我正在制作一个按钮，当你点击它时它会改变文字。但是当我单击按钮并更改文本时，按钮不会根据文本更改大小。相反，它变小了，并试图做到这一点＆＃34; ...＆＃34;没有足够空间的东西。这是我的代码：
Text.java
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test {
public static void main(String[] args){
JFrame frame = new JFrame();
JPanel panel = new JPanel();
frame.add(panel);
final CButton button = new CButton("");
panel.add(button);
button.addMouseListener(new MouseListener(){
@Override
public void mouseClicked(MouseEvent arg0) {
button.setText(button.getText()+"f");
}
@Override
public void mouseEntered(MouseEvent arg0) {
}
@Override
public void mouseExited(MouseEvent arg0) {
}
@Override
public void mousePressed(MouseEvent arg0) {
}
@Override
public void mouseReleased(MouseEvent arg0) {
}
});
frame.setSize(500,500);
frame.setVisible(true);
}
}
CButton.java
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.geom.Area;
import java.awt.geom.Rectangle2D;
import java.awt.geom.RoundRectangle2D;
import javax.swing.JButton;
import javax.swing.JOptionPane;
public class CButton extends JButton implements ComponentListener, KeyListener {
protected static final int BORDER_WIDTH = 5;
private static final Font font = new Font("Arial", Font.PLAIN, 30);
private static final Insets INSETS_MARGIN = new Insets(2, 5, 2, 5);
private static final long serialVersionUID = 1L;
protected Area m_areaDraw = null;
private Area m_areaFill = null;
private double m_dHeightDraw = 0d;
private double m_dHeightFill = 0d;
private double m_dWidthDraw = 0d;
private double m_dWidthFill = 0d;
private int m_nMinHeight = 0;
private int m_nMinWidth = 0;
private int m_nStringHeightMax = 0;
private int m_nStringWidthMax = 0;
private RoundRectangle2D m_rrect2dDraw = null;
private RoundRectangle2D m_rrect2dFill = null;
private Shape m_shape = null;
public CButton(String strLabel) {
super(strLabel);
setContentAreaFilled(false);
setMargin(CButton.INSETS_MARGIN);
setFocusPainted(false);
addComponentListener(this);
addKeyListener(this);
// Determine the buttons initial size
setFont(CButton.font);
Frame frame = JOptionPane.getRootFrame();
FontMetrics fm = frame.getFontMetrics(getFont());
m_nStringWidthMax = fm.stringWidth(getText());
m_nStringWidthMax = Math.max(m_nStringWidthMax,
fm.stringWidth(getText()));
// WARNING: use getMargin. it refers to dist btwn text and border.
// Also use getInsets. it refers to the width of the border
int nWidth = Math.max(m_nMinWidth, m_nStringWidthMax + getMargin().left
+ this.getInsets().left + getMargin().right
+ this.getInsets().right);
m_nStringHeightMax = fm.getHeight();
// WARNING: use getMargin. it refers to dist btwn text and border.
// Also use getInsets. it refers to the width of the border
int nHeight = Math.max(m_nMinHeight, m_nStringHeightMax
+ getMargin().left + this.getInsets().left + getMargin().right
+ this.getInsets().right);
setPreferredSize(new Dimension(
nWidth + ((2 * getFont().getSize()) / 5), nHeight
+ ((2 * getFont().getSize()) / 5)));
// Set the initial draw and fill dimensions
setShape();
}
@Override
public void componentHidden(ComponentEvent e) {
}
@Override
public void componentMoved(ComponentEvent e) {
}
// Needed if we want this button to resize
@Override
public void componentResized(ComponentEvent e) {
m_shape = new Rectangle2D.Float(0, 0, getBounds().width,
getBounds().height);
m_dWidthFill = (double) getBounds().width - 1;
m_dHeightFill = (double) getBounds().height - 1;
m_dWidthDraw = ((double) getBounds().width - 1)
- (CButton.BORDER_WIDTH - 1);
m_dHeightDraw = ((double) getBounds().height - 1)
- (CButton.BORDER_WIDTH - 1);
setShape();
repaint();
}
@Override
public void componentShown(ComponentEvent e) {
}
@Override
public boolean contains(int nX, int nY) {
if ((null == m_shape) || m_shape.getBounds().equals(getBounds())) {
m_shape = new Rectangle2D.Float(0, 0, this.getBounds().width,
this.getBounds().height);
}
return m_shape.contains(nX, nY);
}
// This is so the button is triggered when it has focus
// and we press the Enter key.
