Question

我正在尝试制作一个简单的计算器来练习图形（我是一个完整的GUI菜鸟）。我在使用Polyashenkos校准器和文本区域以及文本区域和按钮之间的空间后有不必要的空间时遇到一些问题。另外，我如何保持这种布局，但消除空间，并使底部3按钮更小。关于我正在做什么或如何做得更好的任何提示将非常感激。谢谢。

enter image description here

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

public class calculator {

    public static void main(String[] args) {
        // creates the JFrame(a window with decorations)
        JFrame frame = new JFrame("Calculator"); 
        // stops the program when window is closed
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        frame.setSize(377, 350);

        // the main panel of the JFrame, 
        // remembet you cant add content directly to JFrame
        JPanel content = new JPanel(new GridLayout(4, 0)); 
        // panel for the text field
        JPanel textarea = new JPanel(new GridLayout(4, 0)); 
        // panel for the buttons, 
        // GridLayout(int rows, int cols, int horiz_gap, int vert_gap)
        JPanel buttonarea = new JPanel(new GridLayout(4, 5, 2, 2)); 

        //  the panel for the bigger bottom buttons
        JPanel secondbuttonarea = new JPanel(new GridLayout(1, 1, 2, 2)); 
        // the panel for the text on top
        JPanel label = new JPanel(); 
        content.add(label);
        content.add(textarea);
        content.add(buttonarea);
        content.add(secondbuttonarea);

        JLabel words = new JLabel("Polyashenko's Calculator", JLabel.CENTER);
        label.add(words);

        JTextField enterhere = new JTextField("0.", JTextField.CENTER);
        // will set the curser of the text bar on right side
        enterhere.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT); 
        textarea.add(enterhere);

        // makes a button called b1 with text in it
        JButton b1 = new JButton("BkSP"); 
        // adds the backspace button to the buttonarea panel
        buttonarea.add(b1); 
        JButton b2 = new JButton("CE");
        buttonarea.add(b2);
        JButton b3 = new JButton("C");
        buttonarea.add(b3);
        JButton b4 = new JButton("/");
        buttonarea.add(b4);
        JButton b5 = new JButton("sqrt");
        buttonarea.add(b5);
        JButton b6 = new JButton("7");
        buttonarea.add(b6);
        JButton b7 = new JButton("8");
        buttonarea.add(b7);
        JButton b8 = new JButton("9");
        buttonarea.add(b8);
        JButton b9 = new JButton("*");
        buttonarea.add(b9);
        JButton b10 = new JButton("%");
        buttonarea.add(b10);
        JButton b11 = new JButton("4");
        buttonarea.add(b11);
        JButton b12 = new JButton("5");
        buttonarea.add(b12);
        JButton b13 = new JButton("6");
        buttonarea.add(b13);
        JButton b14 = new JButton("-");
        buttonarea.add(b14);
        JButton b15 = new JButton("1/x");
        buttonarea.add(b15);
        JButton b16 = new JButton("1");
        buttonarea.add(b16);
        JButton b17 = new JButton("2");
        buttonarea.add(b17);
        JButton b18 = new JButton("3");
        buttonarea.add(b18);
        JButton b19 = new JButton("+");
        buttonarea.add(b19);
        JButton b20 = new JButton("+/-");
        buttonarea.add(b20);

        JButton b21 = new JButton("0");
        secondbuttonarea.add(b21);
        JButton b22 = new JButton(".");
        secondbuttonarea.add(b22);
        JButton b23 = new JButton("=");
        secondbuttonarea.add(b23);

        // adds the buttonarea panel to the main panel
        frame.getContentPane().add(content); 
        // makes the window visible, put at end of program
        frame.setVisible(true); 
    }
}

Answer 1

Hovercraft Full Of Eels的一个课程（ - ：forums.sun.com： - ）

enter image description here

import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.*;
import javax.swing.*;

public class SciCalc {

    private static void createAndShowUI() {
        SciCalcGui gui = new SciCalcGui();
        SciCalcMenu menu = new SciCalcMenu(gui);
        JFrame frame = new JFrame("Calculator");
        frame.getContentPane().add(gui.getMainPanel());
        frame.setJMenuBar(menu.getJMenuBar());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                createAndShowUI();
            }
        });
    }

    private SciCalc() {
    }
}

class SciCalcGui {

    private static final String[][] STANDARD_BTN_TEXTS = {
        {"7", "8", "9", "/"}, {"4", "5", "6", "*"},
        {"1", "2", "3", "-"}, {"0", ".", "=", "+"}};
    private static final String[][] SCIENTIFIC_BTN_TEXTS = {
        {"sqrt", "1/x", "sin"}, {"%", "Exp", "cos"},
        {"x^y", "ln", "tan"}, {"x^2", "n!", "sec"}};
    private static final int GAP = 5;
    private static final Font BTN_FONT = new Font(Font.DIALOG, Font.BOLD, 20);
    private JPanel mainPanel = new JPanel();
    private JPanel sciPanel;
    private JTextField display = new JTextField();

