Java-在运行时删除顶级容器
不幸的是，似乎这个最近关闭的问题没有得到很好的理解。这是典型的输出：
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)
我再试一次问这个问题：我如何能K 我 L * L于运行第一开顶层Container，并与关闭对我摇摆恶梦帮助？
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();
}
});
}
}
回答：
调用dispose()允许主机平台回收重量级对等方消耗的内存，但只有在事件在上处理后才能这样做。即使这样，也是一个建议。WINDOW_CLOSINGEventQueuegc()
附录：查看噩梦的另一种方法是通过探查器。使用运行下面的示例jvisualvm，你可以看到定期收集永远不会完全返回基线。我从人为的小堆开始夸大了垂直轴。其他示例在此处显示。当内存非常有限时，我使用了两种方法：
紧急：从命令行循环，每次启动一个新的VM。
紧急：完全消除重量级组件，无头运行，
BufferedImage仅使用2D图形和轻量级组件组成。
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();
}
}
});
}
}
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