如何在鼠标单击JTextField时清除JTextField [英] How to clear JTextField when mouse clicks the JTextField

问题描述

当鼠标在该文本字段中单击时，我需要使该程序清除文本字段中的文本。我尝试过一些东西，但是没有一个能为我工作。

这是完整的代码：

'pre> 公共类TimerClassPanel延伸的JFrame实现的MouseListener {

公共TimerClassPanel（）{
的setTitle（ 定时器类）;
setSize（WIDTH，HEIGHT）;

timer = new Timer（DELAY，new TimerEventHandler（））;

pane = getContentPane（）;
pane.setLayout（null）;

int r =（int）（9.0 * Math.random（））+ 1;
String str2 = Integer.toString（r）;

label = new JLabel（str2，SwingConstants.CENTER）;
label.setSize（150,30）;
label.setLocation（0,0）;

textField = new JTextField（）;
textField.setSize（150,30）;
textField.setLocation（150,0）;

startB =新JButton（开始）;
startbh = new StartButtonHandler（）;
startB.addActionListener（startbh）;
startB.setSize（100,30）;
startB.setLocation（0,30）;

stopB = new JButton（Stop）;
stopbh = new StopButtonHandler（）;
stopB.addActionListener（stopbh）;
stopB.setSize（100,30）;
stopB.setLocation（100,30）;

exitB =新JButton（退出）;
ebHandler = new ExitButtonHandler（）;
exitB.addActionListener（ebHandler）;
exitB.setSize（100,30）;
exitB.setLocation（200,30）;

pane.add（label）;

pane.add（textField）;
pane.add（startB）;
pane.add（stopB）;
pane.add（exitB）;

timer = new Timer（DELAY，new TimerEventHandler（））;

setVisible（true）;
setDefaultCloseOperation（EXIT_ON_CLOSE）;
}

私人类TimerEventHandler实现的ActionListener {
公共无效的actionPerformed（ActionEvent的发送）{
INT R =（int）的（9.0 *的Math.random（）） + 1;
String str = Integer.toString（r）;
currentNum =;
currentNum = str;
label.setText（str）;
repaint（）;
}
}

公共类StartButtonHandler实现ActionListener {
public void actionPerformed（ActionEvent e）{
timer.start（）;
}
}

公共类StopButtonHandler实现ActionListener {
public void actionPerformed（ActionEvent e）{
timer.stop（）;
}
}

私有类ExitButtonHandler实现ActionListener {
public void actionPerformed（ActionEvent e）{
System.exit（0）;
}
}

public static void main（String [] args）{
TimerClassPanel timerPanel = new TimerClassPanel（）;
JOptionPane.showMessageDialog（null，键入你的猜测（在1-9之间为int）+
在字段中然后按'ENTER'）;
}

@Override
public void mouseClicked（MouseEvent e）{
if（e.getX（）> 150&& e.getX（） < 300&& e.getY（）> 0&& e.getY（）< 30）
{
textField.setText（）;
repaint（）;
}
}

@Override
public void mouseEntered（MouseEvent arg0）{
// TODO自动生成的方法stub

}

@Override
public void mouseExited（MouseEvent arg0）{
// TODO自动生成方法存根

}

@Override
public void mousePressed（MouseEvent arg0）{
// TODO自动生成的方法stub

}

@Override
public void mouseReleased（MouseEvent arg0）{
// TODO自动生成方法存根

}
}


解决方案

TL; DR

无论如何，注册 MouseAdapter 并覆盖 mouseClicked 为我工作，

  import java.awt.FlowLayout; 
 import java.awt.event.MouseAdapter; 
 import java.awt.event.MouseEvent; 
 import javax.swing.JFrame; 
 import javax.swing.JTextField; 
 import javax.swing.SwingUtilities; 
 
 public class ClickAndClearDemo {
 private static void createAndShowGUI（）{
 JFrame frame = new JFrame（）; 
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 frame.setLayout（new FlowLayout（FlowLayout.CENTER，20,20））; 
 
