Arrow keys with NSTableView

Question

Is it possible to navigate an NSTableView's editable cell around the NSTableView using arrow keys and enter/tab? For example, I want to make it feel more like a spreadsheet.

The users of this application are expected to edit quite a lot of cells (but not all of them), and I think it would be easier to do so if they didn't have to double-click on each cell.

Answer 1

In Sequel Pro we used a different (and in my eyes simpler) method: We implemented control:textView:doCommandBySelector: in the delegate of the TableView. This method is hard to find -- it can be found in the NSControlTextEditingDelegate Protocol Reference. (Remember that NSTableView is a subclass of NSControl)

Long story short, here's what we came up with (we didn't override left/right arrow keys, as those are used to navigate within the cell. We use Tab to go left/right)

Please note that this is just a snippet from the Sequel Pro source code, and does not work as is

- (BOOL)control:(NSControl *)control textView:(NSTextView *)textView doCommandBySelector:(SEL)command
{
    NSUInteger row, column;

    row = [tableView editedRow];
    column = [tableView editedColumn];

    // Trap down arrow key
    if (  [textView methodForSelector:command] == [textView methodForSelector:@selector(moveDown:)] )
    {
        NSUInteger newRow = row+1;
        if (newRow>=numRows) return TRUE; //check if we're already at the end of the list
        if (column>= numColumns) return TRUE; //the column count could change

        [tableContentView selectRowIndexes:[NSIndexSet indexSetWithIndex:newRow] byExtendingSelection:NO];
        [tableContentView editColumn:column row:newRow withEvent:nil select:YES];
        return TRUE;
    }

    // Trap up arrow key
    else if (  [textView methodForSelector:command] == [textView methodForSelector:@selector(moveUp:)] )
    {
        if (row==0) return TRUE; //already at the beginning of the list
        NSUInteger newRow = row-1;

        if (newRow>=numRows) return TRUE;
        if (column>= numColumns) return TRUE;

        [tableContentView selectRowIndexes:[NSIndexSet indexSetWithIndex:newRow] byExtendingSelection:NO];
        [tableContentView editColumn:column row:newRow withEvent:nil select:YES];
        return TRUE;
    }

Answer 2

Well it isn't easy but I managed to do it without having to use RRSpreadSheet or even another control. Here's what you have to do:

1. Create a subclass of NSTextView, this will be the field editor. For this example the name MyFieldEditorClass will be used and myFieldEditor will refer to an instance of this class.

2. Add a method to MyFieldEditorClass called "- (void) setLastKnownColumn:(unsigned)aCol andRow:(unsigned) aRow" or something similar, and have it save both the input parameter values somewhere.

3. Add another method called "setTableView:" and have it save the NSTableView object somewhere, or unless there is another way to get the NSTableView object from the field editor, use that.

4. Add another method called - (void) keyDown:(NSEvent *) event. This is actually overriding the NSResponder's keyDown:. The source code should be (be aware that StackOverflow's MarkDown is changing < and > to < and >):

   - (void) keyDown:(NSEvent *) event
   {
       unsigned newRow = row, newCol = column;
       switch ([event keyCode])
       {
           case 126: // Up
               if (row)
               newRow = row - 1;
               break;
   
           case 125: // Down
               if (row < [theTable numberOfRows] - 1)
                   newRow = row + 1;
               break;
   
           case 123: // Left
               if (column > 1)
                   newCol = column - 1;
               break;
   
           case 124: // Right
               if (column < [theTable numberOfColumns] - 1)
                   newCol = column + 1;
               break;
   
           default:
               [super keyDown:event];
               return;
       }
   
       [theTable selectRow:newRow byExtendingSelection:NO];
       [theTable editColumn:newCol row:newRow withEvent:nil select:YES];
       row = newRow;
       column = newCol;
   }
   

5. Give the NSTableView in your nib a delegate, and in the delegate add the method:

   - (BOOL) tableView:(NSTableView *)aTableView shouldEditColumn:(NSTableColumn *) aCol row:aRow
   {
       if ([aTableView isEqual:TheTableViewYouWantToChangeBehaviour])
           [myFieldEditor setLastKnownColumn:[[aTableView tableColumns] indexOfObject:aCol] andRow:aRow];
       return YES;
   }
   

6. Finally, give the Table View's main window a delegate and add the method:

   - (id) windowWillReturnFieldEditor:(NSWindow *) aWindow toObject:(id) anObject
   {
       if ([anObject isEqual:TheTableViewYouWantToChangeBehaviour])
       {
           if (!myFieldEditor)
           {
               myFieldEditor = [[MyFieldEditorClass alloc] init];
               [myFieldEditor setTableView:anObject];
           }
           return myFieldEditor;
       }
       else
       {
           return nil;
       }
   }
   

Run the program and give it a go!