我正在阅读一本名为 Swing:A Beginner's guide 的好书。 书中有这段代码创建了一个按钮和一个标签,用于提醒按钮的状态变化事件:
//Demonstrate a change listener and the button model
package swingexample2_6;
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
public class ChangeDemo {
JButton jbtn;
JLabel jlab;
public ChangeDemo() {
//Create a new JFrame container
JFrame jfrm = new JFrame("Button Change Events");
//Specify FlowLayout for the layout manager
jfrm.getContentPane().setLayout(new FlowLayout());
//Give the frame an initial size
jfrm.setSize(250, 160);
//Terminate the program when the user closes the application
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create an empty label
jlab = new JLabel();
//Make a button
jbtn = new JButton("Press for Change Event Test");
//--Add change listener
jbtn.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent ce) {
ButtonModel mod = jbtn.getModel();
String what = "";
if (mod.isEnabled()) {
what += "Enabled<br>";
}
if (mod.isRollover()) {
what += "Rollover<br>";
}
if (mod.isArmed()) {
what += "Armed<br>";
}
if (mod.isPressed()) {
what += "Pressed<br>";
}
//Notice that this label's text is HTML
jlab.setText("<html>Current stats:<br>" + what);
}
});
//Add the components to the content pane
jfrm.getContentPane().add(jbtn);
jfrm.getContentPane().add(jlab);
//Display the frame
jfrm.setVisible(true);
}
public static void main(String[] args) {
//Create the frame on the event dispatching thread
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new ChangeDemo();
}
});
}
}
除了翻转事件外,一切正常。 底层操作系统是 Mac OS Lion。 我应该把这个 Swing 问题归咎于 Lion 还是我做错了什么? 谢谢。
最佳答案
Java 版本的 Leopard 上测试的代码 1.6.0_26
如下所示。尾随 </html>
标签修复了翻滚时的突出显示故障。
附录:使用下面更新的示例,添加 setRolloverEnabled(true)
允许模型按预期工作。有趣的是,Mac UI 代表,com.apple.laf.AquaButtonUI
, 当 isRollover()
时什么都不做是true
.如果它对您的应用程序很重要,您可以在以下谓词为 true
时采取所需的操作。 :
System.getProperty("os.name").startsWith("Mac OS X")
作为引用,这个example演示 setRolloverIcon()
.
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
public class ChangeDemo {
private JButton jbtn;
private JLabel jlab;
public ChangeDemo() {
JFrame jfrm = new JFrame("Button Change Events");
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jfrm.setLayout(new GridLayout(0, 1));
jlab = new JLabel("", JLabel.CENTER);
jbtn = new JButton("Press for Change Event Test");
jbtn.setRolloverEnabled(true);
jbtn.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent ce) {
ButtonModel mod = jbtn.getModel();
String what = "";
if (mod.isEnabled()) {
what += "Enabled<br>";
}
if (mod.isRollover()) {
what += "Rollover<br>";
}
if (mod.isArmed()) {
what += "Armed<br>";
}
if (mod.isPressed()) {
what += "Pressed<br>";
}
//Notice that this label's text is HTML
jlab.setText("<html>Current stats:<br>" + what + "</html>");
}
});
JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createEmptyBorder(50, 10, 0, 10));
panel.add(jbtn);
jfrm.add(panel);
jfrm.add(jlab);
jfrm.pack();
jfrm.setLocationRelativeTo(null);
jfrm.setVisible(true);
}
public static void main(String[] args) {
//Create the frame on the event dispatching thread
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ChangeDemo changeDemo = new ChangeDemo();
}
});
}
}
关于Java isRollover() 方法在我的 swing 应用程序中不产生事件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10036787/