    SciCalcGui() {
        display.setFont(BTN_FONT);
        JPanel standardPanel = createBtnPanel(STANDARD_BTN_TEXTS, "Standard");
        sciPanel = createBtnPanel(SCIENTIFIC_BTN_TEXTS, "Scientific");
        mainPanel.setLayout(new BorderLayout());
        mainPanel.setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
        mainPanel.add(standardPanel, BorderLayout.CENTER);
        mainPanel.add(sciPanel, BorderLayout.WEST);
        mainPanel.add(display, BorderLayout.NORTH);
        sciPanel.setVisible(false);
    }

    public void sciPanelSetVisible(boolean visible) {
        sciPanel.setVisible(visible);
        Window win = SwingUtilities.getWindowAncestor(mainPanel);
        win.pack();
    }

    public JPanel getMainPanel() {
        return mainPanel;
    }

    private JPanel createBtnPanel(String[][] texts, String title) {
        JPanel btnPanel = new JPanel();
        int rows = texts.length;
        int cols = texts[0].length;
        btnPanel.setLayout(new GridLayout(rows, cols, GAP, GAP));
        for (int row = 0; row < texts.length; row++) {
            for (int col = 0; col < texts[row].length; col++) {
                JButton btn = new JButton(texts[row][col]);
                btn.setFont(BTN_FONT);
                btnPanel.add(btn);
            }
        }
        btnPanel.setBorder(BorderFactory.createTitledBorder(title));
        return btnPanel;
    }
}

class SciCalcMenu {

    private static final String STANDARD = "Standard";
    private static final String SCIENTIFIC = "Scientific";
    private SciCalcGui gui;
    private JMenuBar menuBar = new JMenuBar();
    private JMenuItem standardView;
    private JMenuItem scientificView;

    SciCalcMenu(SciCalcGui gui) {
        this.gui = gui;
        standardView = new JMenuItem(STANDARD, KeyEvent.VK_T);
        scientificView = new JMenuItem(SCIENTIFIC, KeyEvent.VK_S);
        ViewAction viewAction = new ViewAction();
        standardView.addActionListener(viewAction);
        scientificView.addActionListener(viewAction);
        standardView.setEnabled(false);
        JMenu viewMenu = new JMenu("View");
        viewMenu.setMnemonic(KeyEvent.VK_V);
        viewMenu.add(standardView);
        viewMenu.add(scientificView);
        menuBar.add(new JMenu("Edit"));
        menuBar.add(viewMenu);
        menuBar.add(new JMenu("Help"));
    }

    public JMenuBar getJMenuBar() {
        return menuBar;
    }

    private class ViewAction implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            String command = e.getActionCommand();
            if (command.equals(STANDARD)) {
                gui.sciPanelSetVisible(false);
                standardView.setEnabled(false);
                scientificView.setEnabled(true);
            } else if (command.equals(SCIENTIFIC)) {
                gui.sciPanelSetVisible(true);
                standardView.setEnabled(true);
                scientificView.setEnabled(false);
            }
        }
    }
}

Answer 2

在这种情况下，GridLayout看起来不会很好。

内容展开以填充网格中的框。您只能最小程度地控制行和列之间的间距。

您可能需要更改布局以使其看起来像您想要的那样。 GridBagLayout具有所有控制权，但配置起来要困难得多。

有时，您可以使用BorderLayout和GridLayout嵌套面板，使其看起来合理。但它是Swing，这意味着它可以使用，但它变得非常难以让它看起来光滑。

我总是喜欢使用FlowLayout来确定/取消按钮。他们对我这样看起来最好，你可以将它们全部向左，向右或向中心推动。您的计算器按钮应该与GridLayout一起使用，但您不能轻易地使用高“Enter”按钮或宽“0”按钮。

例如，尝试使用垂直BoxLayout而不是4高1宽的网格。

如何在JFrame中排列多个面板

2 个答案: