我实例化了我的类的一个按钮，如下所示:
linkBtn = new LinkButton(
new URI("http://www.example.com"),
"Click me");
当我点击它时什么也没有发生，所以我想添加一个像这样的 Action 监听器:
linkBtn.addActionListener(SOMETHING);
我尝试过这样的事情:
linkBtn.addActionListener(new LinkButton.OpenUrlAction());
这会产生以下错误:
an enclosing instance that contains LinkButton.OpenUrlAction is required
我还没有找到正确的语法。
这是我扩展 JButton 的类:
import java.awt.Desktop;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.URI;
import javax.swing.JButton;
public class LinkButton extends JButton
implements ActionListener {
/** The target or href of this link. */
private URI target;
final static private String defaultText = "<HTML>Click the <FONT color=\"#000099\"><U>link</U></FONT>"
+ " to go to the website.</HTML>";
public LinkButton(URI target, String text) {
super(text);
this.target = target;
//this.setText(text);
this.setToolTipText(target.toString());
}
public LinkButton(URI target) {
this( target, target.toString() );
}
public void actionPerformed(ActionEvent e) {
open(target);
}
class OpenUrlAction implements ActionListener {
@Override public void actionPerformed(ActionEvent e) {
open(target);
}
}
private static void open(URI uri) {
if (Desktop.isDesktopSupported()) {
try {
Desktop.getDesktop().browse(uri);
} catch (IOException e) { /* TODO: error handling */ }
} else { /* TODO: error handling */ }
}
}
最佳答案
I'm open to suggestions. I don't like my program structure either...
到目前为止提供的答案都非常好。
Hovercraft 建议使用 Action，这将简化代码的结构。
例如...
import java.awt.Desktop;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class LinkButtonExample {
public static void main(String[] args) {
new LinkButtonExample();
}
public LinkButtonExample() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridBagLayout());
frame.add(new JButton(new OpenURLAction(new URL("http://stackoverflow.com/"))));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
}
});
}
public class OpenURLAction extends AbstractAction {
private URL url;
public OpenURLAction(URL url) {
this("<HTML>Click the <FONT color=\\\"#000099\\\"><U>link</U></FONT> to go to the website.</HTML>", url);
}
public OpenURLAction(String text, URL url) {
putValue(NAME, text);
setURL(url);
}
public void setURL(URL url) {
this.url = url;
setEnabled(
url != null
&& Desktop.isDesktopSupported()
&& Desktop.getDesktop().isSupported(Desktop.Action.BROWSE));
putValue(SHORT_DESCRIPTION, url == null ? null : url.toString());
}
public URL getURL() {
return url;
}
@Override
public void actionPerformed(ActionEvent e) {
if (isEnabled()) {
URL url = getURL();
if (url != null && Desktop.isDesktopSupported()
&& Desktop.getDesktop().isSupported(Desktop.Action.BROWSE)) {
try {
Desktop.getDesktop().browse(url.toURI());
} catch ( IOException | URISyntaxException ex) {
ex.printStackTrace();
}
}
}
}
}
}
查看How to use Actions了解更多详情
关于java - 如何将 ActionListener 添加到扩展 JButton 的类的实例？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17246764/