[英]Remove Top-Level Container on Runtime
不幸的是，看起來這個最近封閉的問題還不太清楚。 這是典型的輸出：
run:
Trying to Remove JDialog
Remove Cycle Done :-)
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 1
-----------------------------------------------------------
Trying to Remove JDialog
Remove Cycle Done :-)
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 2
-----------------------------------------------------------
Trying to Remove JDialog
Remove Cycle Done :-)
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 3
-----------------------------------------------------------
Trying to Remove JDialog
Remove Cycle Done :-)
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
*** End of Cycle Without Success, Exit App ***
BUILD SUCCESSFUL (total time: 13 seconds)
我再試一次問這個問題：我如何能K上運行的第一個開頂級I L * L Container ，並與關閉對我搖擺惡夢幫助嗎？
import java.awt.*;
import java.awt.event.WindowEvent;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
public class RemoveDialogOnRuntime extends JFrame {
private static final long serialVersionUID = 1L;
private int contID = 1;
private boolean runProcess;
private int top = 20;
private int left = 20;
private int maxLoop = 0;
public RemoveDialogOnRuntime() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300, 300));
setTitle("Remove Dialog On Runtime");
setLocation(150, 150);
pack();
setVisible(true);
Point loc = this.getLocation();
top += loc.x;
left += loc.y;
AddNewDialog();
}
private void AddNewDialog() {
DialogRemove firstDialog = new DialogRemove();
remWins();
}
private void remWins() {
runProcess = true;
Thread th = new Thread(new RemTask());
th.setDaemon(false);
th.setPriority(Thread.MIN_PRIORITY);
th.start();
}
private class RemTask implements Runnable {
@Override
public void run() {
while (runProcess) {
Window[] wins = Window.getWindows();
for (int i = 0; i < wins.length; i++) {
if (wins[i] instanceof JDialog) {
System.out.println(" Trying to Remove JDialog");
wins[i].setVisible(false);
wins[i].dispose();
WindowEvent windowClosing = new WindowEvent(wins[i], WindowEvent.WINDOW_CLOSING);
wins[i].dispatchEvent(windowClosing);
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(windowClosing);
Runtime runtime = Runtime.getRuntime();
runtime.gc();
runtime.runFinalization();
}
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
Logger.getLogger(RemoveDialogOnRuntime.class.getName()).log(Level.SEVERE, null, ex);
}
}
wins = null;
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
System.out.println(" Remove Cycle Done :-)");
Runtime.getRuntime().runFinalization();
Runtime.getRuntime().gc();
runProcess = false;
}
});
}
pastRemWins();
}
}
private void pastRemWins() {
System.out.println(" Checking if still exists any of TopLayoutContainers");
Window[] wins = Window.getWindows();
for (int i = 0; i < wins.length; i++) {
if (wins[i] instanceof JFrame) {
System.out.println("JFrame");
wins[i].setVisible(true);
} else if (wins[i] instanceof JDialog) {
System.out.println("JDialog");
wins[i].setVisible(true);
}
}
if (wins.length > 1) {
wins = null;
maxLoop++;
if (maxLoop <= 3) {
System.out.println(" Will Try Remove Dialog again, CycleNo. " + maxLoop);
System.out.println(" -----------------------------------------------------------");
remWins();
} else {
System.out.println(" -----------------------------------------------------------");
System.out.println("*** End of Cycle Without Success, Exit App ***");
closeMe();
}
}
}
private void closeMe() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
System.exit(0);
}
});
}
private class DialogRemove extends JDialog {
private static final long serialVersionUID = 1L;
DialogRemove(final Frame parent) {
super(parent, "SecondDialog " + (contID++));
setLocation(top, left);
top += 20;
left += 20;
setPreferredSize(new Dimension(200, 200));
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.MODELESS);
pack();
setVisible(true);
}
private DialogRemove() {
setTitle("SecondDialog " + (contID++));
setLocation(top, left);
top += 20;
left += 20;
setPreferredSize(new Dimension(200, 200));
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.MODELESS);
pack();
setVisible(true);
}
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
RemoveDialogOnRuntime superConstructor = new RemoveDialogOnRuntime();
}
});
}
}
調用dispose()允許主機平台回收重量級對等體消耗的內存，但直到在 EventQueue上處理WINDOW_CLOSING事件之后才能這樣做。 即使這樣， gc()也是一個建議。
附錄：另一種看噩夢的方法是通過剖析器。 使用jvisualvm運行下面的示例，可以看到定期收集永遠不會完全返回到基線。 我從一個人為的小堆開始誇大了垂直軸。 此處顯示了其他示例。 當內存非常有限時，我使用了兩種方法：
緊急：從命令行循環，每次啟動一個新的VM。
緊急：完全消除重量級組件，僅使用2D圖形和輕量級組件在BufferedImage運行無頭和組合。
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.WindowEvent;
import javax.swing.JDialog;
/** @see https://stackoverflow.com/questions/6309407 */
public class DialogClose extends JDialog {
public DialogClose(int i) {
this.setTitle("Dialog " + String.valueOf(i));
this.setPreferredSize(new Dimension(320, 200));
}
private void display() {
this.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
passSomeTime();
this.setVisible(false);
this.dispatchEvent(new WindowEvent(
this, WindowEvent.WINDOW_CLOSING));
this.dispose();
passSomeTime();
}
private void passSomeTime() {
try {
Thread.sleep(100);
} catch (InterruptedException ie) {
ie.printStackTrace(System.err);
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
int count = 0;
while (true) {
new DialogClose(count++).display();
}
}
});
}
}
我完全重寫了你的例子：
setLocation() ，未使用的構造函數......） javax.swing.Timer而不是Thread來處理對話框 Thread （在EDT中不是一個好主意） Window.getWindows()是否為2 （而不是1 ），因為在Swing中，如果打開沒有父對象的對話框，則會創建一個特殊的不可見框架以將其用作父對象（對於實際上所有無主對話框），一旦創建，該框架就無法刪除。 結果摘錄如下：
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class RemoveDialogOnRuntime extends JFrame {
private static final long serialVersionUID = 1L;
private boolean runProcess;
private int maxLoop = 0;
private Timer timer;
public RemoveDialogOnRuntime() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300, 300));
setTitle("Remove Dialog On Runtime");
setLocation(150, 150);
pack();
setVisible(true);
addNewDialog();
}
private void addNewDialog() {
DialogRemove firstDialog = new DialogRemove();
remWins();
}
private void remWins() {
runProcess = true;
timer = new Timer(1000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (runProcess) {
for (Window win: Window.getWindows()) {
if (win instanceof JDialog) {
System.out.println(" Trying to Remove JDialog");
win.dispose();
}
}
System.out.println(" Remove Cycle Done :-)");
runProcess = false;
new Thread() {
@Override
public void run() {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
Runtime.getRuntime().gc();
}
}.start();
} else {
pastRemWins();
runProcess = true;
}
}
});
timer.setRepeats(true);
timer.start();
}
private void pastRemWins() {
System.out.println(" Checking if still exists any of TopLayoutContainers");
Window[] wins = Window.getWindows();
for (int i = 0; i < wins.length; i++) {
if (wins[i] instanceof JFrame) {
System.out.println("JFrame");
} else if (wins[i] instanceof JDialog) {
System.out.println("JDialog");
} else {
System.out.println(wins[i].getClass().getSimpleName());
}
}
// We must expect 2 windows here: this (RemoveDialogOnRuntime) and the parent of all parentless dialogs
if (wins.length > 2) {
wins = null;
maxLoop++;
if (maxLoop <= 3) {
System.out.println(" Will Try Remove Dialog again, CycleNo. " + maxLoop);
System.out.println(" -----------------------------------------------------------");
remWins();
} else {
System.out.println(" -----------------------------------------------------------");
System.out.println("*** End of Cycle Without Success, Exit App ***");
closeMe();
}
} else {
timer.stop();
}
}
private void closeMe() {
System.exit(0);
}
private class DialogRemove extends JDialog {
private static final long serialVersionUID = 1L;
private DialogRemove() {
setTitle("SecondDialog");
setPreferredSize(new Dimension(200, 200));
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.MODELESS);
pack();
setVisible(true);
}
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
RemoveDialogOnRuntime superConstructor = new RemoveDialogOnRuntime();
}
});
}
}
重要的結論是：
Window.getWindows()移除已放置的對話框（這對我來說看起來像一個錯誤，但我認為原因是Swing將WeakReference保留到所有窗口，並且此WeakReference直到已發生GC。 希望這能為您的問題提供清晰完整的答案。
