如果所需的项目被勾选或未被勾选，我试图提供一个弹出式 JOptionPane MessageDialog 但我没有得到任何东西。基本上，我使用 Action 监听器检查按下了哪个按钮，然后检查在上一个窗口中选择了哪个用户。如果不允许用户，那么它应该显示一个弹出消息对话框告诉他们，否则它应该检查是否在 JCheckBox 中勾选了所需的项目，如果勾选了正确的项目，它应该显示一个消息对话框“欢迎”他们进入房间。
这些类是很久以前制作的，我知道我应该更好地命名它们以及我的变量。这是一个我从未完成的相当古老的项目，所以我的编程方式存在很多缺陷，所以请不要就此批评我，尽管欢迎提供提示。
虽然我说这是一个老项目，但我仍然不擅长 Java，而且我仍在学习，所以我的代码显然并不完美。
有些名字和信息是用南非荷兰语写的，所以如果有什么不明白的就尽管问，我会为你改的。
我不太明白如何使用网站的代码高亮显示，希望我做对了，抱歉。
主类:
import javax.swing.JFrame;
public class main {
public static void main(String args[]){
window1 w1Ob = new window1();
w1Ob.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
w1Ob.setSize(250,250);
w1Ob.setVisible(true);
w1Ob.setLocationRelativeTo(null);
w1Ob.setResizable(true);
}
}
第一个窗口类:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
//has to extend JFrame to use content from JFrame, cannot import to here but can to main class, not sure how it
//works
public class window1 extends JFrame{
//creating window2 object to run window2 if inserted password is correct
window2 wO2 = new window2();
//adds needed variables
//adds jlist which is the used list
private JList list;
//names used in the jlist, jlist uses string array
private static String[] usernames = {"Jannie", "Heloise", "Juan", "Chane"};
//font used to make text larger
Font font = new Font("Sans-Serif", Font.BOLD, 24);
//attempt at making a password array that stores all the passwords as strings then is used in an if statement
//to check if correct
private static int[] passwords = {1, 2, 3, 4};
//creating variable to know which user is logged in
public int loggedUser;
//constructor to create the window
public window1(){
//title
super("Project");
//the layout used, FlowLayout, most basic layout as temporary solution until learning new one
setLayout(new FlowLayout());
//tells the jlist to use the usernames string array to display in the list, meaning it will display
//Jannie on list 1, Heloise on line 2, etc.
list = new JList(usernames);
//tells the jlist how many lines to display, if array contains > 4 strings and is told to display only
//4 it will give a scroll bar
list.setVisibleRowCount(4);
//makes sure only 1 item in the list is selected
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
//sets the jlist lists' font to preset font in variable at the top of the class
list.setFont(font);
//adds the jlist to the screen
add(new JScrollPane(list));
//adds the listener to wait for the user to select an item in the list, thus "ListSelection"
list.addListSelectionListener(
//anonymous class insides parameters for adding the listener to list
new ListSelectionListener(){
//obligatory overwrite, parameters of "ListSelectionEvent event" obligatory, not sure what
//it does...
