在运行时删除顶级容器 [英] Remove Top-Level Container on Runtime
问题描述
不幸的是，它似乎最近关闭问题还不太清楚。以下是典型输出：
Unfortunately, it looks like this recently closed question was not well understood. Here is the typical output:
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)
我会再次尝试这个问题：如何在运行时k i l * l首次打开的顶级容器，并帮我关闭一个Swing NightMares？
I'll try asking this question again: How can I kil*l on Runtime the first-opened top-Level Container, and help with closing for me one of Swing NightMares?
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();
}
});
}
}
推荐答案
调用 dispose（） 允许主机平台回收重量级对等体消耗的内存，但在之后 之前不能这样做WINDOW_CLOSING 事件在 EventQueue 上处理。即使这样， gc（）也是一个建议。
Invoking dispose() allows the host platform to reclaim memory consumed by the heavyweight peer, but it can't do so until after the WINDOW_CLOSING event is processed on the EventQueue. Even then, gc() is a suggestion.
附录：另一种看噩梦的方法是通过一个分析器。使用 jvisualvm 运行下面的示例，可以看到永远相当的定期集合返回到基线。我用一个人工小的堆开始夸大了垂直轴。其他示例显示此处。当内存非常有限时，我使用了两种方法：
Addendum: Another way to see the nightmare is via a profiler. Running the example below with jvisualvm, one can see that periodic collection never quite returns to baseline. I've exaggerated the vertical axis by starting with an artificially small heap. Additional examples are shown here. When memory is very limited, I've used two approaches:
-
紧急：从命令行循环，启动一个新VM每次。
Emergent: Loop from the command line, starting a new VM each time.
紧急：完全消除重量级组件，无头运行并在 BufferedImage 中使用仅限2D图形和轻量级组件。
Urgent: Eliminate the heavyweight component entirely, running headless and composing in a BufferedImage using 2D graphics and lightweight components only.
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();
}
}
});
}
}
这篇关于在运行时删除顶级容器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！