意圖吹走所有關於EDT的疑慮並確認trashgod更新建議，然后輸出到控制台
run:
7163 KB used before GC
Trying to Remove JDialog
Remove Cycle Done :-)
405 KB used after GC
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 1
-----------------------------------------------------------
3274 KB used before GC
Trying to Remove JDialog
Remove Cycle Done :-)
403 KB used after GC
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 2
-----------------------------------------------------------
3271 KB used before GC
Trying to Remove JDialog
Remove Cycle Done :-)
406 KB used after GC
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
Will Try Remove Dialog again, CycleNo. 3
-----------------------------------------------------------
3275 KB used before GC
Trying to Remove JDialog
Remove Cycle Done :-)
403 KB used after GC
Checking if still exists any of TopLayoutContainers
JFrame
JDialog
-----------------------------------------------------------
*** End of Cycle Without Success, Exit App ***
BUILD SUCCESSFUL (total time: 26 seconds)
來自代碼
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.WindowEvent;
import javax.swing.*;
public class RemoveDialogOnRuntime extends JFrame {
private static final long serialVersionUID = 1L;
private int contID = 1;
private boolean runProcess;
private int top = 20;
private int left = 20;
private int maxLoop = 0;
private javax.swing.Timer timer = null;
public RemoveDialogOnRuntime() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300, 300));
setTitle("Remove Dialog On Runtime");
setLocation(150, 150);
pack();
setVisible(true);
Point loc = this.getLocation();
top += loc.x;
left += loc.y;
AddNewDialog();
}
private void AddNewDialog() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
DialogRemove firstDialog = new DialogRemove();
startAA();
}
});
}
private void startAA() {
timer = new javax.swing.Timer(5000, updateAA());
timer.setRepeats(false);
timer.start();
}
public Action updateAA() {
return new AbstractAction("text load action") {
private static final long serialVersionUID = 1L;
@Override
public void actionPerformed(ActionEvent e) {
timer.stop();
if (SwingUtilities.isEventDispatchThread()) {
Runnable doRun = new Runnable() {
@Override
public void run() {
remWins();
}
};
SwingUtilities.invokeLater(doRun);
} else {
Runnable doRun = new Runnable() {
@Override
public void run() {
remWins();
}
};
SwingUtilities.invokeLater(doRun);
}
}
};
}
private void remWins() {
Runtime runtime = Runtime.getRuntime();
long total = runtime.totalMemory();
long free = runtime.freeMemory();
long max = runtime.maxMemory();
long used = total - free;
System.out.println(Math.round(used / 1e3) + " KB used before GC");
Window[] wins = Window.getWindows();
for (int i = 0; i < wins.length; i++) {
if (wins[i] instanceof JDialog) {
System.out.println(" Trying to Remove JDialog");
wins[i].setVisible(false);
wins[i].dispose();
WindowEvent windowClosing = new WindowEvent(wins[i], WindowEvent.WINDOW_CLOSING);
wins[i].dispatchEvent(windowClosing);
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(windowClosing);
runtime = Runtime.getRuntime();
runtime.gc();
runtime.runFinalization();
}
}
wins = null;
System.out.println(" Remove Cycle Done :-)");
runtime.runFinalization();
runtime.gc();
runtime = Runtime.getRuntime();
total = runtime.totalMemory();
free = runtime.freeMemory();
max = runtime.maxMemory();
used = total - free;
System.out.println(Math.round(used / 1e3) + " KB used after GC");
startOO();
}
private void startOO() {
timer = new javax.swing.Timer(5000, updateOO());
timer.setRepeats(false);
timer.start();
}
public Action updateOO() {
return new AbstractAction("text load action") {
private static final long serialVersionUID = 1L;
@Override
public void actionPerformed(ActionEvent e) {
timer.stop();
timer.stop();
if (SwingUtilities.isEventDispatchThread()) {
Runnable doRun = new Runnable() {//really contraproductive just dealayed
@Override
public void run() {
pastRemWins();
}
};
SwingUtilities.invokeLater(doRun);
} else {
Runnable doRun = new Runnable() {
@Override
public void run() {
pastRemWins();
}
};
