12

当鼠标单击该文本字段时，我需要使该程序清除该文本字段中的文本。我尝试了一些事情，但没有一个对我有用。

这是完整的代码：

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

    }
}
4

7 回答 7

27

TL;博士

无论如何，注册MouseAdapter和覆盖mouseClicked对我有用，

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();
            }
        });
    }
}

我希望这个例子能让你朝着正确的方向开始！

于 2012-04-13T00:03:24.380 回答
15

您可以简单地将 a 添加FocusListener到文本字段。

 final JTextField textField = new JTextField("Enter text here...");
    textField.addFocusListener(new FocusListener(){
        @Override
        public void focusGained(FocusEvent e){
            textField.setText("");
        }
    });
于 2012-04-13T00:11:41.930 回答
3

这对我有用。当然，点击的时候文字会被清空，你可以输入新的文字。要通过单击再次清除文本，文本字段必须失去焦点，然后从鼠标重新获得焦点。我不完全确定您在这里寻找什么。 

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.JFrame;
import javax.swing.JTextField;

public class ClickTextField extends JTextField implements MouseListener{

public static void main(String[] args) {
    new ClickTextField();
}

public ClickTextField() {
    addMouseListener(this);

    JFrame J = new JFrame();
    J.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    J.setSize(100,100);
    J.getContentPane().add(this);
    setText("Texty text...");
    J.show();
}

@Override
public void mouseClicked(MouseEvent e) {

    setText("");

}

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

}

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

}

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

}

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

}

}
于 2012-04-13T00:09:12.343 回答
3

是清除“提示”文本吗？

我想这就是你想要做的......

textField.addMouseListener(new MouseAdapter())
    {
        public void mouseClicked(MouseEvent e)
        {
            if(textField.getText().equals("Default Text"))
            {
                textField.setText("");
                repaint();
                revalidate();
            }           
        }
    });
于 2013-06-29T17:39:15.707 回答
0

我也必须这样做。我所做的只是制作一个定制的JTextField. 就像是：

import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.JTextField;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

@SuppressWarnings("serial")
public class InputField extends JTextField implements MouseListener,ActionListener
{
public InputField(String text) 
{
    super(text);
    super.setHorizontalAlignment(RIGHT);
    super.addMouseListener(this);
}

@Override
public void mouseClicked(MouseEvent e) 
{
    // TODO Auto-generated method stub
    if (getText().equals("0.0"))
    {
        setText("");
    }
}

@Override
public void mouseEntered(MouseEvent e) 
{

}

@Override
public void mouseExited(MouseEvent e)
{

}

@Override
public void mousePressed(MouseEvent e) {
    maybeShowPopup(e);
    // if the mouse is pressed and "0.0" is the text, we erase the text
    if (getText().equals("0.0"))
    {
        setText("");
    }
}

@Override
public void mouseReleased(MouseEvent e) 
{
    maybeShowPopup(e);
}

private void maybeShowPopup(MouseEvent event)
{
    //if the user clicked the right mouse button
    if (javax.swing.SwingUtilities.isRightMouseButton(event))
    {
        //create (and show) the popup
        createPopup().show(event.getComponent(), event.getX(), event.getY());
    }
}

private JPopupMenu createPopup()
{
    JPopupMenu popupMenu = new JPopupMenu();
    //add the clearTextOption to the JPopupMenu
    JMenuItem clearTextOption = new JMenuItem("Clear text");
    clearTextOption.addActionListener(this);
    popupMenu.add(clearTextOption);
    return popupMenu;
}

@Override
public void actionPerformed(ActionEvent arg0) {
    //clear the TextField
    setText("");
}

} //end custom TextField

在这个自定义的 TextField 中，我只是使用了MouseListener. 定制一个的优点是：

  1. 我可以让它直接实现 MouseListener （而不必使用一些令人困惑的匿名内部类）
  2. 我可以进行大量自定义（包括用户右键单击 TextField 并从 PopupMenu 中选择项目的选项。//我目前正在研究用户复制、粘贴和拖放的选项。
  3. 我可以做到这一切，而不用在主.java文件中塞满额外的代码，这些额外的代码会在以后挖掘更多的东西。虽然MikeWarren.getAnswer(this) extends richard.getAnswer(this)，我想我会更详细一点，并展示一些我在我的一个程序中实际使用的代码。
于 2013-07-05T15:15:15.107 回答
0

公共 JTextField 用户输入；

在执行文本之后：

userInput.setText(""); // 空的

这应该做。

于 2016-04-20T03:15:09.467 回答
0 
 jTextField2.addMouseListener(new MouseListener() {
            @Override
            public void mouseClicked(MouseEvent e) {
                if (e.getButton()==1) {
                    jTextField2.setText("");
                }//3 = for right click 
                //2 for middlemouse
            }

            @Override
            public void mousePressed(MouseEvent e) {

            }

            @Override
            public void mouseReleased(MouseEvent e) {

            }

            @Override
            public void mouseEntered(MouseEvent e) {

            }

            @Override
            public void mouseExited(MouseEvent e) {

            }
        });

您也可以尝试使用这种方法。

于 2016-04-22T14:53:06.557 回答