是否可以使用keylistener显示先前隐藏的JFrame

Question

这是我的代码，我基本上只是为最常见的侦听器做了一个测试器，以后我可能会在以后的项目中使用它，主要的问题是在底部的键侦听器中，我试图重新显示框架，但我认为只是无法做到这一点，请帮助ps：不知道为什么进口不正确。

package newpackage;

import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JSeparator;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class NewClass1 extends JFrame {


private JLabel item1,infomouse,infoclicks,infoKeys,writehere;
private JButton button1,button2,button3;
private JTextArea text1,status,KeyStatus;
private JTextField text2,text3,mouse,clicks,test;
private JSeparator sep1;
private int clicknumber;

public NewClass1() {
    super("Listener Tests");
    setLayout(null);
    sep1 = new JSeparator();

    button1 = new JButton("Button1");
    button2 = new JButton("Button2");
    button3 = new JButton("Button3");
    item1 = new JLabel("Button Status :");
    infomouse = new JLabel("Mouse Status :");
    infoclicks = new JLabel("Nº of clicks :");
    infoKeys = new JLabel("Keyboard status:");
    writehere = new JLabel("Write here: ");


    text1 = new JTextArea();
    text2 = new JTextField(20);
    text3 = new JTextField(20);
    status = new JTextArea();
    mouse  = new JTextField(20);
    clicks = new JTextField(4);
    KeyStatus = new JTextArea();
    test = new JTextField(3);
    clicks.setText(String.valueOf(clicknumber));

    text1.setEditable(true);
    text2.setEditable(false);
    text3.setEditable(false);
    status.setEditable(false);
    mouse.setEditable(false);
    clicks.setEditable(false);
    KeyStatus.setEditable(false);

    text1.setBounds(135, 310, 150, 20);
    text2.setBounds(135, 330, 150, 20);
    text3.setBounds(135, 350, 150, 20);
    status.setBounds(15, 20, 240, 20);
    infomouse.setBounds(5,45,120,20);
    infoKeys.setBounds(5,90,120,20);
    KeyStatus.setBounds(15,115,240,85);
    test.setBounds(15,225,240,20);
    mouse.setBounds(15,70,100,20);
    infoclicks.setBounds(195, 45, 140, 20);
    clicks.setBounds(195, 70, 60, 20);

    item1.setBounds(5, 0, 120, 20);
    button1.setBounds(10, 310, 115, 20);
    button2.setBounds(10, 330, 115, 20);
    button3.setBounds(10, 350, 115, 20);
    sep1.setBounds(5, 305, 285, 10);

    sep1.setBackground(Color.BLACK);
    status.setBackground(Color.LIGHT_GRAY);

    button1.addActionListener(new button1list());
    button2.addActionListener(new button1list());
    button3.addActionListener(new button1list());

    button1.addMouseListener(new MouseList());
    button2.addMouseListener(new MouseList());
    button3.addMouseListener(new MouseList());
    getContentPane().addMouseListener(new MouseList());
    test.addKeyListener(new KeyList());
    this.addKeyListener(new KeyList());
    test.requestFocus();

    add(item1);
    add(button1);
    add(button2);
    add(button3);
    add(text1);
    add(text2);
    add(text3);
    add(status);
    add(infomouse);
    add(mouse);
    add(infoclicks);
    add(clicks);
    add(infoKeys);
    add(KeyStatus);
    add(test);
    add(sep1);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    try{
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    }catch (Exception e){System.out.println("Error");}
    SwingUtilities.updateComponentTreeUI(this);
    setSize(300, 400);
    setResizable(false);
    setVisible(true);
    test.setFocusable(true);
    test.setFocusTraversalKeysEnabled(false);
    setLocationRelativeTo(null);
}

public class button1list implements ActionListener {

    public void actionPerformed(ActionEvent e) {
        String buttonpressed = e.getActionCommand();
        if (buttonpressed.equals("Button1")) {
            text1.setText("just");
        } else if (buttonpressed.equals("Button2")) {
            text2.setText(text2.getText()+"testing ");
        } else if (buttonpressed.equals("Button3")) {
            text3.setText("this");
        } 
    }
}
    public class MouseList implements MouseListener{
        public void mouseEntered(MouseEvent e){
        if(e.getSource()==button1){
                status.setText("button 1 hovered");
            }
        else if(e.getSource()==button2){
                status.setText("button 2 hovered");
            }
        else if(e.getSource()==button3){
                status.setText("button 3 hovered");
            }
        }
        public void mouseExited(MouseEvent e){
                status.setText("");
        }
        public void mouseReleased(MouseEvent e){
            if(!status.getText().equals("")){
                status.replaceRange("", 0, 22);
            }
        }
        public void mousePressed(MouseEvent e){
            if(e.getSource()==button1){
                status.setText("button 1 being pressed");
            }
        else if(e.getSource()==button2){
                status.setText("button 2 being pressed");
            }
        else if(e.getSource()==button3){
                status.setText("button 3 being pressed");

            }
        }
        public void mouseClicked(MouseEvent e){
            clicknumber++;
            mouse.setText("mouse working");
            clicks.setText(String.valueOf(clicknumber));
      }
 }
    public class KeyList implements KeyListener{
        public void keyReleased(KeyEvent e){}
        public void keyPressed(KeyEvent e){
            KeyStatus.setText("");
            test.setText("");
            String full = e.paramString();
            String [] temp = null;
            temp = full.split(",");
            for(int i=0; i<7 ;i++){
            KeyStatus.append(temp[i] + "\n");
            }
            if(e.getKeyChar()=='h'){setVisible(false);
                test.requestFocus();
            }
            if(e.getKeyChar()=='s'){setVisible(true);}
        }
        public void keyTyped(KeyEvent e){}
    }

}

Answer 1

可见组件可以具有键盘焦点，并且可以接收键盘和其他输入事件，但是不可见组件不能具有焦点，也不能接收输入事件。使框架不可见时，它停止接收输入事件，包括所有test要添加的组件在内的所有子项也一样KeyListener。

要使此工作有效，您将必须具有可见的组件，并将键盘事件从该组件转发到不可见的框架。或者更好的是，invisibelFrame.setVisible(true)从您已经可见的组件中调用。

另外，您也许可以找到其他方式来触发显示框架。例如，带有上下文菜单的系统托盘组件是用于隐藏和显示应用程序框架的常见模式（对于某些用户，在此过程中会引起很多麻烦！）

看到

• Sun教程，如何使用系统托盘