public void valueChanged(ListSelectionEvent event){
//creating the OptionPane for the password
String pass = JOptionPane.showInputDialog(null, "Enter Password");
//converts pass to string under variable name i
int i = Integer.parseInt(pass);
//checks if entered value is equal to the value in the array, example, Jannie = list[0]
//because it's the first value in array list and 1 = pass[0] since it's the first value
//in array passwords, thus if 1 is entered it will be correct because it's the
//corresponding value in the arrays
if(i == passwords[list.getSelectedIndex()]){
int selectedValue = list.getSelectedIndex();
if(selectedValue == 0){
loggedUser = 1;
}
else if(selectedValue == 1){
loggedUser = 2;
}
else if(selectedValue == 2){
loggedUser = 3;
}
else if(selectedValue == 3){
loggedUser = 4;
}
wO2.setDefaultCloseOperation(EXIT_ON_CLOSE);
wO2.setSize(500, 500);
wO2.setVisible(true);
wO2.setLocationRelativeTo(null);
wO2.setResizable(true);
}
}
}
);
}
}
第二个窗口类:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class window2 extends JFrame{
//adding JButton variables for each button on the screen
private JButton garage;
private JButton kombuis;
private JButton badkamer;
private JButton mancave;
//adding JCheckBox variables for each required item
public JCheckBox sleutel;
public JCheckBox helmet;
public JCheckBox voorskoot;
public JCheckBox beker;
public JCheckBox handdoek;
public JCheckBox seep;
public JCheckBox musiek;
//adding String variable to tell the user what he requires to enter the area he wants
private String youNeed;
private JButton button;
public window2(){
//title
super("Access");
//3 rows (int), 4 columns (int), 15 px horizontal gap (int), 15 px vertical gap (int)
setLayout(new GridLayout(3, 4, 2, 5));
//gives parameters for garage, puts text "Garage" on the button
garage = new JButton("Garage");
//adds garage JButton to the screen
add(garage);
//gives parameters for kombuis, puts text "Kombuis" on the button
kombuis = new JButton("Kombuis");
//adds kombuis JButton to the screen
add(kombuis);
//gives parameters for badkamer, puts text "Badkamer" on the button
badkamer = new JButton("Badkamer");
//adds badkamer JButton to the screen
add(badkamer);
//gives parameters for mancave, puts text "Mancave" on the button
mancave = new JButton("Mancave");
//adds mancave JButton to the screen
add(mancave);
sleutel = new JCheckBox("Sleutel");
add(sleutel);
helmet = new JCheckBox("Helmet");
add(helmet);
voorskoot = new JCheckBox("Voorskoot");
add(voorskoot);
beker = new JCheckBox("Beker");
add(beker);
handdoek = new JCheckBox("Handdoek");
add(handdoek);
seep = new JCheckBox("Seep");
add(seep);
musiek = new JCheckBox("Musiek");
add(musiek);
HandlerClass handler = new HandlerClass();
//adds action listeners for following button to wait for user to select one
garage.addActionListener(handler);
kombuis.addActionListener(handler);
badkamer.addActionListener(handler);
mancave.addActionListener(handler);
}
private class HandlerClass implements ActionListener{
public void actionPerformed(ActionEvent event){
//create window1 object to use loggedUser variable from window1
window1 wo1 = new window1();
//create variable using window1 object to use loggedUser variable in window2 class
int loggedU = wo1.loggedUser;
if(event.getActionCommand().equals(garage)){
if(loggedU == 1){
if(sleutel.isSelected() && helmet.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the garage, Jannie");
}
else{
if(sleutel.isSelected()){
youNeed = "Helmet";
}
else if(helmet.isSelected()){
youNeed = "Sleutel";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else if(loggedU == 3){
if(sleutel.isSelected() && helmet.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the garage, Juan");
}
else{
if(sleutel.isSelected()){
youNeed = "Helmet";
}
else if(helmet.isSelected()){
youNeed = "Sleutel";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else{
JOptionPane.showMessageDialog(null, "You're not allowed in here");
}
}
if(event.getActionCommand().equals(badkamer)){
if(loggedU == 1){
if(handdoek.isSelected() && seep.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the bathroom, Jannie");
}
else{
if(handdoek.isSelected()){
youNeed = "Seep";
}
else if(seep.isSelected()){
youNeed = "Handdoek";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else if(loggedU == 2){
if(handdoek.isSelected() && seep.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the bathroom, Heloise");
}
else{
if(handdoek.isSelected()){
youNeed = "Seep";
}
else if(seep.isSelected()){
youNeed = "Handdoek";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else if(loggedU == 3){
if(handdoek.isSelected() && seep.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the bathroom, Juan");
}
else{
if(handdoek.isSelected()){
