如何使用 Action Listener 和 Action Event 让 JButtons 在 JTextField 中打印整数？
How to get JButtons to print integers in a JTextField by using Action Listener and Action Event?
我正在尝试创建假设的 ATM GUI 界面以通过键盘输入几个数字。在用户单击任何按钮后，我无法让程序显示数字。为了节省时间，我只创建了一个按钮：
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
所以如果用户点击 'jbtOne' 说 4 次。 JTextField 应显示 1111。我的问题是按钮对代码行无响应：
addActionListener(listener)
如何让 JButton 打印 JTextField 中的整数？我以前已经让它工作了，但是在用这行代码添加了一个更用户友好的外观之后就没能让它再次工作了：
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
有人能指出我正确的方向吗？任何帮助将不胜感激！
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractButton;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JPasswordField;
public class TerminalATM extends JFrame
{
private JPanel panel;
public final JPasswordField passwordField = new JPasswordField(2);
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
};
private static final int GAP = 5;
private static final Font BTN_FONT = new Font(Font.DIALOG, Font.BOLD, 20);
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
private JTextField jtfNumber1 = new JTextField(8);//Define Number Field
public TerminalATM()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel standardPanel = createBtnPanel(STANDARD_BTN_TEXTS, "KeyPad");
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(0, 1));
buttonPanel.add(jtfNumber1, BorderLayout.NORTH);
buttonPanel.add(standardPanel, BorderLayout.SOUTH);
BtnListener listener = new BtnListener();
jbtOne.addActionListener(listener);
TextFieldHandler handler = new TextFieldHandler();
passwordField.addActionListener(handler);
add(buttonPanel, BorderLayout.LINE_START);
setSize(450, 500);
setVisible(true);
}
//Create Unique Rows of Buttons
private JPanel createBtnPanel(String[][] texts, String title) {
JPanel btnPanel = new JPanel();
int rows = texts.length;
int cols = texts[0].length;
btnPanel.setLayout(new GridLayout(rows, cols, GAP, GAP));
for (int row = 0; row < texts.length; row++) {
for (int col = 0; col < texts[row].length; col++) {
JButton btn = new JButton(texts[row][col]);
btn.setFont(BTN_FONT);
btnPanel.add(btn);
}
}
btnPanel.setBorder(BorderFactory.createTitledBorder(title));
return btnPanel;
}
private class TextFieldHandler implements ActionListener
{
@Override
public void actionPerformed(ActionEvent event)
{
String string = "";
if(event.getSource()==passwordField)
string = String.format("textField1: %s", event.getActionCommand());
}
}
/**** Create Button Listener and Action Listener ****/
class BtnListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
/* This is where we would set each button to the action event */
/* Only Button one for brevity */
int int1=0;
if(e.getSource().equals(jbtOne))
{
int1 = 1;
passwordField.setText(String.valueOf(int1));
}
}
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new TerminalATM();
}
});
}
}//EndTerminalATM
在我看来，您没有将 jbtOne 添加到可见面板。您的 createBtnPanel 方法创建自己的按钮并将它们添加到没有任何动作侦听器的面板中。
尝试更改 createBtnPanel 内循环的以下行：
for (int row = 0; row < texts.length; row++) {
for (int col = 0; col < texts[row].length; col++) {
final String text = texts[row][col];
final JButton btn = new JButton(text);
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ev) {
passwordField.setText(text);
}
});
btn.setFont(BTN_FONT);
btnPanel.add(btn);
}
}
如果您不明白它的作用或有任何问题，请告诉我。
如果您使用 Java8，此代码也可以大大简化，但我假设您不会让我的回答直截了当。
您的听众正在使用 passwordField，但您似乎已经在面板中添加了一个文本字段，可以使用 passwordField 或 jtfNumber1。
在下面的代码中，我让按钮侦听器响应并输出单击按钮的文本以显示在文本字段中。
所有更改都以 /**** 开头记录，以解释我所做的。
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package logging;
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TerminalATM extends JFrame
{
private JPanel panel;
public final JPasswordField passwordField = new JPasswordField(2);
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
};
private static final int GAP = 5;
private static final Font BTN_FONT = new Font(Font.DIALOG, Font.BOLD, 20);
/**** what is the purpose of this JButton ? */
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
private JTextField jtfNumber1 = new JTextField(8);//Define Number Field
public TerminalATM()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel standardPanel = createBtnPanel(STANDARD_BTN_TEXTS, "KeyPad");
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(0, 1));
buttonPanel.add(jtfNumber1, BorderLayout.NORTH);
buttonPanel.add(standardPanel, BorderLayout.SOUTH);
/**** The action listener should go on the button which is pressed
see createBtnPanel */
// BtnListener listener = new BtnListener();
// jbtOne.addActionListener(listener);
/**** what is the purpose of this JPasswordField ?
