Question

我有三节课。

Input.java（这是gui类）此类通过文本字段获取3个值，并具有触发事件的按钮，最后显示标签以显示值的结果（双值）

package javalearning;

import javax.swing.JOptionPane;


public class Input extends javax.swing.JFrame {

    /**
     * Creates new form Input
     */
    public Input() {
        initComponents();
    }

    /**
     * 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() {

        jPanel1 = new javax.swing.JPanel();
        result_lbl = new javax.swing.JLabel();
        value1 = new javax.swing.JTextField();
        value2 = new javax.swing.JTextField();
        value3 = new javax.swing.JTextField();
        btn1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        result_lbl.setText("jLabel1");

        btn1.setText("jButton1");
        btn1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btn1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(99, 99, 99)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(btn1)
                    .addComponent(result_lbl)
                    .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                        .addComponent(value1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 61, Short.MAX_VALUE)
                        .addComponent(value2, javax.swing.GroupLayout.Alignment.TRAILING)
                        .addComponent(value3, javax.swing.GroupLayout.Alignment.TRAILING)))
                .addContainerGap(100, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addGap(44, 44, 44)
                .addComponent(value1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(value2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(value3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(btn1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(result_lbl)
                .addGap(23, 23, 23))
        );

        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(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(15, Short.MAX_VALUE))
        );

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

    private void btn1ActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
         JOptionPane.showMessageDialog(null, "hello");
         Computation actual_triangle = new Computation(Double.parseDouble(value1.getText()),Double.parseDouble(value2.getText()),Double.parseDouble(value3.getText()));

    }

    public static void main(String args[]) {

        //<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(Input.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Input.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Input.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Input.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new Input().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton btn1;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JLabel result_lbl;
    private javax.swing.JTextField value1;
    private javax.swing.JTextField value2;
    private javax.swing.JTextField value3;
    // End of variables declaration
}

Computation.java 这是计算所有值以产生结果的地方

package javalearning;
public class Computation {

    private double side_a, side_b, side_c,result;


   public Computation(double side_a, double side_b, double side_c)
   {
       this.side_a = side_a;
       this.side_b = side_b;
       this.side_c = side_c;
      valueException ive = new valueException();
      //here if there is a message being sent from the valueException method then the message have to be relayed back to the Input.result_lbl.setText()
      ive.checkvalidation(side_a, side_b, side_c);

   }

   public double getsSide_A()
   {
       return side_a;
   }

   public void setsSide_A(double side_a)
   {
       this.side_a = side_a;
   }

   public double getsSide_B()
   {
       return side_b;
   }

   public void setsSide_B(double side_b)
   {
       this.side_b = side_b;
   }

   public double getsSide_C()
   {
       return side_c;
   }

   public void setsSide_C(double side_c)
   {
       this.side_c = side_c;
   }

   public double calculateArea()
    {
        result = Math.sqrt(side_a*side_b*side_c);
        return result;
    }

}

valueException.java

这是根据用户输入输出各种错误的类，示例1：用户键入一个或所有文本字段的字符串，然后消息将返回到标签类。但这是扭曲，这个类必须从 Computation.java而不是从 Input.java

调用

package javalearning;
public class valueException {

    String message;
    double a_side, b_side,c_side,result;


    public String checkvalidation(double a_side, double b_side, double c_side)
    {
        if((a_side + b_side > c_side)||(a_side + c_side > b_side)||(c_side + b_side > a_side))
        {

           //NOTHING TO DO JUST PROCEED BACK TO COMPUTATION and go the Computation.calculatearea() method

        }

        else
        {
            message = "The values you entered cannot form a shape";
        }
      return message;  
    }

}

问题1：所以我很难弄清楚如何将消息从valueException类中继回到Computation类并从那里传递回Input类？

问题2：如果Input.java中输入的值没有任何问题，那么将进程恢复到Computation类以执行程序的其余部分，因为这是调用valueException类的唯一类，我不确定确切的代码投入。

我已经评论了我遇到问题的问题，我把这些评论放在我认为可以解决的地方。

Answer 1

您有一个视图（Input）和一个模型（Computation）。您需要Controller坐在两者之间，并知道如何处理下一步该做什么。这将完成MVC模式。

Controller将接受来自View的事件，验证和打包输入值，编组服务和Model个对象以完成用例，并决定下一个View的内容应该基于用例的结果。

考虑面向服务的体系结构：控制器可以调用以实现用例的基于接口的服务。我认为最好将用例封装在服务而不是控制器中，因为控制器往往与特定的视图紧密相关。如果您决定使用基于Web的View，则必须在没有服务的情况下重新启动，但如果您拥有这些视图，则新的Web（或移动或平板电脑）控制器可以简单地访问您的服务层并继续嗡嗡声

更新：

好的，在看完你对“简单”的抗议之后，这就是我的建议。我认为问题是你的异常类。你已经把它写成了验证器类。我认为如果我推荐的控制器完成其工作并发现无效情况，你应该只抛出该异常。

package controller;

// Making the Controller the ActionListener is the key.  Take it away from the View.
public class ShapeController implements ActionListener {
    private Input inputView;

    public Controller() {
        this.inputView = new Input();
        this.addActionListener(this);  // Make the Controller respond to action events from the View.
    }

    public void actionPerformed(ActionEvent e) {
        double a_side, b_side, c_side;
        // Get the input values from the input view
        if((a_side + b_side > c_side)||(a_side + c_side > b_side)||(c_side + b_side > a_side)) {
            Computation comp = new Computation()
           // perform your calculation; all is well    
        } else {
            // Problem; throw an exception
            throw new InvalidShapeException();
        }
        // figure out where to go next
    }
}

我认为你的value_exception类是错误的。如上所示使用它并像这样写：

package controller;

public class InvalidShapeException extends RuntimeException {
    // Add whatever you want for messages and details.
    public InvalidShapeException() { super(); }
    public InvalidShapeException(String s) { super(s); }
    public InvalidShapeException(Throwable t) { super(t); }
    public InvalidShapeExceptionI(String s, Throwable t) { super(s, t); }
}

Answer 2

我认为你感到困惑的原因是因为，你不确定如何在类之间传递值。既然你说你开始学习编程（感谢你）。但是你已经抓住每一个机会学习和探索新事物，但不要过多，因为这可能会使你偏离目标。那么你可以为你做些什么问题1：您可以将消息从异常类中继回计算类，然后再次中继回输入类

问题2：一个简单的休息;将断开语句并将控制返回到此循环的代码的原始点，或者在您的情况下将其调用的类。

我假设您知道如何编写其余的代码。

传递来自另一个类的值

2 个答案: