JScrollPane的底部被切断了

我正在尝试创建一个简单的电子邮件客户端，正在切断身体的底部。 如果我添加一个水平滚动条，它不会出现，并且垂直滚动条的底部也不会出现。

这是我的代码：

import java.awt.BorderLayout; import java.awt.Container; import java.awt.FlowLayout; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JScrollBar; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.swing.UIManager; @SuppressWarnings("serial") public class gui extends JFrame{ gui(String title, int x, int y){ super(title); setSize(x,y); setDefaultCloseOperation(EXIT_ON_CLOSE); setResizable(false); } public void addElements(){ Font size30 = new Font(null, Font.PLAIN, 30); JPanel pnl = new JPanel(); Container contentPane = getContentPane(); //--- User Info ---// JPanel userInfo = new JPanel(); JLabel userLabel = new JLabel("Username: "); JTextField userField = new JTextField(12); userInfo.add(userLabel); userInfo.add(userField); JLabel passLabel = new JLabel("Password: "); JTextField passField = new JTextField(10); userInfo.add(passLabel); userInfo.add(passField); JLabel serverLabel = new JLabel("Mail Server: "); JTextField serverField = new JTextField(10); userInfo.add(serverLabel); userInfo.add(serverField); JLabel portLabel = new JLabel("Server Port: "); JTextField portField = new JTextField(3); userInfo.add(portLabel); userInfo.add(portField); //--- To: CC: and Subject Fields ---// JPanel msgInfo = new JPanel(); JLabel toLabel = new JLabel("To: "); JTextField toField = new JTextField(30); msgInfo.add(toLabel); msgInfo.add(toField); JLabel subLabel = new JLabel("Subject: "); JTextField subField = new JTextField(30); msgInfo.add(subLabel); msgInfo.add(subField); //--- Body ---// JPanel bodyPnl = new JPanel(new BorderLayout(10,10)); JLabel bodyLabel = new JLabel("Body"); bodyLabel.setFont(size30); JTextArea bodyField = new JTextArea(30,70); bodyField.setLineWrap(true); bodyField.setWrapStyleWord(true); JScrollPane bodyScroll = new JScrollPane(bodyField); bodyScroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); bodyScroll.setBounds(getX(), getY(), bodyField.getWidth(), bodyField.getHeight()); bodyPnl.add("South",bodyScroll); pnl.add(userInfo); pnl.add(msgInfo); pnl.add(bodyLabel); pnl.add(bodyScroll); contentPane.add("North", pnl); setVisible(true); } } 

在我的主类中，我只是创建一个新的gui然后调用addElements（）函数。

Answer 1

FlowLayout没有很好地“包装”。 考虑一个不同的布局，例如GridBagLayout ……

此外，停止“尝试”强制在UI上使用大小，您无法控制影响大小调整的因素。

相反，依赖于布局管理器和APIfunction。 例如，不是在你的框架上调用setSize ，而是调用pack …我很快就会发布，但是我花了很长时间才找到那个电话……我在摸不着头脑，想知道为什么用户界面不会布局的方式我期望…

 import java.awt.Color; import java.awt.EventQueue; import java.awt.Font; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; import javax.swing.JFrame; import static javax.swing.JFrame.EXIT_ON_CLOSE; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; import javax.swing.border.LineBorder; public class Test extends JFrame { 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) { } Test frame = new Test("Testing", 400, 400); } }); } Test(String title, int x, int y) { super(title); setDefaultCloseOperation(EXIT_ON_CLOSE); addElements(); pack(); setVisible(true); // setResizable(false); } public void addElements() { Font size30 = new Font(null, Font.PLAIN, 30); //--- User Info ---// JPanel userInfo = new JPanel(new GridBagLayout()); GridBagConstraints gbc = new GridBagConstraints(); gbc.insets = new Insets(2, 2, 4, 2); gbc.gridx = 0; gbc.gridy = 0; JLabel userLabel = new JLabel("Username: "); JTextField userField = new JTextField(12); userInfo.add(userLabel, gbc); gbc.gridx++; userInfo.add(userField, gbc); JLabel passLabel = new JLabel("Password: "); JTextField passField = new JTextField(10); gbc.gridx++; userInfo.add(passLabel, gbc); gbc.gridx++; userInfo.add(passField, gbc); JLabel serverLabel = new JLabel("Mail Server: "); JTextField serverField = new JTextField(10); gbc.gridx++; userInfo.add(serverLabel, gbc); gbc.gridx++; userInfo.add(serverField, gbc); JLabel portLabel = new JLabel("Server Port: "); JTextField portField = new JTextField(3); gbc.gridx++; userInfo.add(portLabel, gbc); gbc.gridx++; userInfo.add(portField, gbc); gbc = new GridBagConstraints(); gbc.insets = new Insets(2, 2, 4, 2); gbc.gridx = 0; gbc.gridy = 0; //--- To: CC: and Subject Fields ---// JPanel msgInfo = new JPanel(new GridBagLayout()); JLabel toLabel = new JLabel("To: "); JTextField toField = new JTextField(30); msgInfo.add(toLabel, gbc); gbc.gridx++; msgInfo.add(toField, gbc); JLabel subLabel = new JLabel("Subject: "); JTextField subField = new JTextField(30); gbc.gridx++; msgInfo.add(subLabel, gbc); gbc.gridx++; msgInfo.add(subField, gbc); //--- Body ---// // JPanel bodyPnl = new JPanel(new GridBagLayout()); // gbc = new GridBagConstraints(); // gbc.insets = new Insets(2, 2, 4, 2); // gbc.gridx = 0; // gbc.gridy = 0; JLabel bodyLabel = new JLabel("Body"); bodyLabel.setHorizontalAlignment(JLabel.CENTER); bodyLabel.setFont(size30); JTextArea bodyField = new JTextArea(30, 70); bodyField.setLineWrap(true); bodyField.setWrapStyleWord(true); JScrollPane bodyScroll = new JScrollPane(bodyField); bodyScroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); // bodyScroll.setBounds(getX(), getY(), bodyField.getWidth(), bodyField.getHeight()); setLayout(new GridBagLayout()); gbc = new GridBagConstraints(); gbc.gridx = 0; gbc.gridy = 0; gbc.weightx = 1; gbc.fill = GridBagConstraints.HORIZONTAL; add(userInfo, gbc); gbc.gridy++; add(msgInfo, gbc); gbc.gridy++; gbc.insets = new Insets(10, 10, 4, 10); add(bodyLabel, gbc); gbc.gridy++; gbc.insets = new Insets(4, 10, 10, 10); gbc.weighty = 1; gbc.fill = GridBagConstraints.BOTH; add(bodyScroll, gbc); } } 

Answer 2

问题是因为正在使用FlowLayout Manager。 我用不同的布局管理器解决了你的问题。
在发布解决方案之前，您应该遵循一些提示

1. 更改您的class级名称。 它应该是驼峰式的

2. 尝试调用pack（）而不是setSize（），因为它会自动处理它。 当我用pack（）替换你的setSize（）时，它显示了一个看起来很尴尬的GUI，certificate你的布局和添加元素不合适。

     Font size30 = new Font(null, Font.PLAIN, 30); JPanel pnl = new JPanel(); pnl.setLayout(new BoxLayout(pnl,BoxLayout.Y_AXIS)); Container contentPane = getContentPane(); //--- User Info ---// JPanel userInfo = new JPanel(); JLabel userLabel = new JLabel("Username: "); JTextField userField = new JTextField(12); userInfo.add(userLabel); userInfo.add(userField); JLabel passLabel = new JLabel("Password: "); JTextField passField = new JTextField(10); userInfo.add(passLabel); userInfo.add(passField); JLabel serverLabel = new JLabel("Mail Server: "); JTextField serverField = new JTextField(10); userInfo.add(serverLabel); userInfo.add(serverField); JLabel portLabel = new JLabel("Server Port: "); JTextField portField = new JTextField(3); userInfo.add(portLabel); userInfo.add(portField); //--- To: CC: and Subject Fields ---// JPanel msgInfo = new JPanel(); JLabel toLabel = new JLabel("To: "); JTextField toField = new JTextField(30); msgInfo.add(toLabel); msgInfo.add(toField); JLabel subLabel = new JLabel("Subject: "); JTextField subField = new JTextField(30); msgInfo.add(subLabel); msgInfo.add(subField); //--- Body ---// JLabel bodyLabel = new JLabel("Body"); bodyLabel.setFont(size30); JTextArea bodyField = new JTextArea(30,70); bodyField.setLineWrap(true); bodyField.setWrapStyleWord(true); JScrollPane bodyScroll = new JScrollPane(bodyField); bodyScroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); bodyScroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); pnl.add(userInfo); pnl.add(msgInfo); pnl.add(bodyLabel); pnl.add(bodyScroll); contentPane.add(pnl); setVisible(true); pack();