检测 JPanel 卸载/关闭事件
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【中文标题】检测 JPanel 卸载/关闭事件【英文标题】：Detecting a JPanel Unloading/Close Events 【发布时间】：2013-12-03 06:46:25 【问题描述】：全部
我有一个 JPanel，说是 JTabbedPane 的容器，其中包含一个设计和一个预览面板。
JPanel 在 JFrame 中，
预览面板包含一个 JME3 画布。
我想要完成的是，每当用户移动到应用程序中的另一个面板时，我可以捕获容器 Jpanel 的卸载并关闭 JME3 应用程序，
我找到了以下主题，
Similar Threads 1
Similar Thread 2
我通过这些线程了解到 HierarchyListener 可能对我有用， 但我被卡住了如何在那里获得特定的面板卸载检测？
谢谢 米希尔
【问题讨论】：
【参考方案1】：有三个 Listener 对这些事件做出反应 AncestorListener、ComponentListener、HierarchyListener
默认情况下 ComponentListener 是可行的
.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.HierarchyEvent;
import java.awt.event.HierarchyListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.AncestorEvent;
import javax.swing.event.AncestorListener;
public class CardlayoutTest extends JFrame
private static final long serialVersionUID = 1L;
public CardLayout card = new CardLayout();
public CardlayoutTest()
JPanel pnlA = new JPanel(new BorderLayout());
pnlA.add(new JButton("A"), BorderLayout.CENTER);
JPanel pnlB = new JPanel(new BorderLayout());
pnlB.add(new JButton("B"), BorderLayout.CENTER);
JPanel pnlC = new JPanel(new BorderLayout());
pnlC.add(new JButton("C"), BorderLayout.CENTER);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(card);
add(pnlA, "A");
add(pnlB, "B");
add(pnlC, "C");
pnlA.addAncestorListener(new EventHandler());
pnlB.addAncestorListener(new EventHandler());
pnlC.addAncestorListener(new EventHandler());
pnlA.addHierarchyListener(new EventHandler());
pnlB.addHierarchyListener(new EventHandler());
pnlB.addHierarchyListener(new EventHandler());
pnlA.addComponentListener(new EventHandler());
pnlB.addComponentListener(new EventHandler());
pnlB.addComponentListener(new EventHandler());
class EventHandler implements AncestorListener, ComponentListener, HierarchyListener
@Override
public void ancestorAdded(AncestorEvent event)
System.out.println("CardlayoutTest.EventHandler.ancestorAdded()");
@Override
public void ancestorMoved(AncestorEvent event)
System.out.println("CardlayoutTest.EventHandler.ancestorMoved()");
@Override
public void ancestorRemoved(AncestorEvent event)
System.out.println("CardlayoutTest.EventHandler.ancestorRemoved()");
@Override
public void hierarchyChanged(HierarchyEvent e)
System.out.println("Components Change: " + e.getChanged());
if ((e.getChangeFlags() & HierarchyEvent.DISPLAYABILITY_CHANGED) != 0)
if (e.getComponent().isDisplayable())
System.out.println("Components DISPLAYABILITY_CHANGED : " + e.getChanged());
else
System.out.println("Components DISPLAYABILITY_CHANGED : " + e.getChanged());
if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0)
if (e.getComponent().isDisplayable())
System.out.println("Components SHOWING_CHANGED : " + e.getChanged());
else
System.out.println("Components SHOWING_CHANGED : " + e.getChanged());
public void componentHidden(ComponentEvent e)
System.out.println(e.getComponent().getClass().getName() + " --- Hidden");
public void componentMoved(ComponentEvent e)
System.out.println(e.getComponent().getClass().getName() + " --- Moved");
public void componentResized(ComponentEvent e)
System.out.println(e.getComponent().getClass().getName() + " --- Resized ");
public void componentShown(ComponentEvent e)
System.out.println(e.getComponent().getClass().getName() + " --- Shown");
public static void main(String[] args)
CardlayoutTest t = new CardlayoutTest();
t.setSize(500, 500);
System.out.println("CardlayoutTest.main()------------------------ FIRST");
t.card.show(t.getContentPane(), "A");
t.setVisible(true);
System.out.print("\n");
try
Thread.sleep(2000);
catch (InterruptedException e)
System.out.println("CardlayoutTest.main()------------------------ SECOND");
t.card.show(t.getContentPane(), "B");
System.out.print("\n");
try
Thread.sleep(2000);
catch (InterruptedException e)
System.out.println("CardlayoutTest.main()------------------------ THIRD");
t.card.show(t.getContentPane(), "C");
System.out.print("\n");
有事件
