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Java swing（netbeans）用于计算器错误的单独类

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对于学校项目，我必须创建一个基本计算器，其功能包括加法，除法等 . 此计算器还必须包含一个打开网站的按钮 . 打开网站的计算器和按钮必须位于同一个计算器上 . 但是，在不同的 class . 对于这个项目，我使用的是Netbeans，特别是用于设计和源代码的JFrame表单 . 我不是非常了解Java和Java，我只是围绕打开网站的按钮的方法创建了一个类 .

这造成了两个问题：1 . 在@SurpressWarnings（“未选中”）中，我收到了一个错误：

jButton20.setIcon(new javax.swing.ImageIcon(getClass().getResource("/googleonlineretry.jpg"))); // NOI18N
    jButton20.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton20ActionPerformed(evt);
        }

jButton20是（点击时）打开网站链接的按钮 . 为了测试我使用谷歌 . 在围绕该方法的类中，我得到一条灰色（灰色/灰色，无论如何）线，表示该方法未被使用，并且“evt”也未被使用 . 这是我正在谈论的课程：

class Pickone extends RekenMachine {


private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {                                          
       Desktop browser = Desktop.getDesktop();
    try {
   browser.browse(new URI("http://google.com"));

   }
  catch(IOException err) {
  }

   catch (URISyntaxException err) {
   }

}

行：private void jButton20ActionPerformed（java.awt.event.ActionEvent evt）是通过单击Netbeans设计位中的按钮自动创建的 .

我的主要问题，或者更确切地说是请求，是要弄清楚如何在这个项目中有两个类 . 我花了整整一夜试图解决这个问题 . 在线阅读，查看我的书，但无法理解 .

计算器看起来像这样：Image of what it looks like

这是完整的源代码，fwi，RekenMachine =计算器和RekenUitslag =文本字段 .

public class RekenMachine extends javax.swing.JFrame {
int eersteNummer, tweedeNummer, resultaat;
String   Operator, ingevuld, antwoord;
String calculation;

public RekenMachine() {
    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();
    jPanel2 = new javax.swing.JPanel();
    RekenUitslag = new javax.swing.JTextField();
    jButton4 = new javax.swing.JButton();
    jButton5 = new javax.swing.JButton();
    jButton6 = new javax.swing.JButton();
    jButton7 = new javax.swing.JButton();
    jButton8 = new javax.swing.JButton();
    jButton9 = new javax.swing.JButton();
    jButton10 = new javax.swing.JButton();
    jButton11 = new javax.swing.JButton();
    jButton12 = new javax.swing.JButton();
    jButton13 = new javax.swing.JButton();
    jButton14 = new javax.swing.JButton();
    jButton15 = new javax.swing.JButton();
    jButton16 = new javax.swing.JButton();
    jButton17 = new javax.swing.JButton();
    jButton18 = new javax.swing.JButton();
    jButton19 = new javax.swing.JButton();
    jButton20 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 0, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 20, Short.MAX_VALUE)
    );

    javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
    jPanel2.setLayout(jPanel2Layout);
    jPanel2Layout.setHorizontalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 0, Short.MAX_VALUE)
    );
    jPanel2Layout.setVerticalGroup(
        jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 30, Short.MAX_VALUE)
    );

    RekenUitslag.setEditable(false);
    RekenUitslag.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N
    RekenUitslag.setHorizontalAlignment(javax.swing.JTextField.RIGHT);
    RekenUitslag.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            RekenUitslagActionPerformed(evt);
        }
    });

    jButton4.setText("7");
    jButton4.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton4ActionPerformed(evt);
        }
    });

    jButton5.setText("8");
    jButton5.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton5ActionPerformed(evt);
        }
    });

    jButton6.setText("9");
    jButton6.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton6ActionPerformed(evt);
        }
    });

    jButton7.setText("/");
    jButton7.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton7ActionPerformed(evt);
        }
    });

    jButton8.setText("6");
    jButton8.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton8ActionPerformed(evt);
        }
    });

    jButton9.setText("*");
    jButton9.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton9ActionPerformed(evt);
        }
    });

    jButton10.setText("4");
    jButton10.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton10ActionPerformed(evt);
        }
    });

    jButton11.setText("5");
    jButton11.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton11ActionPerformed(evt);
        }
    });

    jButton12.setText("3");
    jButton12.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton12ActionPerformed(evt);
        }
    });

