe is the app window
+        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        f.setSize(400, 400); // window size
+        f.setContentPane(canvas); // add canvas to jframe    
+        f.setVisible(true); // show the window
+    }    
+
+	ClosestPoint() {     
+		setBackground(Color.WHITE);
+        // add listeners
+        addMouseListener(new MouseAdapter(){
+            public void mouseClicked(MouseEvent arg0) {                
+                // generate new line on double click
+                if (arg0.getClickCount() == 2)  
+                    randomLine();
+                repaint();
+            }
+        });
+
+        addMouseMotionListener(new MouseMotionAdapter(){
+            public void mouseMoved(MouseEvent arg0) {
+                // TODO Auto-generated method stub
+                M.x = arg0.getX();
+                M.y = arg0.getY();
+                repaint();                
+            }            
+        });
+    }
+    
+    // custom graphics drawing 
+    public void paintComponent(Graphics g) {
+    	super.paintComponent(g); // JPanel paint
+    	Graphics2D g2 = (Graphics2D)g;
+
+        if (P1 == null) {
+            P1 = new Point();
+            randomLine();
+        }
+    	
+    	// antiliasing
+    	g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
+    	        RenderingHints.VALUE_ANTIALIAS_ON);
+    	
+    	g2.setStroke(new BasicStroke(2));
+    	
+    	// draw line
+    	g2.setColor(Color.BLACK);
+    	g2.drawLine(P0.x, P0.y, P1.x, P1.y);
+    	
+    	// draw mouse point
+    	g2.setColor(Color.BLACK);
+    	int s = 7;
+    	g2.drawOval(M.x - s, M.y - s, 2 * s, 2 * s );
+    	
+    	// get closest point using the vector projection method
+    	Point2d M2 = new Point2d(M.x, M.y);
+		Point2d I1 = closestPoint(M2, 
+				    			new Point2d(P0.x, P0.y),
+				    			new Point2d(P1.x, P1.y));
+	 
+    	// draw closest point
+    	g2.setColor(Color.RED);
+    	g2.drawOval((int)I1.x - s, (int)I1.y - s, 2 * s, 2 * s );
+    	
+    	// use that to get distance
+		double d1 = M2.distance(I1);
+
+    	// get distance using Java2D method
+    	double d2 = Line2D.ptSegDist(P0.x, P0.y, P1.x, P1.y, M.x, M.y);
+    	
+    	g2.setColor(Color.BLACK);
+    	g2.drawString(String.format("%.1f %.1f", d1, d2), M.x + 10,M.y);
+    }
+    
+    // find closest point using projection method 
+    static Point2d closestPoint(Point2d M, Point2d P0, Point2d P1) {
+    	Vector2d v = new Vector2d();
+    	v.sub(P1,P0); // v = P1 - P0
+    	
+    	// early out if line is less than 1 pixel long
+    	if (v.lengthSquared() < 0.5)
+    		return P0;
+    	
+    	Vector2d u = new Vector2d();
+    	u.sub(M,P0); // u = M - P1
+
+    	// scalar of vector projection ...
+    	double s = u.dot(v) / v.dot(v); 
+    	
+    	// find point for constrained line segment
+    	if (s < 0) 
+    		return P0;
+    	else if (s > 1)
+    		return P1;
+    	else {
+    		Point2d I = P0;
+        	Vector2d w = new Vector2d();
+        	w.scale(s, v); // w = s * v
+    		I.add(w); // I = P0 + w
+    		return I;
+    	}
+    }
+    
+    // random numbers
+    static Random rand = new Random();
+    
+    int random(int min, int max) {
+    	return rand.nextInt(max - min + 1) + min;
+    }
+    
+    void randomLine()
+    {
+		// create random line
+		int m = 50; // margin
+		P0.x = m;
+		P0.y = random(m,  getHeight() - m);
+		P1.x = getWidth() - m;
+		P1.y = random(m, getHeight() - m);	
+    }
+
+}

