第二个Issue的进度很怪，谈不上快还是慢，事实是从网上找了好久找到了一些相关的例子，以此，可以初步作出一个符合要求的"Add image preview window to JFileChooser. add an Image Filter, only image file can be choosed. "
例子来自网上，图片预览控件借助JFileChooser.setAccessory(JComponent newAccessory)添加，JFileChooser类封装得死死的，什么也挖不出来，先后找到了FileFilter、FileSystemView、FileView，借此实现了针对任意扩展名的Filter，Filter解决得差不多，反过来image preview又需要完善了，希望呈现一种windows环境中文件浏览器可以提供的所谓Thumbnails（缩略图），回过头去狂查JFileChooser，不知该从哪里入手，先后在FileView（用图片本身代替文件固有图标）和FileSystemView（借用系统本身标准文件系统的图标）中找到一些有用的东西，二者互助实现了稍微好一点的缩略图策略，当然我个人还不是很满意，为什么就不能想windows里面那样给我痛快地显示出来呢？问题估计还是sun的JFileChooser太旧了，也不更新下，你说就算不更新，也给我们一些开放度大点的东西吧，啧啧，非逼得我挑剔。期间，试用了UIManager的Look and Feel，找到windows下面的，看来下还凑合，只是左边的快捷图标怎么没有scrollpane呢？郁闷死我。
任务仍在进一步完善中，我也逐渐培养自己写这种业余水平的总结心得的习惯，但愿以后既有很规范的文档总结，有能有我自己独特的心路历程吧。以下附代码，比较长，中间尽量也放些讲解，技术blog可能这点好很多吧，其他的都还限制长度。
ps:中间一度查阅提供给我的英文网页，看的吐血了n次。以后还会碰到很多，初步需要jdk中的demo和api 源代码，其次借助tutorial、doc和javaworld等其他一些文档资料，进一步了解java，还下了一个java实用程序设计100例原代码和素材，不知有用没。
1. FileChooserDemo，主演示类，在第三个按钮下是JFileChooser，里面添加预览和Filter
import
java.io.
*
;
import
java.awt.
*
;
import
java.awt.event.
*
;
import
javax.swing.
*
;
import
javax.swing.event.
*
;
public
class
FileChooserDemo
extends
JFrame
...
{
private JButton btn1, btn2, btn3, btn4;
private JTextArea area;
private ObjectOutputStream output;
private JScrollPane scroll;
private JPanel panel;
public FileChooserDemo() ...{
super("FileChooser Demo");
btn1 = new JButton("Open Directory");
btn1.addActionListener(new ActionListener() ...{
public void actionPerformed(ActionEvent e) ...{
JFileChooser choose = new JFileChooser();
choose.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
int result = choose.showOpenDialog(null);
if (result == JFileChooser.APPROVE_OPTION)// if approve (yes,
// ok) is chosen
...{
File file = choose.getSelectedFile();
if (!file.exists())
area.append("File does not exist~!");
else if (file.isDirectory()) ...{
area.append("Directory " + file.getName()
+ " containt following files: ");
for (int i = 0; i < file.list().length; i++)
area.append(file.list()[i] + " ");
} else if (file.isFile())
area
.append("It is a file, please use the second button to hava another test ");
} else
return;
}
});
btn2 = new JButton("Open a file");
btn2.addActionListener(new ActionListener() ...{
public void actionPerformed(ActionEvent e) ...{
JFileChooser choose = new JFileChooser();
choose.setFileSelectionMode(JFileChooser.FILES_ONLY);
int result = choose.showOpenDialog(null);
if (result == JFileChooser.APPROVE_OPTION)// if approve (yes,
// ok) is chosen
...{
File file = choose.getSelectedFile();
if (!file.exists())
area.append("File does not exist~!");
else ...{
try ...{
output = new ObjectOutputStream(
new FileOutputStream(file));
// .....
// tobeContinued
} catch (IOException ioexception) ...{
area.append(ioexception.toString());
}
}
} else
return;
}
});
btn3 = new JButton("Images File Filter");
btn3.addActionListener(new ActionListener() ...{
public void actionPerformed(ActionEvent e) ...{
JFileChooser choose = new JFileChooser();
// add ImagePreviewPanel Accessory
ImagePreviewPanel preview = new ImagePreviewPanel();
choose.setAccessory(preview);
choose.addPropertyChangeListener(preview);
choose.setFileSelectionMode(JFileChooser.FILES_ONLY);
/**//*
* //add FindAccessory FindAccessory search = new
* FindAccessory(); choose.setAccessory(search);
* choose.addPropertyChangeListener(search);
* choose.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
*/
// add Filters
String htmlExts[] = ...{ "html", "htm" };
String imageExts[] = ...{ "jpg", "jpeg", "png", "gif","bmp" };
// construct it giving it an array of file
// extensions and a description string
GenericFileFilter filter = new GenericFileFilter(htmlExts,
"HTML Files");
choose.addChoosableFileFilter(filter);
filter = new GenericFileFilter(imageExts,
"Images Files(*.jpg;*.jpeg;*.png;*.gif;*.bmp)");
choose.addChoosableFileFilter(filter);
choose.setFileView(new GenericFileView(imageExts,
GenericFileView.IMAGE_FILEVIEW));
/**//*
* addChoosableFileFilter(Filter filter) and
* setFileFilter(Filter filter) are two familiar methods,they
* both add the filter to the JFileChooser, the difference is
* the setFileFilter set itself to the default choose.
*/
int result = choose.showOpenDialog(null);
if (result == JFileChooser.APPROVE_OPTION)// if approve (yes,
// ok) is chosen
...{
File file = choose.getSelectedFile();
if (!file.exists())
area.append("File does not exist~!");
else
area.append("You chose " + file.getName() + " ");
} else
return;
}
&nb
