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  3. なぜtxtDisplay（）メソッドが見つからないのですか？

なぜtxtDisplay（）メソッドが見つからないのですか？

2016-03-21 28 views
1

私はJava電卓を作ろうとしています。私はnetbeansで自分のコードを書く。ここでなぜtxtDisplay（）メソッドが見つからないのですか？

C:\Users\Nishan\Documents\javawork\Calculator\src\Calculation\Calculation.java:215: error: cannot find symbol txtDisplay.setText(btn1Text); symbol: variable txtDisplay location: class Calculation

私のコードです：

private void btn1ActionPerformed(java.awt.event.ActionEvent evt) {          
    String btn1Text; 
    btn1Text = txtDisplay.getText() + btn1.getText(); 
txtDisplay.setText(btn1Text); 
} 



    **/* 
* 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 Calculation; 

/** 
* 
* @author Nishan 
*/ 
public class Calculation extends javax.swing.JFrame { 

    double firstnum; 
    double secondnum; 
    double result; 
    String operation; 
    public Calculation() { 
     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() { 

     jTextField1 = new javax.swing.JTextField(); 
     btn1 = new javax.swing.JButton(); 
     btn2 = new javax.swing.JButton(); 
     btn3 = new javax.swing.JButton(); 
     btn4 = new javax.swing.JButton(); 
     btn5 = new javax.swing.JButton(); 
     btn6 = new javax.swing.JButton(); 
     btn7 = new javax.swing.JButton(); 
     btn8 = new javax.swing.JButton(); 
     btn9 = new javax.swing.JButton(); 
     btn10 = new javax.swing.JButton(); 
     btn11 = new javax.swing.JButton(); 
     btn12 = new javax.swing.JButton(); 
     btn13 = new javax.swing.JButton(); 
     btn14 = new javax.swing.JButton(); 
     btn15 = new javax.swing.JButton(); 
     btn16 = new javax.swing.JButton(); 
     btn18 = new javax.swing.JButton(); 
     btn17 = new javax.swing.JButton(); 

     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 

     jTextField1.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     jTextField1.setHorizontalAlignment(javax.swing.JTextField.RIGHT); 

     btn1.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn1.setText("1"); 
     btn1.addActionListener(new java.awt.event.ActionListener() { 
      public void actionPerformed(java.awt.event.ActionEvent evt) { 
       btn1ActionPerformed(evt); 
      } 
     }); 

     btn2.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn2.setText("2"); 

     btn3.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn3.setText("3"); 

     btn4.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn4.setText("+"); 

     btn5.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn5.setText("4"); 

     btn6.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn6.setText("5"); 

     btn7.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn7.setText("6"); 

     btn8.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn8.setText("-"); 

     btn9.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn9.setText("7"); 

     btn10.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn10.setText("8"); 

     btn11.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn11.setText("9"); 

     btn12.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn12.setText("*"); 

     btn13.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn13.setText("."); 

     btn14.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn14.setText("0"); 

     btn15.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn15.setText("C"); 

     btn16.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn16.setText("/"); 

     btn18.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn18.setText("="); 

