JAVA MVC_以MVC架構來進行Java GUI程式開發(二)_建構簡單的四則運算計算器_model中負責計算

於前一篇大致上介紹到MVC核心理念

這裡要對於Model運算部分做一個加強示範

於上一篇示範練習比較強調在於Controller的溝通

這篇我們要來練習簡單四則運算中
別於以往的嵌入介面層設計我們把計算的流程定義於Model當中
於Controller中去呼叫做計算然後再更新顯示給View



CalculatorModel.java


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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.cal.Model;

/**
 *
 * @author chous
 */
public class CalculatorModel {
    private int calculationVal;
    
    public void addTwoNums(int firstNum,int secondNum){
        calculationVal = firstNum + secondNum;
    }
    
    public int getCalculationValue(){
        return calculationVal;
    }
}



CalculatorView.java


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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.cal.View;

import java.awt.event.ActionListener;
import javax.swing.JOptionPane;

/**
 *
 * @author chous
 */
public class CalculatorView extends javax.swing.JFrame {

    /**
     * Creates new form CalculatorView
     */
    public CalculatorView() {
        initComponents();
    }
    
    public int getFirstNum(){
        return Integer.parseInt(this.txtNum1.getText());
    }
    
    public int getSecondNum(){
        return Integer.parseInt(this.txtNum2.getText());
    }
    
    public int getCalcResult(){
        return Integer.parseInt(this.lblResult.getText());
    }

    public void setCalcResult(int res){
        this.lblResult.setText(Integer.toString(res));
    }
    
    public void addCalcListener(ActionListener listenCalButton){
        this.btnCal.addActionListener(listenCalButton);
    }
    
    public void displayErrorMessage(String msg){
        JOptionPane.showMessageDialog(this, msg);
    }
    
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        txtNum1 = new javax.swing.JTextField();
        txtNum2 = new javax.swing.JTextField();
        jLabel1 = new javax.swing.JLabel();
        btnCal = new javax.swing.JButton();
        lblResult = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("+");

        btnCal.setText("Calculate");

        lblResult.setText("___");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(txtNum1, javax.swing.GroupLayout.PREFERRED_SIZE, 177, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(jLabel1)
                .addGap(23, 23, 23)
                .addComponent(txtNum2, javax.swing.GroupLayout.PREFERRED_SIZE, 166, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(btnCal)
                .addGap(31, 31, 31)
                .addComponent(lblResult, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(80, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(44, 44, 44)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(txtNum1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txtNum2)
                    .addComponent(jLabel1)
                    .addComponent(btnCal)
                    .addComponent(lblResult))
                .addContainerGap(284, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    /**
     * @param args the command line arguments
     */
//    public static void main(String args[]) {
//        /* Set the Nimbus look and feel */
//        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
//        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
//         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
//         */
//        try {
//            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
//                if ("Nimbus".equals(info.getName())) {
//                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
//                    break;
//                }
//            }
//        } catch (ClassNotFoundException ex) {
//            java.util.logging.Logger.getLogger(CalculatorView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
//        } catch (InstantiationException ex) {
//            java.util.logging.Logger.getLogger(CalculatorView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
//        } catch (IllegalAccessException ex) {
//            java.util.logging.Logger.getLogger(CalculatorView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
//        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
//            java.util.logging.Logger.getLogger(CalculatorView.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
//        }
//        //</editor-fold>
//
//        /* Create and display the form */
//        java.awt.EventQueue.invokeLater(new Runnable() {
//            public void run() {
//                new CalculatorView().setVisible(true);
//            }
//        });
//    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton btnCal;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel lblResult;
    private javax.swing.JTextField txtNum1;
    private javax.swing.JTextField txtNum2;
    // End of variables declaration                   
}

CalculatorController.java


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/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.cal.Controller;

import com.cal.Model.CalculatorModel;
import com.cal.View.CalculatorView;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

/**
 *
 * @author chous
 */
public class CalculatorController {

    private CalculatorModel m;
    private CalculatorView v;

    public CalculatorController(CalculatorModel m, CalculatorView v) {
        this.m = m;
        this.v = v;
        this.v.setVisible(true);
        this.v.addCalcListener(new CalcListener());
    }

    class CalcListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            int n1, n2 = 0;
            try {
                n1 = v.getFirstNum();
                n2 = v.getSecondNum();
                m.addTwoNums(n1, n2);
                v.setCalcResult(m.getCalculationValue());
            }catch(NumberFormatException ex){
                v.displayErrorMessage("Please enter two integers");
            }
        }

    }

}































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