如何刷新 JFrame [英] How to refresh JFrame
问题描述
我知道有类似的问题，但我有一些不同的问题...
I know there were similar questions but I have some different problem...
我想在单击按钮后删除 JFrame 的所有元素:
I'd like to remove all elements of JFrame after clicking a button:
它有效:
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0)
{
frame.getContentPane().removeAll();
frame.revalidate();
frame.repaint();
}
});
所有元素都消失了.但在那之后我需要在这个 JFrame 上放置元素......在上面的这 3 行之后(在 frame.repaint() 下面)我调用方法 initialize(我调用的方法我在开始时创建了我的窗口):
All elements disappeared. But after that I need to putelements on this JFrame... After these 3 lines above (below frame.repaint()) I call method initialize (method that I call when I create my window at the beginning):
private void initialize()
{
frame = new JFrame();
frame.setBounds(100, 100, 1454, 860);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JButton btnNewSubject = new JButton("New subject");
btnNewSubject.setBounds(647, 788, 137, 23);
frame.getContentPane().add(btnNewSubject);
JButton btnRefresh = new JButton("Refresh");
btnRefresh.setBounds(1339, 788, 89, 23);
frame.getContentPane().add(btnRefresh);
JLabel lblNewLabel = new JLabel("Subject");
lblNewLabel.setBounds(235, 11, 75, 14);
frame.getContentPane().add(lblNewLabel);
JLabel lblOwner = new JLabel("Owner");
lblOwner.setBounds(662, 11, 46, 14);
frame.getContentPane().add(lblOwner);
JLabel lblStatus = new JLabel("Status");
lblStatus.setBounds(883, 11, 46, 14);
frame.getContentPane().add(lblStatus);
JLabel lblDateOfAdded = new JLabel("Date of added");
lblDateOfAdded.setBounds(1104, 11, 116, 14);
frame.getContentPane().add(lblDateOfAdded);
}
什么都没发生.:( JFrame 仍然是空的.即使我调用 revalidate 和 repaint().
Nothing happens. :( JFrame is still empty. Even if I call revalidate and repaint().
怎么了?
推荐答案
您正在此处的方法中创建一个全新的 JFrame
You are creating a completely new JFrame in your method here
frame = new JFrame();
你永远不会显示它，你永远不会在它上面调用 setVisible(true)，所以它会保持不可见.听起来好像您正在创建两个 JFrame 却没有意识到，您正在向第二个未显示的 JFrame 添加组件，但只显示第一个，没有新组件的那个.
and you never display it, you never call setVisible(true) on it, and so it will remain invisible. It almost sounds as if you're creating two JFrames without realizing it, that you are adding components to the second non-displayed JFrame, but are leaving displaying just the first one, the one without new components.
更重要的是，您将需要使用 CardLayout 来帮助您交换 JPanel 视图，因为这种情况正是它所针对的.此外，您的程序使用空布局和 setBounds(...) 会导致刚性 GUI 在一个系统上看起来不错，但在任何其他系统或屏幕分辨率上通常看起来很差.以这种方式创建的程序很难调试、维护和升级.而是使用布局管理器，因为这正是它们的强项:在创建可以轻松增强和更改的复杂、灵活的 GUI 方面.
More importantly, you will want to use a CardLayout to help you swap your JPanel views as this situation is exactly what it's built for. Also, Your program uses null layout and setBounds(...) something that results in a rigid GUI that may look good on one system but will usually look poor on any other system or screen resolution. Programs created this way are very hard to debug, maintain and upgrade. Instead use the layout managers as this is what they excel at: at creating complex flexible GUI's that can be enhanced and changed easily.
请注意，您的 removeAll() 调用不会像 Ludovic 所说的那样删除根窗格，因为您是在 contentPane 而不是 JFrame 上调用它，并且 contentPane 不包含根窗格.
Note that your removeAll() call does not remove the root pane as Ludovic is stating because you're calling this on the contentPane not the JFrame, and the contentPane does not contain the root pane.
编辑
例如，
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
public class CardLayoutEg extends JPanel {
private CardLayout cardlayout = new CardLayout();
private TitlePanel titlePanel = new TitlePanel(this);
private SubjectPanel subjectPanel = new SubjectPanel(this);
public CardLayoutEg() {
setLayout(cardlayout);
add(titlePanel, titlePanel.getName());
add(subjectPanel, subjectPanel.getName());
}
public void nextCard() {
cardlayout.next(this);
}
public void showCard(String key) {
cardlayout.show(this, key);
}
private static void createAndShowGui() {
JFrame frame = new JFrame("CardLayout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new CardLayoutEg());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class TitlePanel extends JPanel {
public static final String TITLE_PANEL = "title panel";
private static final int PREF_W = 900;
private static final int PREF_H = 750;
private static final String TITLE = "My Application Title";
private static final float POINTS = 46f;
private CardLayoutEg cardLayoutEg;
public TitlePanel(CardLayoutEg cardLayoutEg) {
setName(TITLE_PANEL);
this.cardLayoutEg = cardLayoutEg;
JLabel titleLabel = new JLabel(TITLE, SwingConstants.CENTER);
titleLabel.setFont(titleLabel.getFont().deriveFont(Font.BOLD, POINTS));
JButton subjectButton = new JButton(new SubjectAction("Subjects"));
JPanel buttonPanel = new JPanel();
buttonPanel.add(subjectButton);
setLayout(new BorderLayout());
add(titleLabel, BorderLayout.CENTER);
add(buttonPanel, BorderLayout.PAGE_END);
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class SubjectAction extends AbstractAction {
public SubjectAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
cardLayoutEg.showCard(SubjectPanel.SUBJECT_PANEL);
}
}
}
class SubjectPanel extends JPanel {
public static final String SUBJECT_PANEL = "subject panel";
private static final String[] COLUMN_NAMES = {"Subject", "Owner", "Status", "Date Added"};
DefaultTableModel tableModel = new DefaultTableModel(COLUMN_NAMES, 10);
private JTable table = new JTable(tableModel);
private CardLayoutEg cardLayoutEg;
public SubjectPanel(CardLayoutEg cardLayoutEg) {
setBorder(BorderFactory.createTitledBorder("Subject Panel"));
setName(SUBJECT_PANEL);
this.cardLayoutEg = cardLayoutEg;
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(1, 0, 10, 0));
buttonPanel.add(new JButton("New Subject"));
buttonPanel.add(new JButton("Refresh"));
buttonPanel.add(new JButton(new TitleAction("Title")));
buttonPanel.add(new JButton(new ExitAction("Exit")));
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.add(Box.createHorizontalGlue());
bottomPanel.add(buttonPanel);
setLayout(new BorderLayout());
add(new JScrollPane(table), BorderLayout.CENTER);
add(bottomPanel, BorderLayout.PAGE_END);
}
private class TitleAction extends AbstractAction {
public TitleAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
cardLayoutEg.showCard(TitlePanel.TITLE_PANEL);
}
}
private class ExitAction extends AbstractAction {
public ExitAction(String name) {
super(name);
int mnemonic = KeyEvent.VK_X;
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
Component component = (Component) e.getSource();
Window win = SwingUtilities.getWindowAncestor(component);
win.dispose();
}
}
}
这篇关于如何刷新 JFrame的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
