NSSavePanel Changing File Name Extensions With AccessoryView

Question

I have NSSavePanel with accessoryView to let the user select a graphic format so that they can save an image (NSImage) as a file. So far, I have the following. (I'm skipping some lines to make it short.)

- (void)exportFile {    
    NSString *filename;
    if (formatIndex1 == 0) { // Default selection by user in Preferences
        filename = @"Untitled.bmp";
    }
    else if (formatIndex1 == 1) {
        filename = @"Untitled.gif";
    }
    ...

    [panel setAllowedFileTypes:[[NSArray alloc] initWithObjects:@"bmp",@"gif",@"jpg",@"jp2",@"png",nil]];
    [panel setAllowsOtherFileTypes:NO];
    [panel setExtensionHidden:NO];
    [panel setCanCreateDirectories:YES];
    [panel setNameFieldStringValue:filename];
    [panel setAccessoryView:accessoryView1];
    [formatMenu1 setAction:@selector(dropMenuChange:)]; // formatMenu1 is NSPopUpButton
    [formatMenu1 setTarget:self];

    [panel beginSheetModalForWindow:window completionHandler:^(NSInteger result) {
        if (result == NSFileHandlingPanelOKButton) {
            // getting panel url
        }
    }];
}

-(void)dropMenuChange:(NSPopUpButton *)sender { 
    NSSavePanel *savePanel = (NSSavePanel *)[sender window];
    [savePanel setNameFieldStringValue:@"..."];
}

I'm not 100% sure that I'm doing it right. What I want to achieve is that I want to append the right extension to the current file name whenever the user selects a file format on accessoryView's NSPopUpButton. Is there a magical way of doing that? Or do I have to set the current file name with the right extension to setNameFieldStringValue programmatically for myself?

Thank you for your help.

Answer 1

What I want to achieve is that I want to append the right extension to the current file name whenever the user selects a file format on accessoryView's NSPopUpButton. Is there a magical way of doing that?

Yes, there is. You need not do it yourself with setNameFieldStringValue: , let the savePanel do it. Let us assume fileName is a full path like /Users/hg/Pictures/2013/08/Airplanes/pic123.png and it exists an accessoryView for the savePanel with a matrix of radio buttons. Each button has a title like @"jpg" or @"png" or... The action of the matrix is -selectFileType:

- (IBAction) selectFileType:(id)sender
{
    [savePanel setAllowedFileTypes:@[ [[sender selectedCell] title] ] ];
    // this will set the right extension
}

For using the savePanel I tried the following code:

- (void) saveImage:(NSImage *) theImg
{
  savePanel = [NSSavePanel savePanel];
  NSString *imageName = [fileName lastPathComponent];
  NSString *suffix = [imageName pathExtension];
  NSString *baseName = [imageName stringByDeletingPathExtension];

  // prepare the savePanel
  [savePanel setAccessoryView:accessoryView];
  [savePanel setAllowedFileTypes:@[ suffix ] ];
  [savePanel setDirectoryURL:[NSURL fileURLWithPath:fileName]];  // convert to URL
  [savePanel setNameFieldStringValue:baseName ];  // without extension !
  // savePanel does append the suffix

  // and now start the savePanel and choose the wanted fileType
  int rtn = [savePanel runModal];   // preferred method since 10.6
  if( rtn==NSFileHandlingPanelCancelButton) return;    // do nothing

  // finally create and save the file
  if( [[[savePanel allowedFileTypes] objectAtIndex:0] isEqualToString:@"jpg" ){
      // save as jpg-file
  }
  // check for other fileTypes
  . . . 
}