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Saturday 20 July 2013

CalculatorModel.java
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02// and that is it. It doesn't know the View
03// exists
04 
05public class CalculatorModel {
06 
07    // Holds the value of the sum of the numbers
08    // entered in the view
09     
10    private int calculationValue;
11     
12    public void addTwoNumbers(int firstNumber, int secondNumber){
13         
14        calculationValue = firstNumber + secondNumber;
15         
16    }
17    
18    public int getCalculationValue(){
19         
20        return calculationValue;
21         
22    }
23     
24}

CalculatorView.java
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01// This is the View
02// Its only job is to display what the user sees
03// It performs no calculations, but instead passes
04// information entered by the user to whomever needs
05// it.
06 
07import java.awt.event.ActionListener;
08 
09import javax.swing.*;
10 
11public class CalculatorView extends JFrame{
12 
13    private JTextField firstNumber  = new JTextField(10);
14    private JLabel additionLabel = new JLabel("+");
15    private JTextField secondNumber = new JTextField(10);
16    private JButton calculateButton = new JButton("Calculate");
17    private JTextField calcSolution = new JTextField(10);
18     
19    CalculatorView(){
20         
21        // Sets up the view and adds the components
22         
23        JPanel calcPanel = new JPanel();
24         
25        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
26        this.setSize(600, 200);
27         
28        calcPanel.add(firstNumber);
29        calcPanel.add(additionLabel);
30        calcPanel.add(secondNumber);
31        calcPanel.add(calculateButton);
32        calcPanel.add(calcSolution);
33         
34        this.add(calcPanel);
35         
36        // End of setting up the components --------
37         
38    }
39     
40    public int getFirstNumber(){
41         
42        return Integer.parseInt(firstNumber.getText());
43         
44    }
45     
46    public int getSecondNumber(){
47         
48        return Integer.parseInt(secondNumber.getText());
49         
50    }
51     
52    public int getCalcSolution(){
53         
54        return Integer.parseInt(calcSolution.getText());
55         
56    }
57     
58    public void setCalcSolution(int solution){
59         
60        calcSolution.setText(Integer.toString(solution));
61         
62    }
63     
64    // If the calculateButton is clicked execute a method
65    // in the Controller named actionPerformed
66     
67    void addCalculateListener(ActionListener listenForCalcButton){
68         
69        calculateButton.addActionListener(listenForCalcButton);
70         
71    }
72     
73    // Open a popup that contains the error message passed
74     
75    void displayErrorMessage(String errorMessage){
76         
77        JOptionPane.showMessageDialog(this, errorMessage);
78         
79    }
80     
81}

CalculatorController.java
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01import java.awt.event.ActionEvent;
02import java.awt.event.ActionListener;
03 
04// The Controller coordinates interactions
05// between the View and Model
06 
07public class CalculatorController {
08     
09    private CalculatorView theView;
10    private CalculatorModel theModel;
11     
12    public CalculatorController(CalculatorView theView, CalculatorModel theModel) {
13        this.theView = theView;
14        this.theModel = theModel;
15         
16        // Tell the View that when ever the calculate button
17        // is clicked to execute the actionPerformed method
18        // in the CalculateListener inner class
19         
20        this.theView.addCalculateListener(new CalculateListener());
21    }
22     
23    class CalculateListener implements ActionListener{
24 
25        public void actionPerformed(ActionEvent e) {
26             
27            int firstNumber, secondNumber = 0;
28             
29            // Surround interactions with the view with
30            // a try block in case numbers weren't
31            // properly entered
32             
33            try{
34             
35                firstNumber = theView.getFirstNumber();
36                secondNumber = theView.getSecondNumber();
37                 
38                theModel.addTwoNumbers(firstNumber, secondNumber);
39                 
40                theView.setCalcSolution(theModel.getCalculationValue());
41             
42            }
43 
44            catch(NumberFormatException ex){
45                 
46                System.out.println(ex);
47                 
48                theView.displayErrorMessage("You Need to Enter 2 Integers");
49                 
50            }
51             
52        }
53         
54    }
55     
56}

MVCCalculator.java
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01public class MVCCalculator {
02     
03    public static void main(String[] args) {
04         
05        CalculatorView theView = new CalculatorView();
06         
07        CalculatorModel theModel = new CalculatorModel();
08         
09        CalculatorController theController = new CalculatorController(theView,theModel);
10         
11        theView.setVisible(true);
12         
13    }
14}

http://www.newthinktank.com/2013/02/mvc-java-tutorial/
- See more at: http://www.newthinktank.com/2013/02/mvc-java-tutorial/#sthash.uSKCsfhx.dpuf
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