[英]How can I tell when another class has been updated?
I am writing a Java program that displays a combo box that get's it's information from a properties file. 我正在编写一个Java程序,它显示一个组合框,从属性文件中获取它的信息。 There is a settings class that will allow the user to update the names of the fields that are in the combo box.
有一个设置类,允许用户更新组合框中字段的名称。 My problem is when the settings class is called and modified, I cannot figure out how to update the combo box with the new settings.
我的问题是当调用和修改设置类时,我无法弄清楚如何使用新设置更新组合框。 I have a method that will repaint the entire panel and re-load the combo box.
我有一个方法,将重新绘制整个面板并重新加载组合框。 But I do not know how to activate that method when the "apply" button is pressed in the setting class.
但是当我在设置类中按下“apply”按钮时,我不知道如何激活该方法。
Here is a rough and tough example of what I am trying to accomplish. 这是我想要完成的一个粗略而艰难的例子。
Main Class: 主类:
package testing;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.Properties;
import javax.swing.*;
public class testConfigLoad extends JFrame
{
JButton apply = new JButton("Apply");
JButton set = new JButton("Settings");
Properties config = new Properties();
FileInputStream fis = null;
FileOutputStream fos = null;
final String configFile = "config.properties";
OptPanel opt;
public testConfigLoad() throws IOException
{
super("Test Program");
setSize(200, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new FlowLayout());
config();
opt = new OptPanel(config);
buildFrame();
}
public void buildFrame()
{
set.addActionListener(new setListener());
add(opt);
add(apply);
add(set);
setVisible(true);
}
public void config() throws IOException
{
try
{
fis = new FileInputStream(configFile);
config.load(fis);
}
catch (FileNotFoundException e)
{
System.out.println("File not found");
}
finally
{
if (fis != null)
{
fis.close();
}
}
}
private class setListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
settings set = new settings(config);
}
}
public static void main(String[] args) throws IOException
{
new testConfigLoad();
}
}
Panel that needs to be Refreshed: 需要刷新的面板:
package testing;
import java.util.Properties;
import javax.swing.*;
public class OptPanel extends JPanel
{
String[] opts;
JLabel optLabel = new JLabel("Available Options");
Properties config;
public OptPanel(Properties p)
{
config = p;
opts = new String[3];
buildPanel();
}
public void buildPanel()
{
for (int i = 0; i < opts.length; i++)
{
opts[i] = config.getProperty("option." + i + ".name");
}
JComboBox optBox = new JComboBox(opts);
add(optLabel);
add(optBox);
}
public void refPanel()
{
removeAll();
this.buildPanel();
((JPanel) this).revalidate();
repaint();
}
}
And the settings class: 和设置类:
package testing;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
import javax.swing.*;
public class settings
{
Properties config;
final String configFile = "config.properties";
JFrame setFrame = new JFrame("Settings");
JLabel opt1 = new JLabel("Option 1");
JLabel opt2 = new JLabel("Option 2");
JLabel opt3 = new JLabel("Option 3");
JTextField text1 = new JTextField(15);
JTextField text2 = new JTextField(15);
JTextField text3 = new JTextField(15);
JButton apply = new JButton("Apply");
public settings(Properties p)
{
config = p;
setFrame.setSize(275, 200);
setFrame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
setFrame.setLayout(new FlowLayout());
buildSetFrame();
}
public void buildSetFrame()
{
text1.setText(config.getProperty("option.0.name"));
text2.setText(config.getProperty("option.1.name"));
text3.setText(config.getProperty("option.2.name"));
apply.addActionListener(new applyListener());
setFrame.add(opt1);
setFrame.add(text1);
setFrame.add(opt2);
setFrame.add(text2);
setFrame.add(opt3);
setFrame.add(text3);
setFrame.add(apply);
setFrame.setVisible(true);
}
private class applyListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
config.setProperty("option.0.name", text1.getText());
config.setProperty("option.1.name", text2.getText());
config.setProperty("option.2.name", text3.getText());
FileOutputStream fos = null;
try
{
fos = new FileOutputStream(configFile);
config.store(fos, null);
}
catch (IOException f)
{
System.out.println("Error");
}
finally
{
if (fos != null)
{
try
{
fos.close();
}
catch (IOException g)
{
System.out.println("Problem");
}
}
}
setFrame.setVisible(false);
// This is where I need to pass something back to the
// testConfigLoad class to tell it to
// run the refPanel method in the OptPanel class.
}
}
}
The config file is named config.properties and looks like this: 配置文件名为config.properties,如下所示:
option.2.name=two
option.1.name=one
option.0.name=zero
One approach would be to use a callback between the OptPanel
and the settings
class. 一种方法是在
OptPanel
和settings
类之间使用回调。 You could extract out the functionality to add the elements to the properties JComboBox
into its own method: 您可以提取出将属性
JComboBox
到其自己的方法中的功能:
public void updateProperties(Properties p) {
model.removeAllElements();
for (String s: p.stringPropertyNames()) {
model.addElement(p.getProperty(s));
}
}
where model
is a DefaultComboBoxModel
. 其中
model
是DefaultComboBoxModel
。 Then you could simply call 然后你可以简单地打电话
optPanel.updateProperties(config);
after successfully storing the properties. 成功存储属性后。
Some Points: 一些要点:
JFrames
. JFrames
。 One option is to use a single JFrame
with a modal dialog. JFrame
和模态对话框。 See this discussion . settings
would become Settings
settings
将成为Settings
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