我的问题是，当我按下清除按钮，它只是清除文本字段，而不是以前的数字按下的数据

Question

这里的任务是编写一个类似于pincode进程的Java程序。我只是在清除过程中遇到了一个问题因为当我按下清除按钮时，它实际上清除了文本字段但当我按下新数字时，我之前输入的数字即使在按下清除按钮之后仍然显示

enter code here
import java.awt.BorderLayout; 
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.*;
public class Pincode extends JPanel implements ActionListener {
JLabel display, displayExtra;
JButton numButton;
JButton clr;
JButton etr;
String displayContent = "";
String[] numPadContent = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "CLEAR", "0", "ENTER"};
ArrayList<JButton> buttonList;
String PASSWORD = "061904";
Pincode(Container pane) {
pane.setPreferredSize(new Dimension(320, 335));
display = new JLabel(displayContent);
displayExtra = new JLabel(displayContent);
display.setPreferredSize(new Dimension(320, 25));
display.setBorder(BorderFactory.createLoweredBevelBorder());
pane.add(display, BorderLayout.PAGE_START);
buttonList = new ArrayList<JButton>(12);
JPanel numberPanel = new JPanel();
numberPanel.setLayout(new GridLayout(4, 3, 0, 0));
numberPanel.setPreferredSize(new Dimension(320, 260));
for (int i = 0; i < numPadContent.length; i++) {
numButton = new JButton(numPadContent[i]);
buttonList.add(numButton);
}
for (int n = 0; n < buttonList.size(); n++) {
buttonList.get(n).addActionListener(this);
numberPanel.add(buttonList.get(n));
}
pane.add(numberPanel, BorderLayout.LINE_END);
clr = new JButton("Clear");
clr.setPreferredSize(new Dimension(160, 30));
clr.addActionListener(this);
etr = new JButton("Enter");
etr.setPreferredSize(new Dimension(160, 30));
etr.addActionListener(this);
pane.add(clr);
pane.add(etr);
}
public void Authorized(){
JOptionPane.showMessageDialog(null,"You are authorized");
}
public void Unauthorized(){
JOptionPane.showMessageDialog(null,"You are not authorized!!!");
}
public void actionPerformed(ActionEvent e) {
String textThere = display.getText(), textThereExtra = displayExtra.getText();
String additionalText = "";
for (int a = 0; a < buttonList.size(); a++) {
if (e.getSource().equals(buttonList.get(a)) && a!=11 && a!=9) {
additionalText = buttonList.get(a).getText();
}
}
int flag = 0;
if (e.getSource().equals(buttonList.get(9))) {
textThere = "";
textThereExtra = "";
flag = 1;
}
if(flag != 1) {
display.setText(textThere.concat("*"));
displayExtra.setText(textThereExtra.concat(additionalText));
}
else
display.setText(textThere);
if (e.getSource().equals(buttonList.get(11))) {
System.out.println(textThereExtra);
System.out.println(textThere);
if(textThereExtra.equals(PASSWORD)) {
Authorized();
}
else {
Unauthorized();
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Pincode(frame));
frame.pack();
frame.setVisible(true);
}
}

请帮助我的代码。非常感谢!

Answer 1

您只是忘记为displayExtra更新JLabel文本。只要在else块中添加displayExtra.setText(textThereExtra);，你问如果flag != 1，你应该很好去!