java/2-9-HitTest/PolygonHittest.java

+/*
+* CS 349 Java Code Examples
+*
+* PolygonHittest  Uses built-in method to hit-test closed polygon.
+*
+*/
+import java.awt.*;
+import java.awt.event.*;
+import java.awt.geom.*;
+import javax.swing.*;
+
+public class PolygonHittest extends JPanel{
+
+	Point M = new Point(); // mouse point
+	Polygon poly = new Polygon();
+
+	public static void main(String args[]){
+		JFrame window = new JFrame("PolygonHittest");
+		window.setSize(300, 300);
+		window.setContentPane(new PolygonHittest());
+		window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+		window.setVisible(true);
+	}
+
+	public PolygonHittest(){
+		this.addMouseListener(new MouseAdapter(){
+			public void mouseClicked(MouseEvent e){
+				poly.addPoint(e.getX(), e.getY());
+				repaint();
+			}
+		});
+
+        this.addMouseMotionListener(new MouseAdapter(){
+            public void mouseMoved(MouseEvent e){
+                M.x = e.getX();
+                M.y = e.getY();
+                repaint();
+            }
+        }); 
+
+	}
+
+    public void paintComponent(Graphics g) {
+        super.paintComponent(g);
+        Graphics2D g2 = (Graphics2D) g;  
+
+		if (poly.contains(M.x, M.y))
+			g2.setColor(Color.BLUE);
+		else
+			g2.setColor(Color.RED);
+
+        g2.fillPolygon(poly);
+
+		g2.setColor(Color.BLACK);
+		g.drawPolyline(poly.xpoints, poly.ypoints, poly.npoints);
+
+	}
+}

java/2-9-HitTest/TransformHittest.java

+/*
+* CS 349 Java Code Examples
+*
+* CompositionOrder        Demo of different concatenation orders of matrix transforms.
+*                    Click the window to change the order.
+*
+*/
+import javax.swing.JFrame;
+import javax.swing.JComponent;
+import java.awt.*;
+import java.awt.geom.*;
+import java.lang.Math.*;
+import java.awt.event.*;
+
+// create the window and run the demo
+public class TransformHittest {
+    
+    public static void main(String[] args) {
+        // create the window        
+        Canvas canvas = new Canvas();
+        JFrame f = new JFrame("CompositionOrder"); // jframe is the app window
+        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        f.setSize(500, 700); // window size
+        f.setContentPane(canvas); // add canvas to jframe   
+        f.setBackground(Color.WHITE);       
+        f.setVisible(true); // show the window
+    }
+} 
+
+class Canvas extends JComponent {
+
+    Point M = new Point(); // mouse point
+
+    AffineTransform AT1;    // transform matrix for shape1
+    AffineTransform AT2;    // transform matrix for shape2
+
+    
+    // the house shape (model position is centred at top left corner)
+    private Polygon shape = new Polygon(new int[] { -50, 50,  50,   0, -50}, 
+                                        new int[] { 75,  75, -25, -75, -25}, 5);
+
+    // a larger font for displaying the concatenation order
+    private Font font = new Font("SansSerif", Font.PLAIN, 30);
+
+    // the concatenation order
+    private int order = 0;
+
+    Canvas() {
+        
+        // create transformation matrix for shape1
+        AT1 = new AffineTransform();
+        AT1.translate(350, 100);
+        AT1.rotate(Math.toRadians(30));
+
+        // create another transformation matrix for shape2
+        AT2 = new AffineTransform();
+        AT2.translate(200, 300);
+        AT2.rotate(Math.toRadians(30));
+        AT2.scale(2, 2);
+
+        this.addMouseMotionListener(new MouseAdapter(){
+            public void mouseMoved(MouseEvent e){
+                M.x = e.getX();
+                M.y = e.getY();
+                repaint();
+            }
+        }); 
+        
+        System.out.println("click to change transformation composition order");
+    }
+    
+    // custom graphics drawing 
+    public void paintComponent(Graphics g) {
+        super.paintComponent(g); // JPanel paint
+        Graphics2D g2 = (Graphics2D)g;
+        
+        // save the current transform matrix 
+        AffineTransform ATG = g2.getTransform();
+        
+        // draw the original shape in "model" coordinates
+        g2.setColor(Color.BLACK);
+        g2.setStroke(new BasicStroke(3));
+        g2.drawPolygon(shape.xpoints, shape.ypoints, shape.npoints);
+        
+
+        // Shape1                
+        g2.setTransform(AT1);    // Use Transform Matrix AT1 for shape1
+        g2.setColor(Color.RED);  
+        g2.drawPolygon(shape.xpoints, shape.ypoints, shape.npoints);
+
+        // hit testing
+        Point MT = new Point();
+        try{
+            // create an inverse matrix of AT1
+            AffineTransform IAT1 = AT1.createInverse();
+            // apply the inverse transformation to the mouse position
+            IAT1.transform(M, MT);
+            // check if original shape contains transformed mouse position
+            if (shape.contains(MT.x, MT.y))
+                g2.setColor(Color.RED);
+            else
+                g2.setColor(Color.WHITE);  
+            g2.fillPolygon(shape);
+        } catch (NoninvertibleTransformException e){
+            // error
+        }
+
+        // Shape2
+        g2.setTransform(AT2);    // Use Transform Matrix AT2 for shape2
+        g2.setColor(Color.BLUE);  
+        g2.drawPolygon(shape.xpoints, shape.ypoints, shape.npoints);
+        // hit test
+        try{
+            // create an inverse matrix of AT2
+            AffineTransform IAT2 = AT2.createInverse();
+            // apply the inverse transformation to the mouse position
+            IAT2.transform(M, MT);
+            // check if original shape contains transformed mouse position
+            if (shape.contains(MT.x, MT.y))
+                g2.setColor(Color.BLUE);
+            else
+                g2.setColor(Color.WHITE);  
+            g2.fillPolygon(shape);
+        } catch (NoninvertibleTransformException e){
+            // error
+        }
+        
+        // reset to transform 
+        g2.setTransform(ATG);
+        
+    }
+}

