표시 값 내가 프로젝트 그러나 문제에서 작업하고 JComboBox에

Question

안녕하세요 친구를 선택 JComboBox에 발생합니다. 그러나 문제는 단 하나의 딜러 이름이 JComboBox에있는 것입니다. 도와주세요 !. 당신은

textfield.setText(textfield.getText() + "\n" +CAmt) 

처럼 각 값을 추가하기 위해 현재의 값을 복구 할 수 있습니다 구성 요소에서 설정할 값을 연결할 필요하지만 더 나은입니다

import java.awt.EventQueue; 

import javax.swing.JFrame; 
import javax.swing.GroupLayout; 
import javax.swing.GroupLayout.Alignment; 
import javax.swing.JLabel; 
import java.awt.Font; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 

import javax.swing.JComboBox; 
import javax.swing.LayoutStyle.ComponentPlacement; 
import javax.swing.JTextField; 
import java.awt.event.ActionListener; 
import java.awt.event.ActionEvent; 

public class Demo2 { 

    private JFrame frmDemo; 
    private JTextField textField; 
    private static Connection con; 
    private String query,CAmt; 
    private PreparedStatement PStat; 
    private ResultSet res; 
    private JComboBox comboBox; 

    /** 
    * Launch the application. 
    */ 
    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      public void run() { 
       try { 
        Demo2 window = new Demo2(); 
        window.frmDemo.setVisible(true); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
     }); 
    } 

    /** 
    * Create the application. 
    */ 
    public Demo2() { 
     initialize(); 
     Database(); 
     Dealer(); 
    } 

    //********* Database ************// 
    /* CREATE TABLE Dealer (
      DealerName VARCHAR (45), 
      CreditAmount DOUBLE (10, 4) 
     );*/ 
    //************************************ 

    public static Connection Database() { 
     try 
     { 
      Class.forName("org.sqlite.JDBC"); 
      con=DriverManager.getConnection("jdbc:sqlite:C:\\Users\\Azaz\\workspace\\SalesDesk\\Database\\SalesDesk.db"); 
      return con; 
     } 
     catch(Exception e) 
     { 
      e.printStackTrace(); 
      return null; 
     } 
    } 

    public void Dealer() 
    { 
     try 
     { 
      query="Select DealerName from Dealer"; 
      PStat=con.prepareStatement(query); 
      res=PStat.executeQuery(); 
      while(res.next()) 
      { 
       String dealer=res.getString("DealerName"); 
       comboBox.addItem(dealer); 
      } 
     } 
     catch(Exception e) 
     { 
      e.printStackTrace(); 
     } 
     finally 
     { 
      try 
      { 
       PStat.close(); 
       res.close(); 
      } 
      catch(Exception e) 
      { 
       e.printStackTrace(); 
      } 
     } 
    } 

    /** 
    * Initialize the contents of the frame. 
    */ 
    private void initialize() { 
     frmDemo = new JFrame(); 
     frmDemo.setTitle("Demo"); 
     frmDemo.setBounds(100, 100, 450, 300); 
     frmDemo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

     JLabel lblNewLabel = new JLabel("Dealer"); 
     lblNewLabel.setFont(new Font("Tahoma", Font.BOLD, 11)); 

     comboBox = new JComboBox(); 
     comboBox.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent arg0) { 
       try 
       { 
        query="Select CreditAmount from Dealer Where DealerName=? "; 
        PStat=con.prepareStatement(query); 
        PStat.setString(1, comboBox.getSelectedItem().toString()); 
        res=PStat.executeQuery(); 
        while(res.next()) 
        { 
         double cdt=res.getDouble("CreditAmount"); 
         CAmt=Double.toString(cdt); 
         textField.setText(CAmt); 
        } 
       } 
       catch(Exception e) 
       { 
        e.printStackTrace(); 
       } 
       finally 
       { 
        try 
        { 
         PStat.close(); 
         res.close(); 
        } 
        catch(Exception e) 
        { 
         e.printStackTrace(); 
        } 
       } 
      } 
     }); 

     textField = new JTextField(); 
     textField.setColumns(10); 

     JLabel lblCreditAmount = new JLabel("Credit Amount"); 
     lblCreditAmount.setFont(new Font("Tahoma", Font.BOLD, 11)); 
     GroupLayout groupLayout = new GroupLayout(frmDemo.getContentPane()); 
     groupLayout.setHorizontalGroup(
      groupLayout.createParallelGroup(Alignment.LEADING) 
       .addGroup(groupLayout.createSequentialGroup() 
        .addGroup(groupLayout.createParallelGroup(Alignment.LEADING) 
         .addGroup(groupLayout.createSequentialGroup() 
          .addGap(44) 
          .addComponent(lblNewLabel, GroupLayout.PREFERRED_SIZE, 51, GroupLayout.PREFERRED_SIZE)) 
         .addGroup(groupLayout.createSequentialGroup() 
          .addContainerGap() 
          .addComponent(lblCreditAmount))) 
        .addPreferredGap(ComponentPlacement.RELATED) 
        .addGroup(groupLayout.createParallelGroup(Alignment.LEADING) 
         .addComponent(textField, GroupLayout.PREFERRED_SIZE, 182, GroupLayout.PREFERRED_SIZE) 
         .addComponent(comboBox, GroupLayout.PREFERRED_SIZE, 314, GroupLayout.PREFERRED_SIZE)) 
        .addGap(21)) 
     ); 
     groupLayout.setVerticalGroup(
      groupLayout.createParallelGroup(Alignment.LEADING) 
       .addGroup(groupLayout.createSequentialGroup() 
        .addGap(52) 
        .addGroup(groupLayout.createParallelGroup(Alignment.BASELINE) 
         .addComponent(lblNewLabel) 
         .addComponent(comboBox, GroupLayout.PREFERRED_SIZE, 29, GroupLayout.PREFERRED_SIZE)) 
        .addGap(37) 
        .addGroup(groupLayout.createParallelGroup(Alignment.BASELINE) 
         .addComponent(textField, GroupLayout.PREFERRED_SIZE, 30, GroupLayout.PREFERRED_SIZE) 
         .addComponent(lblCreditAmount)) 
        .addContainerGap(114, Short.MAX_VALUE)) 
     ); 
     frmDemo.getContentPane().setLayout(groupLayout); 
    } 
} 

Answer 1

: 여기 내 소스 코드입니다 StringBuilder을 사용하여 값을 연결 한 다음 textfield에 String으로 설정하십시오.

StringBuilder sb = new StringBuilder(); 
while(res.next()) 
{ 
    double cdt=res.getDouble("CreditAmount"); 
    CAmt=Double.toString(cdt); 
    sb.append(CAmt).append("\n"); 
} 
textField.setText(sb.toString();