java是否将焦点赋予不是焦点窗口子级的面板？

Question

我正在用Java创建一个内部工具。两者由两个JPanels组成，预计将在两个单独的屏幕上运行。我希望能够单击JButton，它是JFrame A的一部分，它将向JFrame B发送键盘操作

不幸的是，我似乎不能这样做，因为JFrame B没有焦点，并且我不能使用任何请求Focus方法，因为JFrame B不是Focus Window（JFrame A是）的子对象

所以，我怎样才能给予JFrame B焦点，尽管它不是Focus Window的子对象，或者将Keyboard Event发送给它将在没有焦点的情况下响应的JFrame B

Answer 1

在两个JFrames之间管理焦点是如此困难，最好只创建一个JFrame，其他Top-level Containers将是JDialogs，创建一个/两个JDialog(s)，并通过删除所有JComponents来重用

基本上是：

EventQueue.invokeLater(new Runnable() {

   @Override
     public void run() {
         someComponent.grabFocus();
         someComponent.requestFocus();//or inWindow depends if Swing or Awt
     }
});

但在两个JFrames之间有点复杂，只是一个基本且未完成的示例（基于old.good.sun.forums.com的代码）

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PMDialog extends JDialog {

    private static final long serialVersionUID = 1L;
    private boolean modal = false;
    private WindowAdapter parentWindowListener;
    private Window owner;
    private JFrame blockedFrame = new JFrame("Blocked Frame");
    private JFrame noBlockedFrame = new JFrame("No Blocked Frame");

    public PMDialog() {
        noBlockedFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        noBlockedFrame.getContentPane().add(new JButton(new AbstractAction("Test button") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent evt) {
                System.out.println("Non blocked button pushed");
                /*if (blockedFrame.isVisible()) {
                noBlockedFrame.setVisible(false);
                } else {
                blockedFrame.setVisible(true);
                }*/
                noBlockedFrame.setVisible(true);
                blockedFrame.setVisible(true);
            }
        }));
        noBlockedFrame.setSize(200, 200);
        noBlockedFrame.setVisible(true);
        blockedFrame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
        blockedFrame.getContentPane().add(new JButton(new AbstractAction("Test Button") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent evt) {
                final PMDialog pmd = new PMDialog(blockedFrame, "Partial Modal Dialog", true);
                pmd.setSize(200, 100);
                pmd.setLocationRelativeTo(blockedFrame);
                pmd.getContentPane().add(new JButton(new AbstractAction("Test button") {

                    private static final long serialVersionUID = 1L;

                    @Override
                    public void actionPerformed(ActionEvent evt) {
                        System.out.println("Blocked button pushed");
                        pmd.setVisible(false);
                        blockedFrame.setVisible(false);
                        noBlockedFrame.setVisible(true);
                    }
                }));
                pmd.setDefaultCloseOperation(PMDialog.DISPOSE_ON_CLOSE);
                pmd.setVisible(true);
                System.out.println("Returned from Dialog");
            }
        }));
        blockedFrame.setSize(200, 200);
        blockedFrame.setLocation(300, 0);
        blockedFrame.setVisible(false);
    }

    public PMDialog(JDialog parent, String title, boolean isModal) {
        super(parent, title, false);
        initDialog(parent, title, isModal);
    }

    public PMDialog(JFrame parent, String title, boolean isModal) {
        super(parent, title, false);
        initDialog(parent, title, isModal);
    }

    private void initDialog(Window parent, String title, boolean isModal) {
        owner = parent;
        modal = isModal;
        parentWindowListener = new WindowAdapter() {

            @Override
            public void windowActivated(WindowEvent e) {
                if (isVisible()) {
                    System.out.println("Dialog.getFocusBack()");
                    getFocusBack();
                }
            }
        };
    }

    private void getFocusBack() {
        Toolkit.getDefaultToolkit().beep();
        super.setVisible(false);
        super.pack();
        super.setLocationRelativeTo(owner);
        super.setVisible(true);
        super.toFront();
    }

    @Override
    public void dispose() {
        owner.setEnabled(true);
        owner.setFocusableWindowState(true);
        super.dispose();
    }

    @Override
    @SuppressWarnings("deprecation")
    public void hide() {
        owner.setEnabled(true);
        owner.setFocusableWindowState(true);
        super.hide();
    }

    @Override
    public void setVisible(boolean visible) {
        boolean blockParent = (visible && modal);
        owner.setEnabled(!blockParent);
        owner.setFocusableWindowState(!blockParent);
        super.setVisible(visible);
        if (blockParent) {
            System.out.println("Adding listener to parent ...");
            owner.addWindowListener(parentWindowListener);
            try {
                if (SwingUtilities.isEventDispatchThread()) {
                    System.out.println("EventDispatchThread");
                    EventQueue theQueue = getToolkit().getSystemEventQueue();
                    while (isVisible()) {
                        AWTEvent event = theQueue.getNextEvent();
                        Object src = event.getSource();
                        if (event instanceof ActiveEvent) {
                            ((ActiveEvent) event).dispatch();
                        } else if (src instanceof Component) {
                            ((Component) src).dispatchEvent(event);
                        }
                    }
                } else {
                    System.out.println("OUTSIDE EventDispatchThread");
                    synchronized (getTreeLock()) {
                        while (isVisible()) {
                            try {
                                getTreeLock().wait();
                            } catch (InterruptedException e) {
                                break;
                            }
                        }
                    }
                }
            } catch (Exception ex) {
                ex.printStackTrace();
                System.out.println("Error from EDT ... : " + ex);
            }
        } else {
            System.out.println("Removing listener from parent ...");
            owner.removeWindowListener(parentWindowListener);
            owner.setEnabled(true);
            owner.setFocusableWindowState(true);
        }
    }

    @Override
    public void setModal(boolean modal) {
        this.modal = modal;
    }

    public static void main(String args[]) {
        PMDialog pMDialog = new PMDialog();
    }
}

编辑：关于如何将焦点添加到JDialog是否有camickr的优秀Woodoo Dialog Focus但是AncestorListener不是我喜欢的Java，对我来说太抽象了

Answer 2

没有人说你不能让一个Action向另一个发送消息。在这个example，Enter也需要Clear，因此它转发ActionEvent。还要注意，每个NumberButton将两个击键绑定到Click。在您的情况下，您可能必须删除现有绑定，并可能在另一个窗口上调用^{}。注意支持@mKorbel答案的注意事项

Answer 3

这是一个Swing GUI（您没有提到或向GUI库添加标记）？如果是这样，请考虑使用^ a1}，它与焦点侦听器相比可以更加灵活。p>