Java : Wait for user input on swing window

Question

这个问题已经有答案了:

Swing GUI doesn't wait for user input (2 个回答)

已关闭 7 年前。

所以，我大约一周前开始学习 Java，我正在构建一个小程序，用于一般性地使用 swing 和 oop/java 进行训练，但遇到了一些问题。

该程序(到目前为止)有一个 MainClass 和一个 Window 类。MainClass 创建 Window 类的实例，该实例创建 JFrame 并将用户输入保存在字段中。

此时，MainClass 打印输出，这是我通过 getters 方法获得的。

问题是我仍然以程序的方式思考:MainClass 打印 null，因为它不等待窗口的 istance 来获取用户输入。

如何修复它，从而让 main 在打印之前等待窗口的距离接受用户输入？

铌。 Jframe 的东西工作了，窗口出现了，只是 MainClass 没有等待它做它应该做的事情。我可以(我认为？)使用一些 sleep 命令来等待，但这似乎完全错误。

这是MainClass.java的代码

import java.util.Arrays;

public class MainClass {

    private char[] password;
    private String pin;

    public static void main(String[] args) {

        Window w = new Window();    
        System.out.println(w.getPin() + Arrays.toString(w.getPassword()) + '1');
    }


}

和Window.java

import java.awt.*;
import javax.swing.*;
import java.awt.Window.Type;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;

import net.miginfocom.swing.MigLayout;


public class Window extends JFrame{

    private JTextField textField_1;
    private JButton btnNewButton;
    private JPanel panel;
    private JPasswordField passwordField;
    private char[] password = new char[10];
    private String pin;


    public Window() {

        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);
        this.setSize(370, 150);
        this.setForeground(new Color(192, 192, 192));
        this.setTitle("Access Password Manager");
        this.setResizable(false);

        panel = new JPanel();
        getContentPane().add(panel, BorderLayout.CENTER);
        panel.setLayout(new MigLayout("", "[70.00][132.00,grow][44.00][67.00,grow][61.00][]", "[19.00][34.00][]"));

        JLabel lblNewLabel = new JLabel("Password");
        panel.add(lblNewLabel, "cell 0 1,alignx trailing,aligny center");

        passwordField = new JPasswordField();
        passwordField.setColumns(13);
        panel.add(passwordField, "cell 1 1,alignx center");

        JLabel lblNewLabel_1 = new JLabel("Key");
        panel.add(lblNewLabel_1, "cell 2 1,alignx center,aligny center");

        textField_1 = new JTextField();
        panel.add(textField_1, "cell 3 1,alignx left,aligny center");
        textField_1.setColumns(4);

        btnNewButton = new JButton("Log In");
        ListenForButton listener = new ListenForButton();

        btnNewButton.addActionListener(listener);
        panel.add(btnNewButton, "cell 4 1");

        this.setVisible(true);

    }

        private class ListenForButton implements ActionListener{


            @Override
            public void actionPerformed(ActionEvent e) {

                if(e.getSource() == btnNewButton){

                    if (passwordField.getPassword().length < 10){

                        password = passwordField.getPassword().clone();   
                    }

                    pin = textField_1.getText();

                }
            }       
        }


        public char[] getPassword(){            
            return password;            
        }

        public String getPin(){
            return pin;     
        }


}

编辑:

这不仅仅是打印，我知道我可以直接在 Window.class 中进行打印。如果我解释得不好，我很抱歉。请将 println 视为“一旦窗口从输入中保存了这些字段，我就需要访问和处理这些字段”。

Answer 1

您可以使用模式对话框来获取用户输入，该对话框将在其可见时阻止代码执行，并在其不可见时继续执行(这很神奇)，看看 How to Make Dialogs了解更多详情

已更新

模式对话框只会阻止事件调度线程(从技术上讲，它不会阻止它，它只是绕过它)，请参阅Initial Threads了解更多详情

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import net.miginfocom.swing.MigLayout;

public class MainClass {

    private char[] password;
    private String pin;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                System.out.println("Before Window");
                Window w = new Window();
                System.out.println("After Window");
                System.out.println(w.getPin() + Arrays.toString(w.getPassword()) + '1');
            }
        });
    }

    public static class Window extends JDialog {

        private JTextField textField_1;
        private JButton btnNewButton;
        private JPanel panel;
        private JPasswordField passwordField;
        private char[] password = new char[10];
        private String pin;

        public Window() {

            this.setModal(true);
            this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
            this.setLocationRelativeTo(null);
            this.setSize(370, 150);
            this.setForeground(new Color(192, 192, 192));
            this.setTitle("Access Password Manager");
            this.setResizable(false);

            panel = new JPanel();
            getContentPane().add(panel, BorderLayout.CENTER);
            panel.setLayout(new MigLayout("", "[70.00][132.00,grow][44.00][67.00,grow][61.00][]", "[19.00][34.00][]"));

            JLabel lblNewLabel = new JLabel("Password");
            panel.add(lblNewLabel, "cell 0 1,alignx trailing,aligny center");

            passwordField = new JPasswordField();
            passwordField.setColumns(13);
            panel.add(passwordField, "cell 1 1,alignx center");

            JLabel lblNewLabel_1 = new JLabel("Key");
            panel.add(lblNewLabel_1, "cell 2 1,alignx center,aligny center");

            textField_1 = new JTextField();
            panel.add(textField_1, "cell 3 1,alignx left,aligny center");
            textField_1.setColumns(4);

            btnNewButton = new JButton("Log In");
            ListenForButton listener = new ListenForButton();

            btnNewButton.addActionListener(listener);
            panel.add(btnNewButton, "cell 4 1");

            this.setVisible(true);

        }

        private class ListenForButton implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {

                if (e.getSource() == btnNewButton) {

                    if (passwordField.getPassword().length < 10) {

                        password = passwordField.getPassword().clone();
                    }

                    pin = textField_1.getText();

                }
            }
        }

        public char[] getPassword() {
            return password;
        }

        public String getPin() {
            return pin;
        }

    }
}