如何使我的 Jbuttons / Jpanels 随 JFrame 调整大小？

Question

我用 Java 编写了这个计算器程序，我想为其添加更多功能。我希望程序做的是使用 JFrame 重新调整 JButtons / JPanels 的大小。这意味着当用户展开 JPanel 或全屏时，我希望按钮能够随 JFrame 适当调整大小。

public class Calculator implements ActionListener {

    JFrame frame; 
    JTextField textfield; 
    JButton[] numberButtons = new JButton[10];
    JButton[] functionButtons = new JButton[14];
    JButton addButton,subButton,mulButton,divButton; 
    JButton decButton,equButton,delButton,clrButton,negButton;
    JButton perButton,absButton,piButton,sqrButton,srootButton;
    JPanel panel; 
    
    Font myFont = new Font ("Helvetica",Font.BOLD,30);  
    
    double num1,num2,result = 0; 
    char operator;
    int height = 620;
    int width = 520;
    
    Calculator(){
          
        frame = new JFrame("Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(width, height);
        frame.setLayout(null);
        
        textfield = new JTextField();
        textfield.setBounds(50, 25, 400, 60);
        textfield.setFont(myFont);
        textfield.setEditable(false);
        textfield.setBorder(null);      
        
        addButton = new JButton(add); 
        addButton.setBackground(functionColor);
        
    
        subButton = new JButton(sub);
        subButton.setBackground(functionColor);
        
        mulButton = new JButton(mul);
        mulButton.setBackground(functionColor);
        
        divButton = new JButton(div);
        divButton.setBackground(functionColor);
        
        equButton = new JButton(equ); 
        equButton.setBackground(functionColor);
        
        
        decButton = new JButton("."); 
        decButton.setBackground (numberColor);
        decButton.setForeground (Color.WHITE);
        
        
        clrButton = new JButton("AC");
        clrButton.setBackground (top);
        clrButton.setForeground (Color.BLACK);
        
        
        negButton = new JButton("+/-");
        negButton.setBackground (top);
        negButton.setForeground (Color.BLACK);
        
        
 
        delButton = new JButton (delete);
        delButton.setBackground (top);
        delButton.setForeground (Color.BLACK);
        
        
        perButton = new JButton ("%");
        perButton.setBackground (top);
        perButton.setForeground (Color.BLACK);
        
        absButton = new JButton ("|x|");
        absButton.setBackground (top);
        absButton.setForeground (Color.BLACK);
        
        piButton = new JButton ("𝝅");
        piButton.setBackground (top);
        piButton.setForeground (Color.BLACK);
        
        sqrButton = new JButton ("x²");
        sqrButton.setBackground (top);
        sqrButton.setForeground (Color.BLACK);
        
        srootButton = new JButton ("√x");
        srootButton.setBackground (top);
        srootButton.setForeground (Color.BLACK);
        
        
        functionButtons[0] = addButton;
        functionButtons[1] = subButton;
        functionButtons[2] = mulButton;
        functionButtons[3] = divButton;
        functionButtons[4] = decButton;
        functionButtons[5] = equButton;
        functionButtons[6] = delButton;
        functionButtons[7] = clrButton;
        functionButtons[8] = negButton;
        functionButtons[9] = perButton;
        functionButtons[10]= piButton;
        functionButtons[11]= absButton;
        functionButtons[12]= sqrButton;
        functionButtons[13]= srootButton;
        
        
        for(int i = 0; i < 14; i++) {
            functionButtons[i].addActionListener(this);
            functionButtons[i].setFont(myFont);
            functionButtons[i].setFocusable(false);
        }
        
        for (int i = 0; i < 10; i++) {
            numberButtons[i] = new JButton(String.valueOf(i));
            numberButtons[i].addActionListener(this);
            numberButtons[i].setFont(myFont);
            numberButtons[i].setFocusable(false);   
        }
        
        JPanel secPan = new JPanel();
        secPan.setBounds(50,160,400,50);
        secPan.setLayout(new GridLayout(1,4,10,10));
        secPan.add(piButton);
        secPan.add(perButton);
        secPan.add(sqrButton);
        secPan.add(srootButton);
        frame.add(secPan);
        frame.setVisible(true);
        