@Override
public void keyPressed(KeyEvent e) {
if ((e.getSource() == this) && (e.getKeyCode() == KeyEvent.VK_ENTER)) {
doClick();
}
};
@Override
public void keyReleased(KeyEvent e) {
};
@Override
public void keyTyped(KeyEvent e) {
};
@Override
public void paintBorder(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHints(hints);
g2.setColor(Color.black);
Stroke strokeOld = g2.getStroke();
g2.setStroke(new BasicStroke(CButton.BORDER_WIDTH,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
g2.draw(m_areaDraw);
if (getModel().isRollover()) {
g2.setColor(Color.GRAY);
g2.draw(m_areaDraw);
}
g2.setStroke(strokeOld);
};
@Override
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setRenderingHints(hints);
if (getModel().isArmed()) {
g2.setColor(Color.CYAN.darker());
} else {
g2.setColor(Color.CYAN);
}
g2.fill(m_areaFill);
super.paintComponent(g2);
}
private void setShape() {
// Area
double dArcLengthFill = Math.min(m_dWidthFill, m_dHeightFill);
m_rrect2dFill = new RoundRectangle2D.Double(0d, 0d, m_dWidthFill,
m_dHeightFill, dArcLengthFill, dArcLengthFill);
// WARNING: arclength and archeight are divided by 2
// when they get into the roundedrectangle shape
m_areaFill = new Area(m_rrect2dFill);
// Border
double dArcLengthDraw = Math.min(m_dWidthDraw, m_dHeightDraw);
m_rrect2dDraw = new RoundRectangle2D.Double(
(CButton.BORDER_WIDTH - 1) / 2, (CButton.BORDER_WIDTH - 1) / 2,
m_dWidthDraw, m_dHeightDraw, dArcLengthDraw, dArcLengthDraw);
m_areaDraw = new Area(m_rrect2dDraw);
}
@Override
public void setText(String strText) {
super.setText(strText);
int nWidth = Math.max(m_nMinWidth, m_nStringWidthMax + getInsets().left
+ getInsets().right);
int nHeight = Math.max(0, getPreferredSize().height);
setPreferredSize(new Dimension(nWidth, nHeight));
m_dWidthFill = getBounds().width - 1;
m_dHeightFill = getBounds().height - 1;
if ((m_dWidthFill <= 0) || (m_dHeightFill <= 0)) {
m_dWidthFill = (double) getPreferredSize().width - 1;
m_dHeightFill = (double) getPreferredSize().height - 1;
}
m_dWidthDraw = m_dWidthFill - (CButton.BORDER_WIDTH - 1);
m_dHeightDraw = m_dHeightFill - (CButton.BORDER_WIDTH - 1);
setShape();
}
}
答案 0 :(得分：1)
你打电话
setPreferredSize(new Dimension(
nWidth + ((2 * getFont().getSize()) / 5), nHeight
+ ((2 * getFont().getSize()) / 5)));
在构造函数中，但永远不会更改它。这意味着每次布局管理器询问组件它想要的大小时，它总是得到相同的值。
首选解决方案是覆盖getPreferredSize并计算其大小，如果它不复杂或耗时
接下来的问题是你为什么要付出这么多额外的努力。基本上，您应该只允许父JButton提供其首选尺寸并在其周围添加您的要求，或者只使用margins属性甚至是Border
你KeyListener似乎也没用，因为这是按钮的默认行为，无论如何，关键绑定将是首选解决方案
答案 1 :(得分：0)
我的第一个想法是它与你的大量CButton实施有关。至少，复制/粘贴代码创建了一个有效的应用程序。这是我书中的一大优点。
当我简单地用nWidth方法替换奇怪的setText()计算时使用：
int nWidth = 100;
点击后尺寸增加并显示“f”，我认为这是你想要的。
所以，我不能真正说出如何计算宽度，但至少你知道在哪里寻找和改变哪条线。