CODEWITHSUNDEEP
javaswingawtjfilechooserfile-extension
zealouscoder
zealouscoder

Reputation: 94

Program to check whether extension of a file is .txt

I wrote a java code having an awt text field and a button, where if I click on the button, I can browse a file using JFileChooser. It needs to check whether the file has ".txt" extension or not.I wrote the code below, but it is not getting verified.

Where am I going wrong? Please help to determine where I am wrong.

         try{
            final JFileChooser chooser = new JFileChooser();
            chooser.showOpenDialog(null);
            chooser.addChoosableFileFilter(new FileFilter() {
            public String getDescription() {
                return "*.txt";
            }
            public boolean accept(File filename)
            {

                if(filename.getName().endsWith(".txt")){
                    return true;
                }
                else{
                System.out.println("Browsed dest file extension must be .txt");
                return false;
                }}
            });
        catch(Exception ex)
        {
            JOptionPane.showMessageDialog(f,"Exception occurred");
        }

Upvotes: 1

Views: 13201

Answers (2)

Michał Kupisiński
Michał Kupisiński

Reputation: 3863

Your problem is that:

chooser.showOpenDialog(null);

stop execution of code until user select a file. Add this line after adding FileFilter and eveyrthing should work ok.

Little explanation:

Method showOpenDialog(Component c) blockexecution of current thread until user action and next line of your code will be executed after the user choose a file. If you invoke after adding a FileFilter once again showOpenDialog it will work as you expect.

Upvotes: 6

Michael
Michael

Reputation: 1237

I would suggest using the @Override annotation for the accept method - see this link @Override explained in Oracle Documentation.

Plus, it would be best to use filename.getName().toLowerCase().endsWith(".txt") instead filename.getName().endsWith(".txt") to ensure that files with the extension .TXT will pass the filter as well.

Upvotes: 4

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