Konular
Videolar
Sunular
Testler

Dosya Gezinti Peceresi Açmak

NetBeans IDE'si ile bir dosya açma penceresi açarak dosya sisteminde gezinti yapan ve sonuçta seçilen dosyayı ekrana yazıp, kaç karakterden oluştuğunu veren bir uygulama.

 


// File   : filechooser/CountWords.java
// Purpose: Counts words in file.
//          Illustrates menus, JFileChooser, Scanner..
// Author : Fred Swartz
// Date   : 2005-02-23, 2005-12-02
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;

//////////////////////////////////////////////////////// CountWords
public class CountWords extends JFrame {

    //... Instance variables
    JTextField m_fileNameTF = new JTextField(15);
    JTextField m_wordCountTF = new JTextField(4);
    JFileChooser m_fileChooser = new JFileChooser();

    //================================================== constructor
    CountWords() {
        m_fileNameTF.setEditable(false);
        m_wordCountTF.setEditable(false);
        JButton openButton = new JButton("Open");

        //... Add listeners
        openButton.addActionListener(new OpenAction());

        //... Create contant pane, layout components
        JPanel content = new JPanel();
        content.setLayout(new FlowLayout());
        content.add(openButton);
        content.add(m_fileNameTF);
        content.add(new JLabel("Word Count"));
        content.add(m_wordCountTF);

        //... Set window characteristics
        this.setTitle("Count Words");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setContentPane(content);
        this.pack();
    }

    //============================================= countWordsInFile
    private int countWordsInFile(File f) {

        int numberOfWords = 0;  // For counting words.

        try {
            Scanner wordScanner = new Scanner(f);
            wordScanner.useDelimiter("[^A-Za-z]+");

            while (wordScanner.hasNext()) {
                String word = wordScanner.next();
                numberOfWords++;
            }
            wordScanner.close();     // Close Scanner's file.

        } catch (FileNotFoundException fnfex) {
            JOptionPane.showMessageDialog(CountWords.this, "You gave me an unreadable file");
        }
        return numberOfWords;
    }


    ///////////////////////////////////////////////////// OpenAction
    class OpenAction implements ActionListener {

        public void actionPerformed(ActionEvent ae) {
            //... Open a file dialog.
            int retval = m_fileChooser.showOpenDialog(CountWords.this);
            if (retval == JFileChooser.APPROVE_OPTION) {
                //... The user selected a file, process it.
                File file = m_fileChooser.getSelectedFile();

                //... Update user interface.
                m_fileNameTF.setText(file.getName());
                m_wordCountTF.setText("" + countWordsInFile(file));
            }
        }
    }

    //========================================================= main
    public static void main(String[] args) {
        JFrame window = new CountWords();
        window.setVisible(true);
    }
}
 

 

Dosya Gezinti Peceresi AçmakDosya Gezinti Peceresi AçmakDosya Gezinti Peceresi Açmak

To display a file chooser

Use one of three methods to display the dialog after it has been created.

 
   r = fc.showOpenDialog(owner); // button labeled "Open"
   r = fc.showSaveDialog(owner); // button labeled "Save"
   r = fc.showDialog(owner, title);

The owner parameter is the component (eg, JFrame, JPanel, ...) over which the dialog should be centered. You can use null for the owner, which will put the dialog in the center of the screen. To get the enclosing class's instance, as in this example, write the enclosing class name followed by ".this". The title parameter is a string that is used as the dialog's title and accept button text.

Checking the return value

The user may either select a file or directory, or click CANCEL or close the file chooser window. If the user selected a file or directory, the value returned will be JFileChooser.APPROVE_OPTION. Always check this value. For example,

int retval = fc.showOpenDialog(null);
if (retval == JFileChooser.APPROVE_OPTION) {
    . . . // The user did select a file.;

Getting the selected file or directory

After checking for JFileChooser.APPROVE_OPTION, the File value of the selection is returned from a call on getSelectedFile.

int retval = fc.showOpenDialog(null);
if (retval == JFileChooser.APPROVE_OPTION) {
    File myFile = fc.getSelectedFile();
    // DO YOUR PROCESSING HERE. OPEN FILE OR ...
}

Why a file chooser is often an instance variable

Altho a new file chooser can be created inside a listener, there are advantages to creating it once outside and reusing it.

