Question

点击提交按钮后，我的帐号（使用jtextfield）必须自动递增1。我需要像B3001，B3002等格式的sequtenial值....请帮助我帮助我

public static class SequentialNumber
{
       private static int currentNumber=3000;
       public static String GetNextNumber()
       {
            currentNumber++;
            return "B"+currentNumber;
       }
}
public Printbill() {


    contentPane1 = new JPanel();
    contentPane1.setBackground(Color.WHITE);
    contentPane1.setBorder(new EmptyBorder(5, 5, 5, 5));

    contentPane1.setLayout(null);



    dcfield = new JTextField();

    dcfield.setBounds(553, 109, 86, 20);
    contentPane1.add(dcfield);
    dcfield.setColumns(10);
    String ContractNo=SequentialNumber.GetNextNumber();
    dcfield.setText(ContractNo);
    JButton btnAdd = new JButton("ADD");
    btnAdd.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
          Printbill p=new Printbill();
          dispose();
            p.setVisible(true);
            SequentialNumber s=new SequentialNumber();
            String stt=s.GetNextNumber();
           dcfield.setText(stt);
        }
    });

 }
}

Answer 1

这是工作代码

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.border.EmptyBorder;

public class Printbill extends JFrame {
    public static class SequentialNumber {
        private static int currentNumber = 3000;

        public static String GetNextNumber() {
            currentNumber++;
            return "B" + currentNumber;
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new Printbill();
            }
        });
    }

    public Printbill() {

        JPanel contentPane1 = new JPanel();
        contentPane1.setBackground(Color.WHITE);
        contentPane1.setBorder(new EmptyBorder(5, 5, 5, 5));

        contentPane1.setLayout(new BorderLayout(5, 5));

        final JTextField dcfield = new JTextField();

        contentPane1.add(dcfield);
        dcfield.setColumns(10);
        String contractNo = SequentialNumber.GetNextNumber();
        dcfield.setText(contractNo);
        JButton btnAdd = new JButton("ADD");
        contentPane1.add(btnAdd, BorderLayout.EAST);
        getContentPane().add(contentPane1);
        btnAdd.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                String stt = SequentialNumber.GetNextNumber();
                dcfield.setText(stt);
            }
        });
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setVisible(true);

    }
}

您的代码出了什么问题：

您尝试使用绝对布局（setLayout(null)）。这是不好的做法，所以我将布局更改为BorderLayout。之后我添加了pack()来为窗口设置合适的大小（此方法仅适用于非空布局）。有关详细信息，请参阅here。
我已更改动作侦听器，因此它只更新文本字段。
SwingUtilities.invokeLater。必须在事件调度程序线程（EDT）中执行所有窗口小部件初始化/操作。 SwingUtilities.invokeLater允许在EDT中调用一段代码。

当点击添加按钮时，jtextfield从B3001开始递增1

1 个答案: