[JAVA100 Example]017, file dialog box

Import Java.io.File;


import javax.swing.*;


import javax.swing.filechooser.*;


/**


* <p>title: File filter Demo </p>


* <p>description:filechooserdemo file filter </p>


* <p>copyright:copyright (c) 2003</p>


* <p>Filename:MyFilter.java</p>


* @version 1.0


*/





public class Myfilter extends FileFilter {


private String files;


public Boolean accept (File f) {


if (f.isdirectory ()) {


return true;


　　　　}





String Extension = getextension (f);


if (extension!= null) {


　　　　　


if (extension.equals ("Java")) {//Define filtering Java file


return true;


} else {


return false;


　　　　　　}





}





return false;


　　}





//Filter Description


public String getdescription () {


return "Java";


　　}


/**


*<br> Method Description: Get the file name extension


*<br> input Parameters:


*<br> return type:


*/


public static String getextension (File f) {


String ext = null;


String s = f.getname ();


int i = S.lastindexof (´.´);





if (i > 0 && i < s.length ()-1) {


ext = s.substring (i+1). toLowerCase ();


　　　　}


return ext;


　　}


}





import java.io.*;


import java.awt.*;


import java.awt.event.*;


import javax.swing.*;


Import javax.swing.filechooser.*;


/**


* <p>title: File Dialog Demo </p>


* <p>description: Demo Open File dialog box and save File dialog box, use file filter. </p>


* <p>copyright:copyright (c) 2003</p>


* <p>Filename:FileChooserDemo.java</p>


* @version 1.0


*/





public class Filechooserdemo extends JPanel


implements ActionListener {


static private final String newline = "\ n";


JButton Openbutton, Savebutton;


JTextArea log;


JFileChooser FC;





public Filechooserdemo () {


Super (New BorderLayout ());





log = new JTextArea (15,40);


Log.setmargin (New Insets (10,10,10,10));


log.seteditable (FALSE);


JScrollPane Logscrollpane = new JScrollPane (log);





//Create a file filter using the current directory


FC = new JFileChooser (".");


//filter conditions are defined in the Myfilter class


Fc.addchoosablefilefilter (New Myfilter ());





Openbutton = new JButton ("Open File",


Createimageicon ("Images/open16.gif"));


Openbutton.addactionlistener (this);





Savebutton = new JButton ("Save File",


Createimageicon ("Images/save16.gif"));


Savebutton.addactionlistener (this);





//Build a panel, add "Open File" and "Save File"


JPanel Buttonpanel = new JPanel ();


Buttonpanel.add (Openbutton);


Buttonpanel.add (Savebutton);





Add (Buttonpanel, Borderlayout.page_start);


Add (Logscrollpane, borderlayout.center);


　　}


/**


*<br> Method Description: Event handling


*<br> input Parameters:


*<br> return type:


*/


public void actionperformed (ActionEvent e) {





//When clicking on the "Open File" button


if (e.getsource () = = Openbutton) {


int returnval = Fc.showopendialog (filechooserdemo.this);





if (returnval = = jfilechooser.approve_option) {


File File = Fc.getselectedfile ();


//Add some processing to the file here


log.append ("Open file:" + file.getname () + newline);


} else {


log.append ("Open file cancelled by user!") "+ newline);


　　　　　　}





//Click on the "Save File" button


} else if (E.getsource () = Savebutton) {


int returnval = Fc.showsavedialog (filechooserdemo.this);


if (returnval = = jfilechooser.approve_option) {


File File = Fc.getselectedfile ();


//Add some processing to the file here


log.append ("Save file:" + file.getname () + newline);


} else {


log.append ("Save file canceled by user!") "+ newline);


　　　　　　}


　　　　}


　　}


/**


*<br> Method Description: Get Image Object


*<br> input parameter: String path picture Path


*<br> return type: ImageIcon Picture Object


*/


protected static ImageIcon Createimageicon (String path) {


Java.net.URL imgurl = FileChooserDemo.class.getResource (path);


if (imgurl!= null) {


return new ImageIcon (Imgurl);


} else {


System.err.println ("couldn´t Find File:" + path);


return null;


　　　　}


　　}





public static void Main (string[] args) {


Jframe.setdefaultlookandfeeldecorated (TRUE);


jdialog.setdefaultlookandfeeldecorated (TRUE);





//Create form


JFrame frame = new JFrame ("Filechooserdemo");


frame.setdefaultcloseoperation (jframe.exit_on_close);





//Create a panel


jcomponent Newcontentpane = new Filechooserdemo ();


Newcontentpane.setopaque (TRUE);


Frame.setcontentpane (Newcontentpane);





//Display form


Frame.pack ();


frame.setvisible (TRUE);


　　}


}