 final JTextField textField = new JTextField（在这里输入文字......）; 
 textField.addMouseListener（新MouseAdapter（）{
 @覆盖
公共无效的mouseClicked（的MouseEvent E）{
 textField.setText（ ）; 
} 
}）; 
 
 frame.add（textField）; 
 frame.pack（）; 
 frame.setVisible（true）; 
} 
 
 public static void main（String [] args）{
 SwingUtilities.invokeLater（new Runnable（）{
 @Override 
 public void run （）{
 createAndShowGUI（）; 
} 
}）; 
} 
} 
  

我希望这个例子让你开始朝着正确的方向前进！

I need to make this program clear the text from the text field when the mouse clicks in that text field. I have tried a few things, but none of them have yet to work for me.

Here is the code in its entirety:

public class TimerClassPanel extends JFrame implements MouseListener{

    public TimerClassPanel(){
        setTitle("Timer Class");
        setSize(WIDTH, HEIGHT);

        timer = new Timer(DELAY, new TimerEventHandler());

        pane = getContentPane();
        pane.setLayout(null);

        int r = (int)(9.0 * Math.random()) + 1;
        String str2 = Integer.toString(r);

        label = new JLabel(str2, SwingConstants.CENTER);
        label.setSize(150,30);
        label.setLocation(0,0);

        textField = new JTextField();
        textField.setSize(150,30);
        textField.setLocation(150,0);

        startB = new JButton("Start");
        startbh = new StartButtonHandler();
        startB.addActionListener(startbh);
        startB.setSize(100,30);
        startB.setLocation(0,30);

        stopB = new JButton("Stop");
        stopbh = new StopButtonHandler();
        stopB.addActionListener(stopbh);
        stopB.setSize(100,30);
        stopB.setLocation(100,30);

        exitB = new JButton("Exit");
        ebHandler = new ExitButtonHandler();
        exitB.addActionListener(ebHandler);
        exitB.setSize(100,30);
        exitB.setLocation(200,30);      

        pane.add(label);

        pane.add(textField);
        pane.add(startB);
        pane.add(stopB);
        pane.add(exitB);

        timer = new Timer(DELAY, new TimerEventHandler());

        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    private class TimerEventHandler implements ActionListener{
        public void actionPerformed(ActionEvent e){
            int r = (int)(9.0 * Math.random()) + 1;
            String str = Integer.toString(r);
            currentNum = "";
            currentNum = str;
            label.setText(str);
            repaint();
        }
    }

    public class StartButtonHandler implements ActionListener{
        public void actionPerformed(ActionEvent e){
            timer.start();
        }
    }

    public class StopButtonHandler implements ActionListener{
        public void actionPerformed(ActionEvent e){
            timer.stop();
        }
    }

    private class ExitButtonHandler implements ActionListener{
        public void actionPerformed(ActionEvent e){
            System.exit(0);
        }
    }

    public static void main(String[] args){
        TimerClassPanel timerPanel = new TimerClassPanel();
        JOptionPane.showMessageDialog(null, "Type your guess (int between 1-9)" +
                " in the field then press 'ENTER'");
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        if( e.getX() > 150 && e.getX() < 300 && e.getY() > 0 && e.getY() < 30)
        {   
            textField.setText("");
            repaint();
        }
    }

    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mousePressed(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
}

解决方案

TL;DR

Anyway, registering a MouseAdapter and overriding mouseClicked worked for me,

import java.awt.FlowLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class ClickAndClearDemo {
    private static void createAndShowGUI(){
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLayout(new FlowLayout(FlowLayout.CENTER, 20, 20));

        final JTextField textField = new JTextField("Enter text here...");
        textField.addMouseListener(new MouseAdapter(){
            @Override
            public void mouseClicked(MouseEvent e){
                textField.setText("");
            }
        });

        frame.add(textField);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

I hope this example gets you started in the right direction!

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