以下示例允許窗口顯示,隱藏,處置和關閉(通過發送事件)。當窗口打開?如何知道窗口在沒有監聽窗口事件的情況下打開?
示例顯示,該窗口僅打開一次 - 第一組可見。即使窗戶被丟棄,然後再次顯示,它也不會經歷「開放」事件。
爲什麼?
如何知道是否在不編寫處理程序並跟蹤此事件的情況下打開窗口?
如何關閉窗口,使其在設置可見時再次發生打開事件?即如何將窗口對象返回到初始狀態?
是否有任何其他狀態或事件可以具有所需的屬性?
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.AbstractAction;
import javax.swing.AbstractListModel;
import javax.swing.ComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.ListDataListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Tester_JFrame_Closing_01 {
private static Logger log = LoggerFactory.getLogger(Tester_JFrame_Closing_01.class);
protected static Toolkit toolkit = Toolkit.getDefaultToolkit();
protected static EventQueue eventQueue = toolkit.getSystemEventQueue();
public static enum CloseOperation {
DO_NOTHING_ON_CLOSE(JFrame.DO_NOTHING_ON_CLOSE),
HIDE_ON_CLOSE(JFrame.HIDE_ON_CLOSE),
DISPOSE_ON_CLOSE(JFrame.DISPOSE_ON_CLOSE),
EXIT_ON_CLOSE(JFrame.EXIT_ON_CLOSE)
;
public static ComboBoxModel newModel() {
return new ComboBoxModel() {
private CloseOperation selected = HIDE_ON_CLOSE;
@SuppressWarnings("serial")
private final AbstractListModel core = new AbstractListModel() {
@Override
public int getSize() {
return values().length;
}
@Override
public Object getElementAt(int index) {
return values()[index];
}
};
@Override
public int getSize() {
return core.getSize();
}
@Override
public Object getElementAt(int index) {
return core.getElementAt(index);
}
@Override
public void addListDataListener(ListDataListener l) {
core.addListDataListener(l);
}
@Override
public void removeListDataListener(ListDataListener l) {
core.removeListDataListener(l);
}
@Override
public void setSelectedItem(Object anItem) {
selected = (CloseOperation) anItem;
}
@Override
public Object getSelectedItem() {
return selected;
}
};
}
public final int Value;
private CloseOperation(int value) {
this.Value = value;
}
@Override
public String toString() {
switch(this) {
case DISPOSE_ON_CLOSE:
return "DISPOSE_ON_CLOSE";
case HIDE_ON_CLOSE:
return "HIDE_ON_CLOSE";
case DO_NOTHING_ON_CLOSE:
return "DO_NOTHING_ON_CLOSE";
case EXIT_ON_CLOSE:
return "EXIT_ON_CLOSE";
default:
return "<UNKNOWN>";
}
}
}
public static void main(String[] args) {
WindowAdapter windowAdapter = new WindowAdapter() {
@Override
public void windowClosed(WindowEvent e) {
log.debug("windowClosed");
}
@Override
public void windowClosing(WindowEvent e) {
log.debug("windowClosing");
}
@Override
public void windowOpened(WindowEvent e) {
log.debug("windowOpened");
}
};
final JFrame frame = new JFrame("Controlled window");
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
frame.addWindowListener(windowAdapter);
final WindowEvent closeEvent = new WindowEvent(frame, WindowEvent.WINDOW_CLOSING);
@SuppressWarnings("serial")
AbstractAction closeAction = new AbstractAction("close") {
@Override
public void actionPerformed(ActionEvent e) {
eventQueue.postEvent(closeEvent);
}
};
@SuppressWarnings("serial")
AbstractAction hideAction = new AbstractAction("hide") {
@Override
public void actionPerformed(ActionEvent e) {
frame.setVisible(false);
}
};
@SuppressWarnings("serial")
AbstractAction showAction = new AbstractAction("show") {
@Override
public void actionPerformed(ActionEvent e) {
frame.setVisible(true);
}
};
@SuppressWarnings("serial")
AbstractAction disposeAction = new AbstractAction("dispose") {
@Override
public void actionPerformed(ActionEvent e) {
frame.dispose();
}
};
JButton closeButton = new JButton(closeAction);
JButton hideButton = new JButton(hideAction);
JButton showButton = new JButton(showAction);
JButton disposeButton = new JButton(disposeAction);
ComboBoxModel closeOperationModel = CloseOperation.newModel();
final JComboBox closeOperationCombo = new JComboBox(closeOperationModel);
closeOperationCombo.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
log.debug("closeOperationCombo.actionPerformed({})", e);
frame.setDefaultCloseOperation(((CloseOperation)closeOperationCombo.getSelectedItem()).Value);
}
});
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.add(showButton);
buttonPanel.add(hideButton);
buttonPanel.add(disposeButton);
buttonPanel.add(closeButton);
buttonPanel.add(closeOperationCombo);
JFrame controlFrame = new JFrame("Controller window");
controlFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
controlFrame.setLayout(new FlowLayout());
controlFrame.add(buttonPanel, BorderLayout.SOUTH);
controlFrame.pack();
controlFrame.setLocation(100, 100);
controlFrame.setVisible(true);
frame.setBounds(100, 100 + controlFrame.getHeight(), controlFrame.getWidth(), 480);
}
}
INCREDIBLE
他們有一個字段中指定Window.state
他們甚至不初始化(因此它是零),那麼他們測試它在show()
方法一次並將其設置爲1
,如果它是0
。這是唯一的地方state
被使用,這裏windowOpened
被解僱。沒有任何代碼將state
返回到0
任何地方。而且,他們在Frame
子類中放棄了這個state
變量,並用新名稱覆蓋它,並且新名稱按住了一些新的狀態,包括圖標化和類似,並忘記了已打開的位!涼!
'eventQueue.postEvent(closeEvent);'爲什麼? – MadProgrammer 2013-03-06 23:40:59
@MadProgrammer,而不是直接調用'setVisible(false)'或'dispose()',這就像用戶點擊框架的關閉按鈕。然後將執行默認關閉操作。 – camickr 2013-03-07 04:13:21
@camickr好吧,我還是抓我頭:P – MadProgrammer 2013-03-07 04:45:29