  • A file chooser remembers the directory that was last used so any reuse opens in the same directory.
  • It is also more efficient since it is created only once and customizations only have to be done once. This increases the response speed.

Files, directories, or both

By default a file chooser allows the user to select only files. To allow selection of either files or directories, or only directories, use one of the following calls.

   fc.setFileSelectionMode(JFileChooser.FILES_ONLY);   // default
   fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
   fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);

Filtering files

You can specify the kinds of files that should be shown (eg, with a specific extension, ...), but supplying a JFileFilter.

 
   myChooser.setFileFilter(FileFilter filter);

See FileFilter. [NEEDS MORE WORK]

Specify a start directory in the constructor

The file chooser will start the file dialog at some default directory, for example, "C:My Documents". To start the dialog at a different directory (called the current directory), specify the directory path as a String or File value in the JFileChooser constructor.

JFileChooser m_fileChooser = new JFileChooser("C:home");

The current directory is ".".

Portability warning: If you put system specific file paths in your code, the program will not be portable to other systems. Note that the above call is therefore not portable.

Kaynak www.roseindia.net/java/java-tips/GUI/containers/20dialogs/30filechooser.shtml

19,663 Okunma Henüz yorum yapılmamış 07/11/2008 10:41:35

Yorumunuzu Ekleyin

Java Applet Nedir?

Applet örnekleri,applet ve japplet farkı

48,090 Okunma 4 Yorum 05/03/2010 09:49:53

Java Applet Nedir?

Java applet nedir?apllet Örnekleri,applet ve japplet farkı

30,626 Okunma 1 Yorum 11/03/2010 08:59:42

Java Applet Layout Kullanımları

setLayout(null); setLayout(new FlowLayout()); setLayout(new BorderLayout()); new CardLayout(); Yerleşim Yöneticileri

29,117 Okunma 1 Yorum 26/01/2010 00:09:26 12/04/2017 00:12:53

Connecting to a MySQL Database

This document demonstrates how to set up a connection to a MySQL database from NetBeans IDE 6.1. Once connected, you can begin working with MySQL in the IDE's Database Explorer by creating new databases and tables, populating tables with data, and running SQL queries on database structures and content. This tutorial is designed for beginners with a basic understanding of database management, who want to apply their knowledge to working with MySQL in NetBeans IDE.

26,796 Okunma Henüz yorum yapılmamış 16/10/2008 18:48:41

Applet Nedir?

Appletlerin temel özellikleri ve kısıtlamalarının aşılması

25,384 Okunma Henüz yorum yapılmamış 03/01/2009 05:42:13

Java Aplleti imzalamak (Signed applet)

Security manager adlı sistemi sayesinde koda bazı sınırlamalar koyarak kullanıcıya zarar vermesi önlenir. Appletlerdeki bu sınırlamayı aşmanın tek yolu signed applet yaratmaktır

24,921 Okunma Henüz yorum yapılmamış 03/07/2010 17:36:51

Kullanıcının Bilgisayarında İşlem Yapmaya Yetkili Güvenilir (Signed) Applet Yazmak

Applet kodlarınız kendi makinenizde sorunsuzca çalışıyor ancak webe attığınızda çalışmıyorsa sebebi appletlerin güvenlik sınırlamalarıdır. Bunu aşmak için appleti imzalamalısınız ve kullanıcılarda appletin bilgisayarlarında yapabileceklerini kabul ettiklerinde ancak applet çalışacaktır. Buna Yerel Dosya Sistemine Erişmeye Yetkili Güvenilir Applet yazmakta denebilir.

24,424 Okunma 1 Yorum 04/07/2010 16:19:54

Java İlk Kodlar (jcreator)

Java classpath tanımlamaları, consolda ilk program yazılması, derlenmesi, çalıştırılması aynı uygulamanın netbeansta yapılışı ve class, java ve jar dosyalarının gösterilmesi

23,458 Okunma Henüz yorum yapılmamış 27/10/2008 14:22:54

Java Applet JFileChooser

Java swing arayüzlerinden - dosya sistemine erişimi sağlayan JFileChooser sınıfının detayları

22,203 Okunma Henüz yorum yapılmamış 19/07/2010 23:39:20

Yükleniyor...