如何从按钮关闭的 java swing 窗口返回值?

2022-01-24 00:00:00 java swing jbutton jframe

基本上，我的主代码中有某处调用了这行代码

Basically, I have somewhere in my main code where this line of code is called

editwindow clubeditwindow = new editwindow(1,"Club Edit");

这一行打开了一个新的 JFrame，它基本上可以编辑来自主类的一堆信息.我有 2 个按钮，称为保存和取消.单击保存时，我想从文本字段中获取值，然后将其放入一个新对象并将其返回给主类，然后关闭窗口.单击取消时，我希望它不做任何事情，这很简单.

This line opens a new JFrame that can basically edit a bunch of information from the main class. I have 2 buttons called save and cancel. When save is clicked, I want to take the values from the textfields and then put it into a new object and return that to the main class, and close the window. When cancel is clicked, I want it to just not do anything, which is simple enough.

提前致谢.

推荐答案

不要将窗口显示为 JFrame，而是将其显示为模式对话框.然后在它不再可见后，主 GUI 可以查询该对象以获取它所拥有的任何信息.最简单的方法是使用 JOptionPane ——如果使用得当，它们是聪明的小野兽.

Don't display the window as a JFrame but rather display it as a modal dialog. Then after it is no longer visible, the main GUI can query the object for any information that it holds. The simplest way to do this is to use a JOptionPane -- they are clever little beasts if used correctly.

这是我的意思的一个例子.JOptionPane 包含使用 GridBagLayout 显示信息的 JPane.

Here's an example of what I mean. The JOptionPane holds JPane that displays information using a GridBagLayout.

ComplexOptionPane.java:显示主 JFrame.

ComplexOptionPane.java: displays the main JFrame.

import java.awt.event.*;
import javax.swing.*;

@SuppressWarnings("serial")
public class ComplexOptionPane extends JPanel {
   private PlayerEditorPanel playerEditorPanel = new PlayerEditorPanel();
   private JTextArea textArea = new JTextArea(20, 40);

   public ComplexOptionPane() {
      add(new JScrollPane(textArea));
      add(new JButton(new AbstractAction("Get Player Information") {

         @Override
         public void actionPerformed(ActionEvent arg0) {
            int result = JOptionPane.showConfirmDialog(null, playerEditorPanel,
                  "Edit Player", JOptionPane.OK_CANCEL_OPTION,
                  JOptionPane.PLAIN_MESSAGE);
            if (result == JOptionPane.OK_OPTION) {
               for (PlayerEditorPanel.FieldTitle fieldTitle : 
                  PlayerEditorPanel.FieldTitle.values()) {
                  textArea.append(String.format("%10s: %s%n", fieldTitle.getTitle(),
                        playerEditorPanel.getFieldText(fieldTitle)));
               }
            }
         }
      }));
   }

   private static void createAndShowGui() {
      ComplexOptionPane mainPanel = new ComplexOptionPane();

      JFrame frame = new JFrame("ComplexOptionPane");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

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

PlayerEditorPanel.java 包含 JOptionPane 中显示的 JPanel

PlayerEditorPanel.java which holds the JPanel that is displayed in a JOptionPane

import java.awt.*;
import java.util.HashMap;
import java.util.Map;
import javax.swing.*;

@SuppressWarnings("serial")
class PlayerEditorPanel extends JPanel {
   enum FieldTitle {
      NAME("Name"), SPEED("Speed"), STRENGTH("Strength");
      private String title;

      private FieldTitle(String title) {
         this.title = title;
      }

      public String getTitle() {
         return title;
      }
   };

   private static final Insets WEST_INSETS = new Insets(5, 0, 5, 5);
   private static final Insets EAST_INSETS = new Insets(5, 5, 5, 0);
   private Map<FieldTitle, JTextField> fieldMap = new HashMap<FieldTitle, JTextField>();

   public PlayerEditorPanel() {
      setLayout(new GridBagLayout());
      setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createTitledBorder("Player Editor"),
            BorderFactory.createEmptyBorder(5, 5, 5, 5)));
      GridBagConstraints gbc;
      for (int i = 0; i < FieldTitle.values().length; i++) {
         FieldTitle fieldTitle = FieldTitle.values()[i];
         gbc = createGbc(0, i);
         add(new JLabel(fieldTitle.getTitle() + ":", JLabel.LEFT), gbc);
         gbc = createGbc(1, i);
         JTextField textField = new JTextField(10);
         add(textField, gbc);

         fieldMap.put(fieldTitle, textField);
      }
   }

   private GridBagConstraints createGbc(int x, int y) {
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.gridx = x;
      gbc.gridy = y;
      gbc.gridwidth = 1;
      gbc.gridheight = 1;

      gbc.anchor = (x == 0) ? GridBagConstraints.WEST : GridBagConstraints.EAST;
      gbc.fill = (x == 0) ? GridBagConstraints.BOTH
            : GridBagConstraints.HORIZONTAL;

      gbc.insets = (x == 0) ? WEST_INSETS : EAST_INSETS;
      gbc.weightx = (x == 0) ? 0.1 : 1.0;
      gbc.weighty = 1.0;
      return gbc;
   }

   public String getFieldText(FieldTitle fieldTitle) {
      return fieldMap.get(fieldTitle).getText();
   }

}

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