请问getPropertyName()方法究竟有多少种取值？或者告知一下这些值是在哪里定义的？

Question

以下是一段在进度条中显示进度百分比的代码public void propertyChange(PropertyChangeEvent evt) {if ("progress" == evt.getPropertyName()) {int value = (Integer) evt.getNewValue();progressBar.setIndeterminate(false);progressBar.setValue(value);}}我想问的是，if ("progress" == evt.getPropertyName()) 这一句中，"progress"这个字符串是怎么来的？我还看到过"state" == evt.getPropertyName()、"done" == evt.getPropertyName()这样的语句，"state"、"done"这样的字符串又是怎么来的？

Answer 1

package com;

import javax.swing.SwingUtilities;

import java.awt.BorderLayout;

import javax.swing.JPanel;

import javax.swing.JFrame;

import javax.swing.JProgressBar;

import java.awt.Rectangle;

public class T extends JFrame {

private static final long serialVersionUID = 1L;

private JPanel jContentPane = null;

private JProgressBar jProgressBar = null;

private JProgressBar getJProgressBar() {

if (jProgressBar == null) {

jProgressBar = new JProgressBar();

jProgressBar.setBounds(new Rectangle(47, 94, 201, 19));

jProgressBar.addPropertyChangeListener("name",

new java.beans.PropertyChangeListener() {

public void propertyChange(java.beans.PropertyChangeEvent e) {

System.out.println("asd:"+e.getPropertyName()); 

}

});

jProgressBar.addMouseListener(new java.awt.event.MouseAdapter() {

public void mouseClicked(java.awt.event.MouseEvent e) {

jProgressBar.setName("asdf");

}

});

}

return jProgressBar;

}

public static void main(String[] args) {

SwingUtilities.invokeLater(new Runnable() {

public void run() {

T thisClass = new T();

thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

thisClass.setVisible(true);

}

});

}

public T() {

super();

initialize();

}

private void initialize() {

this.setSize(300, 200);

this.setContentPane(getJContentPane());

this.setTitle("JFrame");

}

private JPanel getJContentPane() {

if (jContentPane == null) {

jContentPane = new JPanel();

jContentPane.setLayout(null);

jContentPane.add(getJProgressBar(), null);

}

return jContentPane;

}

}

用户鼠标点击进度条，看一下后台的输出就知道了。其实可以设置的值包含在附件图中，即一种事件监听一种属性的变化

Answer 2

package com;
import javax.swing.SwingUtilities;
import java.awt.BorderLayout;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JProgressBar;
import java.awt.Rectangle;
public class T extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel jContentPane = null;
private JProgressBar jProgressBar = null;
private JProgressBar getJProgressBar() {
if (jProgressBar == null) {
jProgressBar = new JProgressBar();
jProgressBar.setBounds(new Rectangle(47, 94, 201, 19));
jProgressBar.addPropertyChangeListener("name",
new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent e) {
System.out.println("asd:"+e.getPropertyName());
}
});
jProgressBar.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent e) {
jProgressBar.setName("asdf");
}
});
}
return jProgressBar;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
T thisClass = new T();
thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
thisClass.setVisible(true);
}
});
}
public T() {
super();
initialize();
}
private void initialize() {
this.setSize(300, 200);
this.setContentPane(getJContentPane());
this.setTitle("JFrame");
}
private JPanel getJContentPane() {
if (jContentPane == null) {
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.add(getJProgressBar(), null);
}
return jContentPane;
}
}
用户鼠标点击进度条，看一下后台的输出就知道了。其实可以设置的值包含在附件图中，即一种事件监听一种属性的变化