java/2-9-HitTest/makefile

+# super simple makefile
+# call it using 'make NAME=name_of_code_file_without_extension'
+# (assumes a .java extension)
+NAME = ClosestPoint
+# you may need to pass OS=win to run on windows
+OS = 
+
+# HACK: vecmath is included regardless if needed
+all:
+	@echo "Compiling..."
+	javac -cp vecmath.jar $(NAME).java
+
+run: all
+# windows needs a semicolon
+ifeq ($(OS),win)
+		@echo "Running on windows ..."
+		java -cp "vecmath.jar;." $(NAME)
+# everyone else likes a colon
+else
+		@echo "Running ..."
+		java -cp "vecmath.jar:." $(NAME)
+endif
+
+clean:
+	rm -rf *.class

java/3-0-MVC/hellomvc1/Controller.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+// (C) Joseph Mack 2011, jmack (at) wm7d (dot) net, released under GPL v3 (or any later version)
+
+import java.awt.event.*;
+
+class Controller implements ActionListener {
+
+	Model model;
+
+	Controller(Model model) {
+		this.model = model;
+	}
+
+	// event from the view's button
+	public void actionPerformed(java.awt.event.ActionEvent e){
+		System.out.println("Controller: changing Model");
+		model.incrementCounter();
+	}
+}

java/3-0-MVC/hellomvc1/Main.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+/**
+ * One view.  Separate controller.
+ */
+
+import javax.swing.*;
+import java.awt.Dimension;
+import java.awt.event.*;
+
+public class Main {
+
+	public static void main(String[] args){
+		JFrame frame = new JFrame("HelloMVC1");
+
+		// create Model and initialize it
+		Model model = new Model();
+		// create Controller, tell it about model
+		Controller controller = new Controller(model);
+		// create View, tell it about model and controller
+		View view = new View(model, controller);
+		// tell Model about View.
+		model.setView(view);
+
+		// add view (view is a JPanel)
+		frame.getContentPane().add(view);
+
+		// setup window
+		frame.setPreferredSize(new Dimension(300,300));
+		frame.pack();
+		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+		frame.setVisible(true);
+	}
+}

java/3-0-MVC/hellomvc1/Model.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+// View interface
+interface IView {
+	public void updateView();
+}
+
+public class Model {
+
+	// the data in the model, just a counter
+	private int counter;
+	
+	// the view (note, only supports 1 view!)
+	IView view;
+
+	// set the view observer
+	public void setView(IView view) {
+		this.view = view;
+		// update the view to current state of the model
+		view.updateView();
+	}
+
+	public int getCounterValue() {
+		return counter;
+	}
+
+	public void incrementCounter() {
+		if (counter < 5) {
+			counter++;
+			System.out.println("Model: increment counter to " + counter);
+			notifyObserver();
+		}
+	}
+
+	// notify the IView observer
+	private void notifyObserver() {
+		System.out.println("Model: notify View");
+		view.updateView();
+	}
+}

java/3-0-MVC/hellomvc1/View.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+import javax.swing.*;
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import java.awt.GridBagConstraints;
+import java.awt.GridBagLayout;
+import java.awt.event.*;
+
+class View extends JPanel implements IView {
+
+	// the view's main user interface
+	private JButton button;
+
+	// the model that this view is showing
+	private Model model;
+
+	View(Model model, Controller controller) {
+		
+		// create the view UI
+		button = new JButton("?");
+		button.setMaximumSize(new Dimension(100, 50));
+		button.setPreferredSize(new Dimension(100, 50));
+		// a GridBagLayout with default constraints centres
+		// the widget in the window
+		this.setLayout(new GridBagLayout());
+		this.add(button, new GridBagConstraints());
+
+		// set the model
+		this.model = model;
+		// setup the event to go to the controller
+		button.addActionListener(controller);
+	}
+
+	// IView interface
+	public void updateView() {
+		System.out.println("View: updateView");
+		button.setText(Integer.toString(model.getCounterValue()));
+	}
+} 