it is not being added to any JPanel */
TextFieldHandler handler = new TextFieldHandler();
passwordField.addActionListener(handler);
add(buttonPanel, BorderLayout.LINE_START);
setSize(450, 500);
setVisible(true);
}
//Create Unique Rows of Buttons
private JPanel createBtnPanel(String[][] texts, String title) {
JPanel btnPanel = new JPanel();
int rows = texts.length;
int cols = texts[0].length;
btnPanel.setLayout(new GridLayout(rows, cols, GAP, GAP));
/**** create the listener */
BtnListener listener = new BtnListener();
for (String[] text : texts) {
for (String element : text) {
JButton btn = new JButton(element);
btn.setFont(BTN_FONT);
/**** add the listener to each button*/
btn.addActionListener(listener);
btnPanel.add(btn);
}
}
btnPanel.setBorder(BorderFactory.createTitledBorder(title));
return btnPanel;
}
private class TextFieldHandler implements ActionListener
{
@Override
public void actionPerformed(ActionEvent event)
{
String string = "";
if(event.getSource()==passwordField) {
string = String.format("textField1: %s", event.getActionCommand());
}
}
}
/**** Create Button Listener and Action Listener ****/
class BtnListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
/* This is where we would set each button to the action event */
/* Only Button one for brevity */
/**** what is the purpose of it ? int int1=0; */
/**** the event is generated by the button created in
createBtnPanel so e.getSource() can not be equal to
jbtOne. It should be an instance of JButton */
if(e.getSource() instanceof JButton)
{
/**** get the JButton clicked */
JButton button = (JButton) e.getSource() ;
/**** display its text on the text field */
jtfNumber1.setText(button.getText());
}
}
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
/**** new MultiplePanels(); is un defined */
new TerminalATM();
}
});
}
}//EndTerminalATM
我需要更好地了解您希望通过密码字段和操作侦听器实现的功能是什么，因此如果需要，我可以尝试进一步帮助您。 (0:
我正在尝试创建假设的 ATM GUI 界面以通过键盘输入几个数字。在用户单击任何按钮后，我无法让程序显示数字。为了节省时间，我只创建了一个按钮：
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
所以如果用户点击 'jbtOne' 说 4 次。 JTextField 应显示 1111。我的问题是按钮对代码行无响应：
addActionListener(listener)
如何让 JButton 打印 JTextField 中的整数？我以前已经让它工作了，但是在用这行代码添加了一个更用户友好的外观之后就没能让它再次工作了：
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
有人能指出我正确的方向吗？任何帮助将不胜感激！
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JFrame;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractButton;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JPasswordField;
public class TerminalATM extends JFrame
{
private JPanel panel;
public final JPasswordField passwordField = new JPasswordField(2);
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
};
private static final int GAP = 5;
private static final Font BTN_FONT = new Font(Font.DIALOG, Font.BOLD, 20);
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
private JTextField jtfNumber1 = new JTextField(8);//Define Number Field
public TerminalATM()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel standardPanel = createBtnPanel(STANDARD_BTN_TEXTS, "KeyPad");
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(0, 1));
buttonPanel.add(jtfNumber1, BorderLayout.NORTH);
buttonPanel.add(standardPanel, BorderLayout.SOUTH);
BtnListener listener = new BtnListener();
jbtOne.addActionListener(listener);
TextFieldHandler handler = new TextFieldHandler();
passwordField.addActionListener(handler);
add(buttonPanel, BorderLayout.LINE_START);
setSize(450, 500);
setVisible(true);
}
//Create Unique Rows of Buttons
private JPanel createBtnPanel(String[][] texts, String title) {
JPanel btnPanel = new JPanel();
int rows = texts.length;
int cols = texts[0].length;
btnPanel.setLayout(new GridLayout(rows, cols, GAP, GAP));
for (int row = 0; row < texts.length; row++) {
for (int col = 0; col < texts[row].length; col++) {
JButton btn = new JButton(texts[row][col]);
btn.setFont(BTN_FONT);
btnPanel.add(btn);
}
}
btnPanel.setBorder(BorderFactory.createTitledBorder(title));
return btnPanel;
}
private class TextFieldHandler implements ActionListener
{
@Override
public void actionPerformed(ActionEvent event)
{
String string = "";
if(event.getSource()==passwordField)
string = String.format("textField1: %s", event.getActionCommand());
}
}
/**** Create Button Listener and Action Listener ****/
class BtnListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
/* This is where we would set each button to the action event */
/* Only Button one for brevity */
int int1=0;
if(e.getSource().equals(jbtOne))
{
int1 = 1;
passwordField.setText(String.valueOf(int1));
}
}
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new TerminalATM();
}
});
}
}//EndTerminalATM
在我看来，您没有将 jbtOne 添加到可见面板。您的 createBtnPanel 方法创建自己的按钮并将它们添加到没有任何动作侦听器的面板中。
尝试更改 createBtnPanel 内循环的以下行：
for (int row = 0; row < texts.length; row++) {
for (int col = 0; col < texts[row].length; col++) {
final String text = texts[row][col];
final JButton btn = new JButton(text);
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ev) {
passwordField.setText(text);
}
});
btn.setFont(BTN_FONT);
btnPanel.add(btn);
}
}
如果您不明白它的作用或有任何问题，请告诉我。
如果您使用 Java8，此代码也可以大大简化，但我假设您不会让我的回答直截了当。
您的听众正在使用 passwordField，但您似乎已经在面板中添加了一个文本字段，可以使用 passwordField 或 jtfNumber1。
在下面的代码中，我让按钮侦听器响应并输出单击按钮的文本以显示在文本字段中。 所有更改都以 /**** 开头记录，以解释我所做的。
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package logging;
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TerminalATM extends JFrame
{
private JPanel panel;
public final JPasswordField passwordField = new JPasswordField(2);
private static final String[][] STANDARD_BTN_TEXTS =
{
{"1", "2", "3"},
{"4", "5", "6"},
{"7", "8", "9"},
{ "0" }
};
private static final int GAP = 5;
private static final Font BTN_FONT = new Font(Font.DIALOG, Font.BOLD, 20);
/**** what is the purpose of this JButton ? */
public JButton jbtOne = new JButton(STANDARD_BTN_TEXTS[0][0]);
private JTextField jtfNumber1 = new JTextField(8);//Define Number Field
public TerminalATM()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel standardPanel = createBtnPanel(STANDARD_BTN_TEXTS, "KeyPad");
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(0, 1));
buttonPanel.add(jtfNumber1, BorderLayout.NORTH);
buttonPanel.add(standardPanel, BorderLayout.SOUTH);
/**** The action listener should go on the button which is pressed
see createBtnPanel */
// BtnListener listener = new BtnListener();
// jbtOne.addActionListener(listener);
/**** what is the purpose of this JPasswordField ?
it is not being added to any JPanel */
TextFieldHandler handler = new TextFieldHandler();
passwordField.addActionListener(handler);
add(buttonPanel, BorderLayout.LINE_START);
setSize(450, 500);
setVisible(true);
}
//Create Unique Rows of Buttons
private JPanel createBtnPanel(String[][] texts, String title) {
JPanel btnPanel = new JPanel();
int rows = texts.length;
int cols = texts[0].length;
btnPanel.setLayout(new GridLayout(rows, cols, GAP, GAP));
/**** create the listener */
BtnListener listener = new BtnListener();
for (String[] text : texts) {
for (String element : text) {
JButton btn = new JButton(element);
btn.setFont(BTN_FONT);
/**** add the listener to each button*/
btn.addActionListener(listener);
btnPanel.add(btn);
}
}
btnPanel.setBorder(BorderFactory.createTitledBorder(title));
return btnPanel;
}
private class TextFieldHandler implements ActionListener
{
@Override
public void actionPerformed(ActionEvent event)
{
String string = "";
if(event.getSource()==passwordField) {
string = String.format("textField1: %s", event.getActionCommand());
}
}
}
/**** Create Button Listener and Action Listener ****/
class BtnListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
/* This is where we would set each button to the action event */
/* Only Button one for brevity */
/**** what is the purpose of it ? int int1=0; */
/**** the event is generated by the button created in
createBtnPanel so e.getSource() can not be equal to
jbtOne. It should be an instance of JButton */
if(e.getSource() instanceof JButton)
{
/**** get the JButton clicked */
JButton button = (JButton) e.getSource() ;
/**** display its text on the text field */
jtfNumber1.setText(button.getText());
}
}
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
/**** new MultiplePanels(); is un defined */
new TerminalATM();
}
});
}
}//EndTerminalATM
我需要更好地了解您希望通过密码字段和操作侦听器实现的功能是什么，因此如果需要，我可以尝试进一步帮助您。 (0: