java - 如何在虚拟键盘上使字母彼此间隔

Question

我最近才学会如何使用 JButton、JFrame 等，并正在尝试制作键盘。到目前为止，当我单击字母时，会出现 JLabel，但我很难让它们彼此相邻，因为它们都出现在彼此之上。我想知道是否有人可以帮助我解决这个问题。我知道我的代码并不理想，但虽然我仍然缺乏经验，但这是目前我知道如何做到这一点的唯一方法。这是到目前为止我的代码(不包括用于运行整个代码的“Run”方法):

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

public class Frame extends JFrame {

    JButton a;
    JButton b;
    JButton c;
    JButton d;
    JButton e;
    JButton f;
    JButton g;
    JButton h;
    JButton i;
    JButton j;
    JButton k;
    JButton l;
    JButton m;
    JButton n;
    JButton o;
    JButton p;
    JButton q;
    JButton r;
    JButton s;
    JButton t;
    JButton u;
    JButton v;
    JButton w;
    JButton x;
    JButton y;
    JButton z;
    JButton space;
    JPanel panel;

    public Frame() {

        panel = new JPanel();
        panel.setBackground(Color.WHITE);
        panel.setLayout(null);
        add(panel);

        a = new JButton("A");
        a.setBounds(100, 0, 50, 37);
        b = new JButton("B");
        b.setBounds(200, 0, 50, 37);
        c = new JButton("C");
        c.setBounds(300, 0, 50, 37);
        d = new JButton("D");
        d.setBounds(400, 0, 50, 37);
        e = new JButton("E");
        e.setBounds(500, 0, 50, 37);
        f = new JButton("F");
        f.setBounds(600, 0, 50, 37);
        g = new JButton("G");
        g.setBounds(100, 50, 50, 37);
        h = new JButton("H");
        h.setBounds(200, 50, 50, 37);
        i = new JButton("I");
        i.setBounds(300, 50, 50, 37);
        j = new JButton("J");
        j.setBounds(400, 50, 50, 37);
        k = new JButton("K");
        k.setBounds(500, 50, 50, 37);
        l = new JButton("L");
        l.setBounds(600, 50, 50, 37);
        m = new JButton("M");
        m.setBounds(100, 100, 50, 37);
        n = new JButton("N");
        n.setBounds(200, 100, 50, 37);
        o = new JButton("O");
        o.setBounds(300, 100, 50, 37);
        p = new JButton("P");
        p.setBounds(400, 100, 50, 37);
        q = new JButton("Q");
        q.setBounds(500, 100, 50, 37);
        r = new JButton("R");
        r.setBounds(600, 100, 50, 37);
        s = new JButton("S");
        s.setBounds(100, 150, 50, 37);
        t = new JButton("T");
        t.setBounds(200, 150, 50, 37);
        u = new JButton("U");
        u.setBounds(300, 150, 50, 37);
        v = new JButton("V");
        v.setBounds(400, 150, 50, 37);
        w = new JButton("W");
        w.setBounds(500, 150, 50, 37);
        x = new JButton("X");
        x.setBounds(600, 150, 50, 37);
        y = new JButton("Y");
        y.setBounds(100, 200, 50, 37);
        z = new JButton("Z");
        z.setBounds(200, 200, 50, 37);

        space = new JButton("SPACE");
        space.setBounds(300, 200, 100, 37);

        panel.add(a);
        panel.add(b);
        panel.add(c);
        panel.add(d);
        panel.add(e);
        panel.add(f);
        panel.add(g);
        panel.add(h);
        panel.add(i);
        panel.add(j);
        panel.add(k);
        panel.add(l);
        panel.add(m);
        panel.add(n);
        panel.add(o);
        panel.add(p);
        panel.add(q);
        panel.add(r);
        panel.add(s);
        panel.add(t);
        panel.add(u);
        panel.add(v);
        panel.add(w);
        panel.add(x);
        panel.add(y);
        panel.add(z);
        panel.add(space);

        Handler handler = new Handler();
        a.addActionListener(handler);
        b.addActionListener(handler);
        c.addActionListener(handler);
        d.addActionListener(handler);
        e.addActionListener(handler);
        f.addActionListener(handler);
        g.addActionListener(handler);
        h.addActionListener(handler);
        i.addActionListener(handler);
        j.addActionListener(handler);
        k.addActionListener(handler);
        l.addActionListener(handler);
        m.addActionListener(handler);
        n.addActionListener(handler);
        o.addActionListener(handler);
        p.addActionListener(handler);
        q.addActionListener(handler);
        r.addActionListener(handler);
        s.addActionListener(handler);
        t.addActionListener(handler);
        u.addActionListener(handler);
        v.addActionListener(handler);
        w.addActionListener(handler);
        x.addActionListener(handler);
        y.addActionListener(handler);
        z.addActionListener(handler);

