Question

我有一个带有“输入鼠标”文字的JLabel。一旦用户在其上输入鼠标，我就会想要出现一个JTextField，这样用户就可以搜索一些东西。如果删除鼠标，则必须再次显示先前的JLabel。我用：

import java.awt.CardLayout;

import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class ML extends JFrame {
    private static final long serialVersionUID = 1L;

    public ML() {
        GridLayout gl = new GridLayout(1, 2);
        setLayout(gl);

        JPanel jp = new JPanel();
        CardLayout cl = new CardLayout();
        jp.setLayout(cl);

        JPanel jp1 = new JPanel();
        JLabel jl = new JLabel("Enter mouse!");
        jp1.add(jl);

        JPanel jp2 = new JPanel();
        JTextField jtf = new JTextField(20);
        jp2.add(jtf);

        jp.add(jp1, "1");
        jp.add(jp2, "2");
        cl.show(jp, "1");


        jp.addMouseListener(new MouseAdapter()
        {
            public void mouseEntered(MouseEvent evt)
            {
                cl.show(jp, "2");
            }
            public void mouseExited(MouseEvent evt)
            {
                cl.show(jp, "1");
            }
        });

        add(jp);

        this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        this.pack();
        this.setVisible(true);

     }


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

一切都运行得很好但是当我将鼠标悬停在JLabel“Enter mouse”上时，它在这个和JTextField之间有些错误/闪烁。为什么会这样，我该怎么做才能解决它？ TY

Answer 1

这是因为当显示JTextField时，会立即调用mouseExited()方法。然后当然再次显示JLabel，当你继续移动鼠标时，它会循环。

以下作品：

    jl.addMouseListener(new MouseAdapter() {
        public void mouseEntered(MouseEvent evt) {
            cl.show(jp, "2");
        }
    });

    jtf.addMouseListener(new MouseAdapter() {
        public void mouseExited(MouseEvent evt) {
            cl.show(jp, "1");
        }
    });

Answer 2

即使它没有出现故障，它也不会起作用，因为文本字段大于标签，并且您只将监听器添加到标签中。导致故障是因为仅显示了文本字段，因此它会触发标签上的mouseExited事件。要解决此问题，您需要标签上的mouseEntered事件，但文本字段上的mouseExited事件仅。

import java.awt.CardLayout;

import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class ML extends JFrame {
    private static final long serialVersionUID = 1L;

    public ML() {
        GridLayout gl = new GridLayout(1, 2);
        setLayout(gl);

        JPanel jp = new JPanel();
        CardLayout cl = new CardLayout();
        jp.setLayout(cl);

        JPanel jp1 = new JPanel();
        JLabel jl = new JLabel("Enter mouse!");
        jp1.add(jl);

        JPanel jp2 = new JPanel();
        JTextField jtf = new JTextField(20);
        jp2.add(jtf);

        jp.add(jp1, "1");
        jp.add(jp2, "2");
        cl.show(jp, "1");

        jl.addMouseListener(new MouseAdapter() {
            public void mouseEntered(MouseEvent evt) {
                cl.show(jp, "2");
            }
        });

        jtf.addMouseListener(new MouseAdapter() {
            public void mouseExited(MouseEvent evt) {
                cl.show(jp, "1");
            }
        });

        add(jp);

        this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        this.pack();
        this.setVisible(true);

    }

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

JLabel - On Mouse输入对JTextField的更改

2 个答案: