关于java：如何根据其大小更改JButton的字体大小？

How to change font size of JButton according to its size?

我有一个Java应用程序-计算器。我想通过调整应用程序窗口的大小来动态调整按钮的字体大小。如何执行呢？

我的想法是使用ComponentEvents。我有应用程序窗口的初始大小和初始字体的大小。我想根据按钮的大小更改字体大小，受窗口大小更改的影响。问题是如何在替代方法中使用[初始窗口大小] / [初始字体大小]的比值？每种字体的比率都不同。

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

public class Main extends JFrame {
public Main() {
super("Test");

JPanel cPane = (JPanel) getContentPane();
cPane.setLayout(new BorderLayout());
MyButton sampleButton = new MyButton("Sample text");
sampleButton.setFont(new Font("Sans Serif", Font.PLAIN, 20));

MyButton a, b, c, d;
a = new MyButton("a");
b = new MyButton("b");
c = new MyButton("c");
d = new MyButton("d");

cPane.add(a, BorderLayout.PAGE_START);
cPane.add(b, BorderLayout.PAGE_END);
cPane.add(c, BorderLayout.LINE_START);
cPane.add(d, BorderLayout.LINE_END);

cPane.add(sampleButton, BorderLayout.CENTER);
setSize(300, 200);
setResizable(true);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setVisible(true);
}

public static void main(String... args) {
new Main();
}

class MyButton extends JButton implements ComponentListener {
public MyButton(String title) {
super(title);
}

@Override
public void componentResized(ComponentEvent e) {
//resizing font
}

@Override
public void componentMoved(ComponentEvent e) {

}

@Override
public void componentShown(ComponentEvent e) {

}

@Override
public void componentHidden(ComponentEvent e) {

}
}
}

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使用GlyphVector查看如何使用此代码来确定适合的最大Font。

除非将帧设置为可见并添加ComponentListener之间没有延迟，否则GUI有点不稳定。我通过使用单发Swing Timer延迟添加侦听器来解决此问题。
Is基于Calculet，它是使用ScriptEngine的功能全面(如果简单的话)的计算器。

Initial

Bigger

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import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.util.ArrayList;
import javax.script.*;
import javax.swing.border.Border;

class SwingCalculator implements ActionListener, KeyListener {

JTextField io;
ScriptEngine engine;
ArrayList<JButton> controls;
final BufferedImage textImage = new BufferedImage(
100, 100,
BufferedImage.TYPE_INT_ARGB);

public int getMaxFontSizeForControls() {
Graphics2D g = textImage.createGraphics();
FontRenderContext frc = g.getFontRenderContext();
int maxSize = 500;
for (JButton b : controls) {
// skip the = button..
if (!b.getText().equals("=")) {
int max = getMaxFontSizeForControl(b, frc);
if (maxSize > max) {
maxSize = max;
}
}
}
g.dispose();
return maxSize;
}

public int getMaxFontSizeForControl(JButton button, FontRenderContext frc) {
Rectangle r = button.getBounds();
Insets m = button.getMargin();
Insets i = button.getBorder().getBorderInsets(button);
Rectangle viewableArea = new Rectangle(
r.width -
(m.right + m.left + i.left + i.right),
r.height -
(m.top + m.bottom + i.top + i.bottom)
);
Font font = button.getFont();
int size = 1;
boolean tooBig = false;
while (!tooBig) {
Font f = font.deriveFont((float) size);
GlyphVector gv = f.createGlyphVector(frc, button.getText());
Rectangle2D box = gv.getVisualBounds();
if (box.getHeight() > viewableArea.getHeight()
|| box.getWidth() > viewableArea.getWidth()) {
tooBig = true;
size--;
}
size++;
}
return size;
}

SwingCalculator() {
// obtain a reference to the JS engine
engine = new ScriptEngineManager().getEngineByExtension("js");

JPanel gui = new JPanel(new BorderLayout(2, 2));
controls = new ArrayList<JButton>();

JPanel text = new JPanel(new GridLayout(0, 1, 3, 3));
gui.add(text, BorderLayout.NORTH);
io = new JTextField(15);
Font font = io.getFont();
font = font.deriveFont(font.getSize() * 1.7f);
io.setFont(font);
io.setHorizontalAlignment(SwingConstants.TRAILING);
io.setFocusable(false);
text.add(io);

JPanel buttons = new JPanel(new GridLayout(4, 4, 2, 2));
gui.add(buttons, BorderLayout.CENTER);
addButton(buttons,"7");
addButton(buttons,"8");
addButton(buttons,"9");
addButton(buttons,"/");

addButton(buttons,"4");
addButton(buttons,"5");
addButton(buttons,"6");
addButton(buttons,"*");

addButton(buttons,"1");
addButton(buttons,"2");
addButton(buttons,"3");
addButton(buttons,"-");

addButton(buttons,"0");
addButton(buttons,".");
addButton(buttons,"C");
addButton(buttons,"+");

JButton equals = new JButton("=");
equals.addKeyListener(this);
controls.add(equals);
equals.addActionListener(this);
gui.add(equals, BorderLayout.EAST);

gui.setBorder(new EmptyBorder(5, 5, 5, 5));

final JFrame f = new JFrame("Calculet");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(gui);
f.pack();
f.setMinimumSize(f.getSize());
f.setLocationByPlatform(true);
f.setVisible(true);

final ComponentListener cl = new ComponentAdapter() {

@Override
public void componentResized(ComponentEvent e) {
int ii = getMaxFontSizeForControls();
for (JButton b : controls) {
if (!b.getText().equals("=")) {
b.setFont(b.getFont().deriveFont((float) ii));
}
}
}
};
ActionListener al = new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
f.addComponentListener(cl);
}
};
Timer t = new Timer(500, al);
t.setRepeats(false);
t.start();
}

public void addButton(Container c, String text) {
JButton b = new JButton(text);
b.addActionListener(this);
b.addKeyListener(this);
controls.add(b);
c.add(b);
}

public void calculateResult() {
try {
Object result = engine.eval(io.getText());
if (result == null) {
io.setText("Output was 'null'");
} else {
io.setText(result.toString());
}
} catch (ScriptException se) {
io.setText(se.getMessage());
}
}

public void actionPerformed(ActionEvent ae) {
String command = ae.getActionCommand();
if (command.equals("C")) {
io.setText("");
} else if (command.equals("=")) {
calculateResult();
} else {
io.setText(io.getText() + command);
}
}

private JButton getButton(String text) {
for (JButton button : controls) {
String s = button.getText();
if (text.endsWith(s)
|| (s.equals("=")
&& (text.equals("Equals") || text.equals("Enter")))) {

return button;
}
}
return null;
}

/*
* START - Because I hate mice.
*/
public void keyPressed(KeyEvent ke) {
}

public void keyReleased(KeyEvent ke) {
String s = ke.getKeyText(ke.getKeyCode());
JButton b = getButton(s);
if (b != null) {
b.requestFocusInWindow();
b.doClick();
}
}

public void keyTyped(KeyEvent ke) {
}

public static void main(String[] args) {
Runnable r = new Runnable() {

@Override
public void run() {
new SwingCalculator();
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency
SwingUtilities.invokeLater(r);
}
}