Open Dialog JFileChooser

[James Hambrick]

Okay again I have this same project and Im trying to get the Open and save dialog boxes to show when the user clicks the appropriate menu item.

I have seen the example on Sun's website, but the menu action listener is another class then the one that implements the gui.

I get the error
JFileChooser cannot be applied to UNTFgui.
on this line of code
int returnVal = fc.showOpenDialog(UNTFgui.this);

class UNTFgui
{
JFileChooser fc;
 

  UNTgui()
  {
   fc = new JFileChooser();
   fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
  }
 
}
 
public class UNTFuserGuiCommand implements ActionListener
{
    public void actionPerformed(ActionEvent ae)
    {
        String s = ae.getActionCommand();
        
        if(s.equals("OPEN"))
        {
            int returnVal = fc.showOpenDialog(UNTFgui.this);
 
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                File file = fc.getSelectedFile();
                //This is where a real application would open the file.
                System.out.println("Opening: " + file.getName() + ".");
            } else {
                System.out.println("Open command cancelled by user.");
            }
          
            
        }
 
}

[Ulf Dittmer]

Have you tried passing in "null" as the parameter to showOpenDialog, like the javadocs suggest?

[Rob Spoor]

You can only use an instance of Component or a subclass, and your UNTFgui class does not meet that requirement.

So either you have to create a component (like a applet, frame or panel), or just use null as Ulf said.

[James Hambrick]

if I use null will the file I open still open up inside the appropriate textArea?

[James Hambrick]

Also how in the world do I add a filter so it will only open up a certain file extension. I have read through the Java Tutorial and it does not help, I have also looked at the API.

[Rob Spoor]

import javax.swing.filechooser.FileFilter; // so not java.io.FileFilter
 
...
 
FileFilter filter = new FileFilter()
{
    public String getDescription()
    {
        return "Text Files (*.txt)";
    }
 
    public boolean accept(File file)
    {
        String name = file.getName();
        return name.endsWith(".txt");
    }
};
fc.setFileFilter(filter);
fc.setAcceptAllFileFilterUsed(false);

You can also perform slightly other checks; use "name.regionMatches(true, name.length - 4, ".txt", 0, 4)" to check while ignoring the case.

There is one draw back: when saving, JFileChooser allows any typed in value. If that value does not include the correct extension, it is not added automatically but you have to do it yourself.

[Ulf Dittmer]

Have you looked at the "public void addChoosableFileFilter (FileFilter filter)" method? It would seem to do what you're asking.

[James Hambrick]

Alright! I got it to work, even on a separate file!. Now I just have to have it actually read and write the file. Yah!