youNeed = "Seep";
}
else if(seep.isSelected()){
youNeed = "Handdoek";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else if(loggedU == 4){
if(handdoek.isSelected() && seep.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the bathroom, Chane");
}
else{
if(handdoek.isSelected()){
youNeed = "Seep";
}
else if(seep.isSelected()){
youNeed = "Handdoek";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
}
if(event.getActionCommand().equals(kombuis)){
if(loggedU == 2){
if(voorskoot.isSelected() && beker.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the kombuis, Heloise");
}
else{
if(voorskoot.isSelected()){
youNeed = "beker";
}
else if(beker.isSelected()){
youNeed = "voorskoot";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else if(loggedU == 4){
if(voorskoot.isSelected() && beker.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the kombuis, Chane");
}
else{
if(voorskoot.isSelected()){
youNeed = "beker";
}
else if(beker.isSelected()){
youNeed = "voorskoot";
}
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else{
JOptionPane.showMessageDialog(null, "You're not allowed in here");
}
}
if(event.getActionCommand().equals(mancave)){
if(loggedU == 1){
if(musiek.isSelected()){
JOptionPane.showMessageDialog(null, "Welcome to the mancave, Jannie");
}
else{
youNeed = "musiek";
JOptionPane.showMessageDialog(null, "You do not have the required items, you need: " + youNeed);
}
}
else{
JOptionPane.showMessageDialog(null, "You're not allowed in here");
}
}
}
}
}
在此先感谢您尝试解决/解决方案。
最佳答案
关于这段代码:
private class HandlerClass implements ActionListener {
public void actionPerformed(ActionEvent event) {
window1 wo1 = new window1(); // ***** problem is here *****
int loggedU = wo1.loggedUser;
if (event.getActionCommand().equals(garage)) {
出于调试目的，我已更改为:
private class HandlerClass implements ActionListener {
public void actionPerformed(ActionEvent event) {
window1 wo1 = new window1(); // ***** problem is here *****
int loggedU = wo1.loggedUser;
System.out.println("action command: " + event.getActionCommand()); //!!
System.out.println("loggedU: " + loggedU);
if (event.getActionCommand().equals(garage)) {
您会看到 loggedU 总是返回 0。
您的问题是一个常见的新手错误——您正在创建一个新的 window1 对象 w02，并假设它的状态与先前创建的 window1 对象相同，而这不是 Java 的工作方式。要获取原始 window1 对象的状态，您需要测试它，而不是新的不同实例。
例如，
import java.awt.Dialog.ModalityType;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.Window;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class MyTest {
private static void createAndShowGui() {
MainGuiPanel mainGuiPanel = new MainGuiPanel();
final JFrame frame = new JFrame("MyTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainGuiPanel);
frame.pack();
frame.setLocationRelativeTo(null);
// frame.setVisible(true);
DialogPanel dialogPanel = new DialogPanel();
JDialog dialog = new JDialog(frame, "Select User", ModalityType.APPLICATION_MODAL);
dialog.add(dialogPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
// show modal dialog
dialog.setVisible(true);
// here dialog is no longer visible
// extract datat from dialog's dialogPanel
String selectedUser = dialogPanel.getSelectedName();
// put into the main GUI
mainGuiPanel.setSelectedUser(selectedUser);
// now show the main GUI's JFrame
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class MainGuiPanel extends JPanel {
private static final long serialVersionUID = 1L;
private JButton doItButton = new JButton(new DoItAction("Do It!", KeyEvent.VK_D));
private String selectedUser;
public MainGuiPanel() {
add(doItButton);
}
public void setSelectedUser(String selectedUser) {
this.selectedUser = selectedUser;
}
private class DoItAction extends AbstractAction {
public DoItAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("Selected User: " + selectedUser);
}
}
}
class DialogPanel extends JPanel {
private static final long serialVersionUID = 1L;
public static final String[] USER_NAMES = { "Jannie", "Heloise", "Juan", "Chane" };
private JList<String> userList = new JList<>(USER_NAMES);
private String selectedName;
public DialogPanel() {
userList.addListSelectionListener(new UserListListener());
add(new JScrollPane(userList));
}
public String getSelectedName() {
return selectedName;
}
private class UserListListener implements ListSelectionListener {
@Override
public void valueChanged(ListSelectionEvent e) {
if (!e.getValueIsAdjusting()) {
selectedName = userList.getSelectedValue();
if (selectedName != null) {
Window win = SwingUtilities.getWindowAncestor(DialogPanel.this);
win.dispose();
}
}
}
}
}
编辑
您的代码没有考虑字符串大写!
改变:
if (event.getActionCommand().equals(garage)) {
到:
if (event.getActionCommand().equalsIgnoreCase(garage)) {
关于java - JButtons、ActionListener 和 JOptionPane，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26413260/