    jButton13.setText("+");
    jButton13.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton13ActionPerformed(evt);
        }
    });

    jButton14.setText("1");
    jButton14.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton14ActionPerformed(evt);
        }
    });

    jButton15.setText("2");
    jButton15.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton15ActionPerformed(evt);
        }
    });

    jButton16.setText("=");
    jButton16.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton16ActionPerformed(evt);
        }
    });

    jButton17.setText("-");
    jButton17.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton17ActionPerformed(evt);
        }
    });

    jButton18.setText("0");
    jButton18.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton18ActionPerformed(evt);
        }
    });

    jButton19.setText("C");
    jButton19.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton19ActionPerformed(evt);
        }
    });

    jButton20.setIcon(new javax.swing.ImageIcon(getClass().getResource("/googleonlineretry.jpg"))); // NOI18N
    jButton20.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton20ActionPerformed(evt);
        }
    });

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        .addGroup(layout.createSequentialGroup()
            .addGap(35, 35, 35)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(jButton20, javax.swing.GroupLayout.PREFERRED_SIZE, 294, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jButton18, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton19, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton16, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton17, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jButton14, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton15, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton12, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(18, 18, 18)
                    .addComponent(jButton13, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jButton10, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jButton11, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jButton8, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jButton9, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                        .addComponent(RekenUitslag)
                        .addGroup(layout.createSequentialGroup()
                            .addComponent(jButton4, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(18, 18, 18)
                            .addComponent(jButton5, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(18, 18, 18)
                            .addComponent(jButton6, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGap(18, 18, 18)
                            .addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)))))
            .addContainerGap(34, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(18, 18, 18)
            .addComponent(RekenUitslag, javax.swing.GroupLayout.PREFERRED_SIZE, 45, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(32, 32, 32)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton4, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton5, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton6, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton10, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton11, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton8, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton9, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton14, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton15, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton12, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton13, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton18, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton19, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton16, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jButton17, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addComponent(jButton20, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
    );

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

private void RekenUitslagActionPerformed(java.awt.event.ActionEvent evt) {                                             
    // TODO add your handling code here:
}                                            

private void jButton14ActionPerformed(java.awt.event.ActionEvent evt) {                                          
 String ingevuld =   RekenUitslag.getText() + jButton14.getText ();
    RekenUitslag.setText(ingevuld);
}                                         

private void jButton18ActionPerformed(java.awt.event.ActionEvent evt) {                                          
    String ingevuld =   RekenUitslag.getText() + jButton18.getText();
    RekenUitslag.setText(ingevuld);
}                                         

private void jButton13ActionPerformed(java.awt.event.ActionEvent evt) {                                          

   eersteNummer = Integer.parseInt(RekenUitslag.getText());
    RekenUitslag.setText("");
     Operator = "+";
}                                         

private void jButton15ActionPerformed(java.awt.event.ActionEvent evt) {                                          
  String ingevuld =   RekenUitslag.getText() + jButton15.getText();
    RekenUitslag.setText(ingevuld);
}                                         

private void jButton12ActionPerformed(java.awt.event.ActionEvent evt) {                                          
   String ingevuld =   RekenUitslag.getText() + jButton12.getText();
    RekenUitslag.setText(ingevuld);
}                                         

private void jButton8ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String ingevuld =   RekenUitslag.getText() + jButton8.getText();
    RekenUitslag.setText(ingevuld);
}                                        

private void jButton11ActionPerformed(java.awt.event.ActionEvent evt) {                                          
   String ingevuld =   RekenUitslag.getText() + jButton11.getText();
    RekenUitslag.setText(ingevuld);



}                                         

private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {

RekenUitslag.setText（RekenUitslag.getText（）“4”）;

}                                         

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String ingevuld =   RekenUitslag.getText() + jButton4.getText();
    RekenUitslag.setText(ingevuld);
}                                        

private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {                                         
   String ingevuld =   RekenUitslag.getText() + "8";
    RekenUitslag.setText(ingevuld);
}                                        

private void jButton6ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String ingevuld =   RekenUitslag.getText() + jButton6.getText();
    RekenUitslag.setText(ingevuld);
}                                        

private void jButton7ActionPerformed(java.awt.event.ActionEvent evt) {                                         
     eersteNummer = Integer.parseInt(RekenUitslag.getText());
    RekenUitslag.setText("");
     Operator = "/";
}                                        

private void jButton9ActionPerformed(java.awt.event.ActionEvent evt) {                                         
     Operator = "*";
    eersteNummer = Integer.parseInt(RekenUitslag.getText());
    RekenUitslag.setText( "");
}                                        

private void jButton17ActionPerformed(java.awt.event.ActionEvent evt) {                                          
    Operator = "-";
    eersteNummer = Integer.parseInt(RekenUitslag.getText());
    RekenUitslag.setText("" ) ;
}                                         

private void jButton19ActionPerformed(java.awt.event.ActionEvent evt) {                                          
    String ingevuld = RekenUitslag.getText() + jButton19.getText();
    RekenUitslag.setText("");

}                                         

private void jButton16ActionPerformed(java.awt.event.ActionEvent evt) {                                          

  /*
    String enterstring1 = RekenUitslag.getText();
   int eersteNummer = Integer.parseInt(enterstring1);
    String enterstring2 = RekenUitslag.getText();
    int  tweedeNummer = Integer.parseInt(enterstring2);
    int resultaat = eersteNummer + tweedeNummer;
   RekenUitslag.setText("" + resultaat);
    RekenUitslag.getText() ;
    RekenUitslag.setText(RekenUitslag.getText() + "=");


 */  
  String antwoord;
    tweedeNummer = Integer.parseInt(RekenUitslag.getText());
    RekenUitslag.setText("test");
  if (Operator == "+") {
      resultaat = eersteNummer + tweedeNummer;
     // antwoord = String.format("%.f", resultaat);
      RekenUitslag.setText(String.valueOf(resultaat));

    }
  else if (Operator == "-") {
   resultaat = eersteNummer - tweedeNummer;   
  RekenUitslag.setText(String.valueOf(resultaat));
  }
  else if (Operator == "*") {
   resultaat = eersteNummer * tweedeNummer;   
   RekenUitslag.setText(String.valueOf(resultaat));


  }

  else if (Operator == "/") {
    resultaat = eersteNummer / tweedeNummer;   
    RekenUitslag.setText(String.valueOf(  resultaat));

  }
    /* switch(calculation){
        case "+":
          // resultaat = firstNumer + secondNumer;
          // antwoord = String.format("%.0f", resultaat);
                  // RekenUitslag.setText(antwoord);
                   break;
             case "-":
            resultaat = eersteNummer - Double.parseDouble(RekenUitslag.getText());
            RekenUitslag.setText(Double.toString(antwoord) + "=");
            break;

             case "/":
            resultaat = eersteNummer / Double.parseDouble(RekenUitslag.getText());
            RekenUitslag.setText(Double.toString(resultaat));
            break;

             case "*":
            resultaat = eersteNummer * Double.parseDouble(RekenUitslag.getText());
            RekenUitslag.setText(Double.toString(resultaat));
            break;

             case "=":
                 resultaat = eersteNummer + Double.parseDouble(RekenUitslag.getText());
                 RekenUitslag.setText(Double.toString(resultaat));
                break; 

             default:
                 RekenUitslag.setText("=");
 }
    */
}

Pickone扩展RekenMachine {

private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {                                          
       Desktop browser = Desktop.getDesktop();
    try {
   browser.browse(new URI("http://google.com"));

   }
  catch(IOException err) {
  }

   catch (URISyntaxException err) {
   }

}
}
java swing

1 回答

  • 0

    这是一种解决方法，但不能保证满足您的需求 .

    1：创建 Pickone 类以及方法 jButton20ActionPerformed static

    static class Pickone extends Test {

    public static void jButton20ActionPerformed() {
        Desktop browser = Desktop.getDesktop();
        try {
            browser.browse(new URI("http://google.com"));

        } catch (IOException err) {
        }

        catch (URISyntaxException err) {
        }

    }
}

    2：从方法调用中删除 ActionEvent

    3：对你的 Pickone 类进行静态调用，如下所示：

    jButton20.addActionListener(new java.awt.event.ActionListener() {
    public void actionPerformed(java.awt.event.ActionEvent evt) {
        Pickone.jButton20ActionPerformed();
    }
});

    这基本上是以一种非常简单的方式解决你的问题，即使它不是你所需要的（甚至可能不是最好的方法） . 随意询问您是否需要澄清 .

    你也应该开始使用 imports ，这样你就不必每次都写出完整的包名 . javax.swing.JButton() 与进口成为 JButton() . 它们适用于每个类，大多数IDE都可以选择导入所需的所有类

    回复于

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