java/3-0-MVC/hellomvc1/makefile

+# super simple makefile
+# call it using 'make NAME=name_of_code_file_without_extension'
+# (assumes a .java extension)
+NAME = "Main"
+
+all:
+	@echo "Compiling..."
+	javac *.java
+
+run: all
+	@echo "Running..."
+	java $(NAME)
+
+clean:
+	rm -rf *.class

java/3-0-MVC/hellomvc2/Controller.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+// (C) Joseph Mack 2011, jmack (at) wm7d (dot) net, released under GPL v3 (or any later version)
+
+import java.awt.event.*;
+
+class Controller implements ActionListener, MouseListener {
+
+	Model model;
+
+	Controller(Model model) {
+		this.model = model;
+	}
+
+	// event from the view's button
+	public void actionPerformed(java.awt.event.ActionEvent e){
+		System.out.println("Controller: changing Model (actionPerformed)");
+		model.incrementCounter();
+	}
+
+	public void mouseClicked(MouseEvent e) {
+		System.out.println("Controller: changing Model (mouseClicked)");
+		model.incrementCounter();
+	}
+
+	public void mouseEntered(MouseEvent e) { }
+	public void mouseExited(MouseEvent e) { }
+	public void mousePressed(MouseEvent e) { }
+	public void mouseReleased(MouseEvent e) { }
+
+}

java/3-0-MVC/hellomvc2/Main.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+/**
+ * Two views coordinated with the observer pattern.  Separate controller.
+ * The mechanics of a separate controller are starting to break down.
+ */
+
+import javax.swing.*;
+import java.awt.Dimension;
+import java.awt.GridLayout;
+import java.awt.event.*;
+
+public class Main {
+
+	public static void main(String[] args){
+		JFrame frame = new JFrame("HelloMVC2");
+
+		// create Model and initialize it
+		Model model = new Model();
+		// create Controller, tell it about model
+		Controller controller = new Controller(model);
+		// create View, tell it about model and controller
+		View view = new View(model, controller);
+		// tell Model about View
+		model.addView(view);
+
+		// create second view ...
+		View2 view2 = new View2(model, controller);
+		model.addView(view2);
+
+		// create a layout panel to hold the two views
+		JPanel p = new JPanel(new GridLayout(2,1));
+		frame.getContentPane().add(p);
+
+		// add views (each view is a JPanel)
+		p.add(view);
+		p.add(view2);
+
+		// setup the window
+		frame.setPreferredSize(new Dimension(300,300));
+		frame.pack();
+		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+		frame.setVisible(true);
+	}
+}

java/3-0-MVC/hellomvc2/Model.java

+import java.util.ArrayList;
+
+// HelloMVC: a simple MVC example
+// the model is just a counter 
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+// View interface
+interface IView {
+	public void updateView();
+}
+
+public class Model {	
+
+	// the data in the model, just a counter
+	private int counter;	
+	
+	// all views of this model
+	private ArrayList<IView> views = new ArrayList<IView>();
+	
+	// set the view observer
+	public void addView(IView view) {
+		views.add(view);
+		view.updateView();
+	}
+	
+	public int getCounterValue() {
+		return counter;
+	}
+	
+	public void incrementCounter() {
+		if (counter < 5) {
+			counter++;
+			System.out.println("Model: increment counter to " + counter);
+			notifyObservers();
+		}
+	} 	
+	
+	// notify the IView observer
+	private void notifyObservers() {
+		for (IView view : this.views) {
+			System.out.println("Model: notify View");
+			view.updateView();
+		}
+	}
+}

java/3-0-MVC/hellomvc2/View.java

+// HelloMVC: a simple MVC example
+// the model is just a counter
+// inspired by code by Joseph Mack, http://www.austintek.com/mvc/
+
+import javax.swing.*;
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import java.awt.GridBagConstraints;
+import java.awt.GridBagLayout;
+import java.awt.event.*;
+
+class View extends JPanel implements IView {
+
+	// the view's main user interface
+	private JButton button;
+
+	// the model that this view is showing
+	private Model model;
+
+	View(Model model, Controller controller) {
+		
+		// create the view UI
+		button = new JButton("?");
+		button.setMaximumSize(new Dimension(100, 50));
+		button.setPreferredSize(new Dimension(100, 50));
+		// a GridBagLayout with default constraints centres
+		// the widget in the window
+		this.setLayout(new GridBagLayout());
+		this.add(button, new GridBagConstraints());
+
+		// set the model
+		this.model = model;
+		// setup the event to go to the controller
+		button.addActionListener(controller);
+	}
+
+	// IView interface
+	public void updateView() {
+		System.out.println("View: updateView");
+		button.setText(Integer.toString(model.getCounterValue()));
+	}
+}