        space.addActionListener(handler);
    }

    class Handler implements ActionListener {
        public void actionPerformed(ActionEvent event) {
            if (event.getSource() == a) {
                JLabel text = new JLabel("A");
                text.setBounds(100, 250, 100, 100);
                text.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == b) {
                JLabel text2 = new JLabel("B");
                text2.setBounds(100, 250, 100, 100);
                text2.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text2);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == c) {
                JLabel text3 = new JLabel("C");
                text3.setBounds(100, 250, 100, 100);
                text3.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text3);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == d) {
                JLabel text4 = new JLabel("D");
                text4.setBounds(100, 250, 100, 100);
                text4.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text4);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == e) {
                JLabel text5 = new JLabel("E");
                text5.setBounds(100, 250, 100, 100);
                text5.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text5);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == f) {
                JLabel text6 = new JLabel("F");
                text6.setBounds(100, 250, 100, 100);
                text6.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text6);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == g) {
                JLabel text7 = new JLabel("G");
                text7.setBounds(100, 250, 100, 100);
                text7.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text7);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == h) {
                JLabel text8 = new JLabel("H");
                text8.setBounds(100, 250, 100, 100);
                text8.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text8);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == i) {
                JLabel text9 = new JLabel("I");
                text9.setBounds(100, 250, 100, 100);
                text9.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text9);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == j) {
                JLabel text10 = new JLabel("J");
                text10.setBounds(100, 250, 100, 100);
                text10.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text10);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == k) {
                JLabel text11 = new JLabel("K");
                text11.setBounds(100, 250, 100, 100);
                text11.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text11);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == l) {
                JLabel text12 = new JLabel("L");
                text12.setBounds(100, 250, 100, 100);
                text12.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text12);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == m) {
                JLabel text13 = new JLabel("M");
                text13.setBounds(100, 250, 100, 100);
                text13.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text13);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == n) {
                JLabel text14 = new JLabel("N");
                text14.setBounds(100, 250, 100, 100);
                text14.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text14);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == o) {
                JLabel text15 = new JLabel("O");
                text15.setBounds(100, 250, 100, 100);
                text15.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text15);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == p) {
                JLabel text16 = new JLabel("P");
                text16.setBounds(100, 250, 100, 100);
                text16.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text16);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == q) {
                JLabel text17 = new JLabel("Q");
                text17.setBounds(100, 250, 100, 100);
                text17.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text17);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == r) {
                JLabel text18 = new JLabel("R");
                text18.setBounds(100, 250, 100, 100);
                text18.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text18);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == s) {
                JLabel text19 = new JLabel("S");
                text19.setBounds(100, 250, 100, 100);
                text19.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text19);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == t) {
                JLabel text20 = new JLabel("T");
                text20.setBounds(100, 250, 100, 100);
                text20.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text20);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == u) {
                JLabel text21 = new JLabel("U");
                text21.setBounds(100, 250, 100, 100);
                text21.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text21);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == v) {
                JLabel text22 = new JLabel("V");
                text22.setBounds(100, 250, 100, 100);
                text22.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text22);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == w) {
                JLabel text23 = new JLabel("W");
                text23.setBounds(100, 250, 100, 100);
                text23.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text23);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == x) {
                JLabel text24 = new JLabel("X");
                text24.setBounds(100, 250, 100, 100);
                text24.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text24);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == y) {
                JLabel text25 = new JLabel("Y");
                text25.setBounds(100, 250, 100, 100);
                text25.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text25);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == z) {
                JLabel text26 = new JLabel("Z");
                text26.setBounds(100, 250, 100, 100);
                text26.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text26);
                panel.repaint();
                panel.revalidate();
            }
            if (event.getSource() == space) {
                JLabel text27 = new JLabel(" ");
                text27.setBounds(100, 250, 100, 100);
                text27.setFont(new Font("Serif", Font.BOLD, 50));
                panel.add(text27);
                panel.repaint();
                panel.revalidate();
            }
        }
    }
}

Answer 1

您的代码中有几个错误:

1. 您正在调用 Frame给您JFrame ，由于 AWT Frame ，这可能会令人困惑。类。

2. 您正在扩展 JFrame ，但你不会在任何地方改变它的行为，所以没有必要。基于JPanel构建您的GUI未开启 JFrame s。请参阅:Extends JFrame vs. creating it inside the program了解更多相关信息。

3. 您正在为每个字母创建一个新变量。您可以将其更改为数组并使用 for循环并迭代它们，这样您的代码就更容易阅读、维护和理解。

4. 也许您的代码中最重要和最危险的错误:您正在使用 null-layout并手动定位每个组件，这可能会导致您在不同的操作系统/PLAF/屏幕尺寸和分辨率中出现奇怪的输出!，请参阅this example快速检查为什么不鼓励使用 null-layout构建您的 GUI。请参阅Null layout is evil和 Why is it frowned upon to use a null layout in Swing?有关此的更多信息。要纠正它，请正确使用各种Layout managers并与其他人一起使用它们并省略对 .setBounds(...) 的调用.