     btn17.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N 
     btn17.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() 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addComponent(jTextField1) 
        .addGroup(layout.createSequentialGroup() 
         .addComponent(btn1) 
         .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
         .addComponent(btn2) 
         .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
         .addComponent(btn3) 
         .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
         .addComponent(btn4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
        .addGroup(layout.createSequentialGroup() 
         .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false) 
          .addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup() 
           .addComponent(btn14) 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
           .addComponent(btn13, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
          .addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup() 
           .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false) 
            .addComponent(btn5, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
            .addComponent(btn9, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
           .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) 
            .addComponent(btn6, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
            .addComponent(btn10, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))) 
         .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
          .addGroup(layout.createSequentialGroup() 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
           .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) 
            .addComponent(btn7, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
            .addComponent(btn11, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
           .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
            .addComponent(btn8, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
            .addComponent(btn12, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))) 
          .addGroup(layout.createSequentialGroup() 
           .addGap(6, 6, 6) 
           .addComponent(btn15, javax.swing.GroupLayout.PREFERRED_SIZE, 45, javax.swing.GroupLayout.PREFERRED_SIZE) 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
           .addComponent(btn16, javax.swing.GroupLayout.PREFERRED_SIZE, 53, javax.swing.GroupLayout.PREFERRED_SIZE)) 
          .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup() 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
           .addComponent(btn18, javax.swing.GroupLayout.PREFERRED_SIZE, 99, javax.swing.GroupLayout.PREFERRED_SIZE))))) 
       .addContainerGap()) 
      .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(layout.createSequentialGroup() 
        .addContainerGap() 
        .addComponent(btn17, javax.swing.GroupLayout.PREFERRED_SIZE, 99, javax.swing.GroupLayout.PREFERRED_SIZE) 
        .addContainerGap(125, Short.MAX_VALUE))) 
     ); 
     layout.setVerticalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(layout.createSequentialGroup() 
       .addContainerGap() 
       .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
        .addComponent(btn1) 
        .addComponent(btn2) 
        .addComponent(btn3) 
        .addComponent(btn4)) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
        .addComponent(btn5) 
        .addComponent(btn6) 
        .addComponent(btn7) 
        .addComponent(btn8)) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
        .addComponent(btn9) 
        .addComponent(btn10) 
        .addComponent(btn11) 
        .addComponent(btn12)) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
        .addComponent(btn14) 
        .addComponent(btn13) 
        .addComponent(btn15) 
        .addComponent(btn16)) 
       .addGap(16, 16, 16) 
       .addComponent(btn18) 
       .addContainerGap(24, Short.MAX_VALUE)) 
      .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
       .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup() 
        .addContainerGap(240, Short.MAX_VALUE) 
        .addComponent(btn17) 
        .addGap(23, 23, 23))) 
     ); 

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

    private void btn1ActionPerformed(java.awt.event.ActionEvent evt) {          
     String btn1Text; 
     btn1Text = txtDisplay.getText() + btn1.getText(); 
    txtDisplay.setText(btn1Text); 
    }          

    /** 
    * @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(Calculation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (InstantiationException ex) { 
      java.util.logging.Logger.getLogger(Calculation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (IllegalAccessException ex) { 
      java.util.logging.Logger.getLogger(Calculation.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (javax.swing.UnsupportedLookAndFeelException ex) { 
      java.util.logging.Logger.getLogger(Calculation.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 Calculation().setVisible(true); 
      } 
     }); 
    } 

    // Variables declaration - do not modify      
    private javax.swing.JButton btn1; 
    private javax.swing.JButton btn10; 
    private javax.swing.JButton btn11; 
    private javax.swing.JButton btn12; 
    private javax.swing.JButton btn13; 
    private javax.swing.JButton btn14; 
    private javax.swing.JButton btn15; 
    private javax.swing.JButton btn16; 
    private javax.swing.JButton btn17; 
    private javax.swing.JButton btn18; 
    private javax.swing.JButton btn2; 
    private javax.swing.JButton btn3; 
    private javax.swing.JButton btn4; 
    private javax.swing.JButton btn5; 
    private javax.swing.JButton btn6; 
    private javax.swing.JButton btn7; 
    private javax.swing.JButton btn8; 
    private javax.swing.JButton btn9; 
    private javax.swing.JTextField jTextField1; 
    // End of variables declaration     
} 
**

出典

2016-03-21 Nishan Singha

+5

どこで 'txtDisplay'を定義しましたか？ – SomeJavaGuy

+2

[mcve]を表示してください。私の推測では、 'txtDisplay'はどこかの* local *変数として宣言されています。 –

+0

メソッド？変数のように使用しましたか？ –

答えて

0

あなたはあなたのクラスの変数txtDisplayを持っていないが、私は自分のソースコードをビルドするとき、それは私にエラーを示しています。それを追加します。 はい、それは方法ではなく、変数です。

出典

2016-03-21 08:06:33

0

まず、txtDisplayを操作するためには、まずtxtDisplayを初期化する必要があります。

どのようなディスプレイを実装しようとしていますか？

1行入力表示を実装しようとしている場合は、

  • インポートこのコードのパッケージJTextFieldはimport javax.swing.JTextArea;

  • 複数行表示を実現しようとしている場合JTextArea txtDisplay = new JTextArea();

でJTextAreaのを初期化。同じ手順に従って、JTextFieldをJTextAreaに置き換えます。

https://docs.oracle.com/javase/7/docs/api/javax/swing/JTextArea.htmlおよびhttps://docs.oracle.com/javase/7/docs/api/javax/swing/JTextField.htmlを参照してください。

出典

2016-03-21 09:31:10 Nkem

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