        JPanel topPan = new JPanel();
        topPan.setBounds(50,100,400,50);
        topPan.setLayout(new GridLayout(1,4,10,10));
        topPan.add(negButton);
        topPan.add(absButton);
        topPan.add(clrButton);
        topPan.add(delButton);
        frame.add(topPan);
        frame.setVisible(true);
        
        
        panel = new JPanel();
        panel.setBounds(50, 220, 400, 300);
        panel.setLayout(new GridLayout(4,4,10,10));
        panel.add(numberButtons[7]);
        panel.add(numberButtons[8]);
        panel.add(numberButtons[9]);
        panel.add(mulButton);
        panel.add(numberButtons[4]);
        panel.add(numberButtons[5]);
        panel.add(numberButtons[6]);
        panel.add(subButton);
        panel.add(numberButtons[1]);
        panel.add(numberButtons[2]);
        panel.add(numberButtons[3]);
        panel.add(addButton);
        panel.add(numberButtons[0]);
        panel.add(decButton);
                panel.add(equButton);
        panel.add(divButton);
        
        for (int i = 0; i < numberButtons.length; i++) {
        numberButtons[i].setBackground(numberColor);
        numberButtons[i].setForeground(Color.WHITE);
        }
        frame.add(panel);
        frame.add(textfield);
        frame.setVisible(true);
    }
    

}

Answer 1

首先花时间阅读和探索在容器内布置组件

请注意，以下不是“最简单”的解决方案，而是最灵活的解决方案之一。您还可以结合使用

BorderLayout

和

GridLayout

来实现类似的效果。

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.Action;
import static javax.swing.Action.NAME;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;

public class Main {
    public static void main(String[] args) throws CloneNotSupportedException {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new CalculatorPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class CalculatorPane extends JPanel {
        public enum CalculatorAction {
            DIVIDE, MULTIPLY, SUBTRACT, ADD, EQUALS;

            public String getText() {
                switch (this) {
                    case DIVIDE: return "/";
                    case MULTIPLY: return "x";
                    case SUBTRACT: return "-";
                    case ADD: return "+";
                    case EQUALS: return "=";
                }
                return null;
            }
        }

        public CalculatorPane() {
            setBackground(Color.GRAY);
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 2;
            gbc.fill = GridBagConstraints.BOTH;
            gbc.weightx = 1;
            gbc.weighty = 1;

            int[][] values = new int[][] {
                { 7, 8, 9 },
                { 4, 5, 6 },
                { 1, 2, 3 },
            };
            for (int row = 0; row < values.length; row++) {
                gbc.gridx = 0;
                for (int col = 0; col < values[row].length; col++) {
                    add(makeNumericButton(values[row][col]), gbc);
                    gbc.gridx++;
                }
                gbc.gridy++;
            }
            gbc.gridx = 0;
            gbc.gridwidth = 3;
            add(makeNumericButton(0), gbc);

            gbc.gridx = 3;
            gbc.gridy = 1;

            add(makeActionButton(CalculatorAction.DIVIDE), gbc);

            gbc.gridy++;
            add(makeActionButton(CalculatorAction.MULTIPLY), gbc);

            gbc.gridy++;
            add(makeActionButton(CalculatorAction.SUBTRACT), gbc);

            gbc.gridy++;
            add(makeActionButton(CalculatorAction.ADD), gbc);

            gbc.gridy++;
            add(makeActionButton(CalculatorAction.EQUALS), gbc);

            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            JTextField field = new JTextField(5);
            field.setBackground(Color.DARK_GRAY);
            field.setForeground(Color.WHITE);
            field.setBorder(null);
            field.setHorizontalAlignment(JTextField.TRAILING);
            field.setFont(field.getFont().deriveFont(48f));
            add(field, gbc);
        }

        protected JButton makeButton(Action action) {
            JButton button = new JButton(action);
            button.setContentAreaFilled(false);
            button.setOpaque(true);
            button.setBorder(new CompoundBorder(new LineBorder(Color.BLACK), new EmptyBorder(16, 16, 16, 16)));
            return button;
        }

        protected JButton makeNumericButton(int value) {
            JButton button = makeButton(new NumericAction(value));
            button.setBackground(Color.DARK_GRAY);
            button.setForeground(Color.WHITE);
            button.setBorder(new CompoundBorder(new LineBorder(Color.BLACK), new EmptyBorder(16, 16, 16, 16)));
            return button;
        }

        protected JButton makeActionButton(CalculatorAction value) {
            JButton button = makeButton(new OperationAction(value));
            button.setBackground(Color.ORANGE);
            button.setForeground(Color.WHITE);
            button.setBorder(new CompoundBorder(new LineBorder(Color.BLACK), new EmptyBorder(16, 16, 16, 16)));
            return button;
        }

        protected class NumericAction extends AbstractAction {
            private int value;

            public NumericAction(int value) {
                this.value = value;
                putValue(NAME, Integer.toString(value));
            }

            @Override
            public void actionPerformed(ActionEvent e) {
            }
        }

        protected class OperationAction extends AbstractAction {
            private CalculatorAction value;

            public OperationAction(CalculatorAction value) {
                this.value = value;
                putValue(NAME, value.getText());
            }

            @Override
            public void actionPerformed(ActionEvent e) {
            }
        }
    }
}