12.3 文本输入

1 文本输入

JPanel panel = new JPanel();JTextField textField = new JTextField("Default input", 20);panel.add(textField);

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2 标签和标签组件

JLabel label = new JLabel("User name: ", SwingConstants.RIGHT);JLabel label = new JLabel("User name: ", JLabel.RIGHT);

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3 密码域

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4 文本域

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5 滚动窗格

import java.awt.*;import javax.swing.*;/** * @version 1.41 2015-06-12 * @author Cay Horstmann */public class TextComponentTest{   public static void main(String[] args)   {      EventQueue.invokeLater(() -> {         JFrame frame = new TextComponentFrame();         frame.setTitle("TextComponentTest");         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         frame.setVisible(true);      });   }}import java.awt.BorderLayout;import java.awt.GridLayout;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JPasswordField;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.JTextField;import javax.swing.SwingConstants;/** * A frame with sample text components. */public class TextComponentFrame extends JFrame{   public static final int TEXTAREA_ROWS = 8;   public static final int TEXTAREA_COLUMNS = 20;   public TextComponentFrame()   {      JTextField textField = new JTextField();      JPasswordField passwordField = new JPasswordField();      JPanel northPanel = new JPanel();      northPanel.setLayout(new GridLayout(2, 2));      northPanel.add(new JLabel("User name: ", SwingConstants.RIGHT));      northPanel.add(textField);      northPanel.add(new JLabel("Password: ", SwingConstants.RIGHT));      northPanel.add(passwordField);      add(northPanel, BorderLayout.NORTH);      JTextArea textArea = new JTextArea(TEXTAREA_ROWS, TEXTAREA_COLUMNS);      JScrollPane scrollPane = new JScrollPane(textArea);      add(scrollPane, BorderLayout.CENTER);      // add button to append text into the text area      JPanel southPanel = new JPanel();      JButton insertButton = new JButton("Insert");      southPanel.add(insertButton);      insertButton.addActionListener(event ->         textArea.append("User name: " + textField.getText() + " Password: "            + new String(passwordField.getPassword()) + "\n"));      add(southPanel, BorderLayout.SOUTH);      pack();   }}