CardlayoutTest.main()------------------------ FIRST 组件更改： javax.swing.JPanel[,0,0,0x0,invalid,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 DISPLAYABILITY_CHANGED ： javax.swing.JPanel[,0,0,0x0,invalid,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： javax.swing.JPanel[,0,0,0x0,invalid,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 DISPLAYABILITY_CHANGED ： javax.swing.JPanel[,0,0,0x0,invalid,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： javax.swing.JPanel[,0,0,0x0,invalid,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 DISPLAYABILITY_CHANGED ： javax.swing.JPanel[,0,0,0x0,invalid,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true] 组件 SHOWING_CHANGED ： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true] 组件变化： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true] 组件 SHOWING_CHANGED ： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true] 组件变化： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true] 组件 SHOWING_CHANGED ： Listeners.CardlayoutTest[frame0,0,0,500x500,layout=java.awt.BorderLayout,title=,resizable,normal,defaultCloseOperation=EXIT_ON_CLOSE,rootPane=javax.swing.JRootPane[,8,31,484x461,layout=javax.swing. JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true]
CardlayoutTest.EventHandler.ancestorMoved() javax.swing.JPanel --- 调整大小的 javax.swing.JPanel --- 调整大小的 javax.swing.JPanel --- 调整大小的 CardlayoutTest.EventHandler.ancestorMoved() CardlayoutTest.EventHandler.ancestorAdded() CardlayoutTest.main()------------------------ 第二个组件 改变： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 SHOWING_CHANGED ： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： javax.swing.JPanel[,0,0,484x461,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 SHOWING_CHANGED ： javax.swing.JPanel[,0,0,484x461,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： javax.swing.JPanel[,0,0,484x461,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 SHOWING_CHANGED ： javax.swing.JPanel[,0,0,484x461,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=]
CardlayoutTest.EventHandler.ancestorRemoved() javax.swing.JPanel --- 隐藏 CardlayoutTest.EventHandler.ancestorAdded() javax.swing.JPanel --- 显示 javax.swing.JPanel --- 显示 CardlayoutTest.main()------------------------ 第三个组件更改： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 SHOWING_CHANGED ： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件变化： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] 组件 SHOWING_CHANGED ： javax.swing.JPanel[,0,0,484x461,hidden,layout=java.awt.BorderLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=9,maximumSize=,minimumSize=,preferredSize=] CardlayoutTest.EventHandler.ancestorRemoved() javax.swing.JPanel --- 隐藏的 javax.swing.JPanel --- 隐藏
CardlayoutTest.EventHandler.ancestorAdded()
【讨论】：
嗨，我现在就试试，但我已经使用了 grouplayout，但它仍然适用吗？ 是的，在将 ComponentListener 添加到 JPanel（使用 Grouplayout）的情况下，但 LayoutManager 与此侦听器无关【参考方案2】：在面板上实现 AncestorListener，你想知道加载/卸载事件。我添加了一个按钮来显示和隐藏创建的 JPanel。下面是相同的代码。 AncestorListener 告诉我它何时完美加载和卸载。
public class PanelTrial extends javax.swing.JPanel implements AncestorListener
private Container frame;
private javax.swing.JPanel btnPanel;
public PanelTrial(Container frame)
this.frame = frame;
initComponents();
createBtnPanel();
btnPanel.addAncestorListener(this);
// Called on btn click event - to show/hide btnPanel
private void updateRightPanel(boolean showBtnPanel)
jPanel1.removeAll();
GroupLayout layout = (GroupLayout) jPanel1.getLayout();
if (showBtnPanel)
layout.setHorizontalGroup(layout.createSequentialGroup()
.addComponent(btnPanel));
layout.setVerticalGroup(layout.createParallelGroup(
Alignment.TRAILING).addComponent(btnPanel));
else
layout.setHorizontalGroup(layout.createSequentialGroup()
.addComponent(rightPanel));
layout.setVerticalGroup(layout.createParallelGroup(
Alignment.TRAILING).addComponent(rightPanel));
jPanel1.validate();
this.validate();
@Override
public void ancestorAdded(AncestorEvent e)
if (e.getSource() == btnPanel)
System.out.println("BTNSPANEL LOADED / ADDED");
@Override
public void ancestorMoved(AncestorEvent e)
// This is of no use for your purpose
System.out.println("Anc Moved - " + e.getSource());
@Override
public void ancestorRemoved(AncestorEvent e)
if (e.getSource() == btnPanel)
System.out.println("BTNSPANEL UNLOADED / REMOVED");
【讨论】：
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