SwingUtilities.invokeLater(doRun);
}
}
};
}
private void pastRemWins() {
System.out.println(" Checking if still exists any of TopLayoutContainers");
Window[] wins = Window.getWindows();
for (int i = 0; i < wins.length; i++) {
if (wins[i] instanceof JFrame) {
System.out.println("JFrame");
wins[i].setVisible(true);
} else if (wins[i] instanceof JDialog) {
System.out.println("JDialog");
wins[i].setVisible(true);
}
}
if (wins.length > 1) {
wins = null;
maxLoop++;
if (maxLoop <= 3) {
System.out.println(" Will Try Remove Dialog again, CycleNo. " + maxLoop);
System.out.println(" -----------------------------------------------------------");
remWins();
} else {
System.out.println(" -----------------------------------------------------------");
System.out.println("*** End of Cycle Without Success, Exit App ***");
closeMe();
}
}
startAA();
}
private void closeMe() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
System.exit(0);
}
});
}
private class DialogRemove extends JDialog {
private static final long serialVersionUID = 1L;
DialogRemove(final Frame parent) {
super(parent, "SecondDialog " + (contID++));
setLocation(top, left);
top += 20;
left += 20;
setPreferredSize(new Dimension(200, 200));
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.MODELESS);
pack();
setVisible(true);
}
private DialogRemove() {
setTitle("SecondDialog " + (contID++));
setLocation(top, left);
top += 20;
left += 20;
setPreferredSize(new Dimension(200, 200));
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.MODELESS);
pack();
setVisible(true);
}
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
RemoveDialogOnRuntime superConstructor = new RemoveDialogOnRuntime();
}
});
}
}
我不確定你的問題是關於“垃圾收集”還是關於如何識別可見的對話框。
您無法控制垃圾收集何時完成。 調用gc（）方法只是一個建議。
如果要忽略“已處置”對話框，則可以使用isDisplayable（）方法檢查其狀態。
通過以下程序，我得到了一些有趣的結果。 我做的第一個更改是在對話框中添加一些組件，以便為每個對話框使用更多資源，這將增加資源被垃圾收集的機會。
在我的機器上，我發現如果我
a）創建5個對話框
b）關閉對話框
c）創建5個對話框
然后前5個似乎是垃圾收集。
但是，如果我創建5，然后關閉然后創建1，然后關閉，它似乎不起作用。
底線是你不能依賴垃圾收集何時完成，所以我建議你使用isDisplayable（）方法來確定如何進行處理。 “顯示對話框”按鈕使用此方法作為顯示輸出的一部分。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class DialogSSCCE extends JPanel
{
public static int count;
public DialogSSCCE()
{
JButton display = new JButton("Display Dialogs");
display.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println();
System.out.println("Display Dialogs");
for (Window window: Window.getWindows())
{
if (window instanceof JDialog)
{
JDialog dialog = (JDialog)window;
System.out.println("\t" + dialog.getTitle() + " " + dialog.isDisplayable());
}
}
}
});
add( display );
JButton open = new JButton("Create Dialog");
open.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println();
System.out.println("Create Dialog");
JDialog dialog = new JDialog();
dialog.getContentPane().setLayout(null);
for (int i = 0; i < 200; i++)
{
dialog.add( new JTextField("some text") );
}
dialog.setTitle("Dialog " + count++);
dialog.setLocation(count * 25, count * 25);
dialog.setVisible(true);
System.out.println("\tCreated " + dialog.getTitle());
}
});
add( open );
JButton close = new JButton("Close Dialogs");
close.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println();
System.out.println("Close Dialogs");
for (Window window: Window.getWindows())
{
if (window instanceof JDialog)
{
JDialog dialog = (JDialog)window;
System.out.println("\tClosing " + dialog.getTitle());
dialog.dispose();
}
}
Runtime.getRuntime().gc();
}
});
add( close );
}
private static void createAndShowUI()
{
JFrame frame = new JFrame("DialogSSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( new DialogSSCCE() );
frame.pack();
frame.setLocationRelativeTo( null );
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowUI();
}
});
}
}
在最終釋放某些資源之前， AppContext定義了超時。 這設置為5秒鍾。 因此，如果您再等待五秒鍾，則上下文將處理（最后）對話框的引用。
wins = null;
Thread.sleep(5000);
指定頂級容器的ContentPane是否有好處？
[英]Is there an advantage to specifying the ContentPane of a top-level container?
如何在整個應用程序中引用頂級容器而不使其成為單例？
[英]How to reference top-level container throughout application without making it a singleton?
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