ExampleFileFilter filter=new ExampleFileFilter();
filter.addExtension(".txt");
filter.setDescription("文档文件");
jFileChooser1.setFileFilter(filter);
int num=jFileChooser1.showOpenDialog(this); //调用打开对话框
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ExampleFileFilter的实现是什么？
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我现在在文件类型选择上有（.txt）和所有文件两种，可当我选择.txt时，却看不到所有路径中的.txt文档，不知道是为什么
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你的ExampleFileFilter的代码是什么 ?
这个过滤全靠过滤器
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哦 我是调用的jdk1.4 DEMO中的实例代码
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其实完全可以自己实现
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/*
* Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* -Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* -Redistribution in binary form must reproduct the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT
* BE LIABLE FOR ANY DAMAGES OR LIABILITIES SUFFERED BY LICENSEE AS A RESULT
* OF OR RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE, EVEN
* IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that Software is not designed, licensed or intended for
* use in the design, construction, operation or maintenance of any nuclear
* facility.
*/
/*
* @(#)ExampleFileFilter.java 1.14 03/01/23
*/
package 记事本;
import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.*;
import javax.swing.filechooser.*;
/**
* A convenience implementation of FileFilter that filters out
* all files except for those type extensions that it knows about.
*
* Extensions are of the type ".foo", which is typically found on
* Windows and Unix boxes, but not on Macinthosh. Case is ignored.
*
* Example - create a new filter that filerts out all files
* but gif and jpg image files:
*
* JFileChooser chooser = new JFileChooser();
* ExampleFileFilter filter = new ExampleFileFilter(
* new String{"gif", "jpg"}, "JPEG & GIF Images")
* chooser.addChoosableFileFilter(filter);
* chooser.showOpenDialog(this);
*
* @version 1.14 01/23/03
* @author Jeff Dinkins
*/
public class ExampleFileFilter extends FileFilter {
private static String TYPE_UNKNOWN = "Type Unknown";
private static String HIDDEN_FILE = "Hidden File";
private Hashtable filters = null;
private String description = null;
private String fullDescription = null;
private boolean useExtensionsInDescription = true;
/**
* Creates a file filter. If no filters are added, then all
* files are accepted.
*
* @see #addExtension
*/
public ExampleFileFilter() {
this.filters = new Hashtable();
}
/**
* Creates a file filter that accepts files with the given extension.
* Example: new ExampleFileFilter("jpg");
*
* @see #addExtension
*/
public ExampleFileFilter(String extension) {
this(extension,null);
}
/**
* Creates a file filter that accepts the given file type.
* Example: new ExampleFileFilter("jpg", "JPEG Image Images");
*
* Note that the "." before the extension is not needed. If
* provided, it will be ignored.
*
* @see #addExtension
*/
public ExampleFileFilter(String extension, String description) {
this();
if(extension!=null) addExtension(extension);
if(description!=null) setDescription(description);
}
/**
* Creates a file filter from the given string array.
* Example: new ExampleFileFilter(String {"gif", "jpg"});
*
* Note that the "." before the extension is not needed adn
* will be ignored.
*
* @see #addExtension
*/
public ExampleFileFilter(String[] filters) {
this(filters, null);
}
/**
* Creates a file filter from the given string array and description.
* Example: new ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
*
* Note that the "." before the extension is not needed and will be ignored.
*
* @see #addExtension
*/
public ExampleFileFilter(String[] filters, String description) {
this();
for (int i = 0; i < filters.length; i++) {
// add filters one by one
addExtension(filters[i]);
}
if(description!=null) setDescription(description);
}
/**
* Return true if this file should be shown in the directory pane,
* false if it shouldn't.
*
* Files that begin with "." are ignored.
*
* @see #getExtension
* @see FileFilter#accepts
*/
public boolean accept(File f) {
if(f != null) {
if(f.isDirectory()) {
return true;
}
String extension = getExtension(f);
if(extension != null && filters.get(getExtension(f)) != null) {
return true;
};
}
return false;
}
/**
* Return the extension portion of the file's name .
*
* @see #getExtension
* @see FileFilter#accept
*/
public String getExtension(File f) {
if(f != null) {
String filename = f.getName();
int i = filename.lastIndexOf('.');
if(i>0 && i<filename.length()-1) {
return filename.substring(i+1).toLowerCase();
};
}
return null;
}
/**
* Adds a filetype "dot" extension to filter against.
*
* For example: the following code will create a filter that filters
* out all files except those that end in ".jpg" and ".tif":
*
* ExampleFileFilter filter = new ExampleFileFilter();
* filter.addExtension("jpg");
* filter.addExtension("tif");
*
* Note that the "." before the extension is not needed and will be ignored.
*/
public void addExtension(String extension) {
if(filters == null) {
filters = new Hashtable(5);
}
filters.put(extension.toLowerCase(), this);
fullDescription = null;
}
/**
* Returns the human readable description of this filter. For
* example: "JPEG and GIF Image Files (*.jpg, *.gif)"
*
* @see setDescription
* @see setExtensionListInDescription
* @see isExtensionListInDescription
* @see FileFilter#getDescription
*/
public String getDescription() {
if(fullDescription == null) {
if(description == null || isExtensionListInDescription()) {
fullDescription = description==null ? "(" : description + " (";
// build the description from the extension list
Enumeration extensions = filters.keys();
if(extensions != null) {
fullDescription += "." + (String) extensions.nextElement();
while (extensions.hasMoreElements()) {
fullDescription += ", ." + (String) extensions.nextElement();
}
}
fullDescription += ")";
} else {
fullDescription = description;
}
}
return fullDescription;
}
/**
* Sets the human readable description of this filter. For
* example: filter.setDescription("Gif and JPG Images");
*
* @see setDescription
* @see setExtensionListInDescription
* @see isExtensionListInDescription
*/
public void setDescription(String description) {
this.description = description;
fullDescription = null;
}
/**
* Determines whether the extension list (.jpg, .gif, etc) should
* show up in the human readable description.
*
* Only relevent if a description was provided in the constructor
* or using setDescription();
*
* @see getDescription
* @see setDescription
* @see isExtensionListInDescription
*/
public void setExtensionListInDescription(boolean b) {
useExtensionsInDescription = b;
fullDescription = null;
}
/**
* Returns whether the extension list (.jpg, .gif, etc) should
* show up in the human readable description.
*
* Only relevent if a description was provided in the constructor
* or using setDescription();
*
* @see getDescription
* @see setDescription
* @see setExtensionListInDescription
*/
public boolean isExtensionListInDescription() {
return useExtensionsInDescription;
}
}
这是demo中的那个类，我恐怕现在还不能写这个功能，所以就先拷了一下
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这个类写得不错啊
应该不会出错的
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嗯 ..不错
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那为什么我的程序不能显示.txt文件呢
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