5. 不要将对象与 == 进行比较:if (event.getSource() == a) {应该是if (event.getSource().equals(a)) {相反或如下面的代码所示 ife.getActionCommand().equals("TextInsideYourJButton") { ... }

6. 最后但同样重要的是，为变量使用有意义的名称:a如果有人第一次阅读您的代码，他/她将很难确定a是 JButton !关注 Java naming conventions .

现在，我编写的代码是在您发布图像链接之前编写的，因此 GUI 可能会有所不同:

import java.awt.Component;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;

public class VirtualKeyBoard {
    private JFrame frame;
    private JPanel mainPane;
    private GridBagConstraints c;
    private JLabel label;

    private static final String[] NUMBERS = new String[] {"1", "2", "3", "4", "5", "6", "7", "8", "9", "0"};
    private static final String[] FIRST_ROW_LETTERS = new String[] {"Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P"};
    private static final String[] SECOND_ROW_LETTERS = new String[] {"A", "S", "D", "F", "G", "H", "J", "K", "L"};
    private static final String[] THIRD_ROW_LETTERS = new String[] {"Z", "X", "C", "V", "B", "N", "M"};

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new VirtualKeyBoard()::createAndShowGui);
    }

    private void createAndShowGui() {
        frame = new JFrame();
        mainPane = new JPanel();
        mainPane.setLayout(new GridLayout(6, 1, 5, 5));

        label = new JLabel("");
        label.setHorizontalAlignment(SwingConstants.CENTER);

        c = new GridBagConstraints();
        c.insets = new Insets(5, 5, 5, 5);
        c.fill = GridBagConstraints.BOTH;

        mainPane.add(addRow(NUMBERS));
        mainPane.add(addRow(FIRST_ROW_LETTERS));
        mainPane.add(addRow(SECOND_ROW_LETTERS));
        mainPane.add(addRow(THIRD_ROW_LETTERS));

        JButton spaceButton = new JButton("SPACE");
        spaceButton.addActionListener(listener);

        mainPane.add(spaceButton);
        mainPane.add(label);

        frame.add(mainPane);
        frame.pack();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private ActionListener listener = e -> {
        if (e.getActionCommand().equals("SPACE")) {
            label.setText("");
        } else {
            label.setText(e.getActionCommand());
        }
    };

    private JPanel addRow(String[] values) {
        JPanel pane = new JPanel();
        pane.setLayout(new GridBagLayout());

        for (String s : values) {
            c.gridx++;
            JButton button = new JButton(s);
            button.addActionListener(listener);
            pane.add(button, c);
        }

        return pane;
    }
}

上面的代码产生这个输出。正如你所看到的，我从未使用过 .setBounds() ，但我组合了 2 个布局管理器，例如 GridLayout和GridBagLayout我使用了一个 ActionListener对于我们所有人JButton刚刚设置了 ActionCommand值 JLabel单击时。

要生成与您在图像中发布的输出类似的输出:

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;

public class SimpleVirtualKeyBoard {
    private JFrame frame;
    private JPanel pane;
    private JButton[] buttons;
    private JButton spaceButton;
    private JLabel label;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new SimpleVirtualKeyBoard()::createAndShowGui);
    }

    private void createAndShowGui() {
        frame = new JFrame(getClass().getSimpleName());

        pane = new JPanel();
        pane.setLayout(new GridLayout(0, 6, 10, 10));

        String[] letters = new String[26];

        spaceButton = new JButton("SPACE");
        spaceButton.addActionListener(listener);

        label = new JLabel(" ");
        label.setHorizontalAlignment(SwingConstants.CENTER);

        for (char i = 'A'; i <= 'Z'; i++) {
            letters[i - 'A'] = String.valueOf(i); //We fill our alphabet array
            System.out.println(letters[i - 'A']);
        }

        buttons = new JButton[26];

        for (int i = 0; i < buttons.length; i++) {
            buttons[i] = new JButton(letters[i]);
            buttons[i].addActionListener(listener);

            pane.add(buttons[i]);
        }

        pane.add(spaceButton);

        frame.add(pane);
        frame.add(label, BorderLayout.SOUTH);

        frame.pack();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private ActionListener listener = e -> {
        label.setText(e.getActionCommand());
    };
}

产生以下输出:

你可以在上面的代码中看到我再次没有使用 .setBounds()在这种情况下，我使用了一个 LayoutManger这是GridLayout