NSTableColumn size to fit contents

Question

I am developing in and against Mac OS X 10.6 (Snow Leopard). When I double-click between two of my NSTableView's column headers, the column on the left autosizes, like you would expect.

I want to provide this in a context menu as well, but it seems there is no publicly accessible function to do this. I've Googled, and looked at the documentation for NSTableView, NSTableHeaderView, and NSTableColumn, but found nothing. I find it hard to believe they wouldn't expose something so useful when they obviously have the code written to do it.

I saw the -[NSTableColumn sizeToFit] method, but that only takes the header's size into account. I would also settle for sending the double-click event to the NSTableHeaderView, but couldn't figure out how to do that, either.

Update - I realized it's important to mention I have an NSArrayController (subclass) providing the data to my table, so I don't have an NSTableViewDataSource on which I could call -[tableView: objectValueForTableColumn: row:]. That is the crux of the problem: each column is bound to a keypath of the array controller and that's how it gets its data, so it can't loop through its contents.

Answer 1

You can get the length of each cell by getting the cells from the column.

NSCell myCell = [column dataCellForRow:i];

Then get the width of the cell.

width = [myCell cellSize].width;

After that you can set the width of the cell as the width of the column.

[column setMinWidth:width];
[column setWidth:width];

Answer 2

The following category on NSTableColumn resizes columns to the same width that double-clicking on the separator would produce.

@implementation NSTableColumn (resize)

- (void) resizeToFitContents
{
    NSTableView * tableView = self.tableView;
    NSRect rect = NSMakeRect(0,0, INFINITY, tableView.rowHeight);
    NSInteger columnIndex = [tableView.tableColumns indexOfObject:self];
    CGFloat maxSize = 0;
    for (NSInteger i = 0; i < tableView.numberOfRows; i++) {
        NSCell *cell = [tableView preparedCellAtColumn:columnIndex row:i];
        NSSize size = [cell cellSizeForBounds:rect];
        maxSize = MAX(maxSize, size.width);
    }
    self.width = maxSize;
}

@end

Answer 3

For view-based table views (OS X 10.7 and later), you have to use the NSTableView method viewAtColumn:row:makeIfNecessary:, and then get the size.

The following code works if your cell view is an NSTextField. For other views you have to figure out the way to get its minimum size.

[tableView.tableColumns enumerateObjectsUsingBlock:
    ^(id obj, NSUInteger idx, BOOL *stop) {
        NSTableColumn* column = (NSTableColumn*) obj;
        CGFloat width = 0;
        for (int row = 0; row < tableView.numberOfRows; row++) {
            NSView* view = [tableView viewAtColumn: idx
                row: row
                makeIfNecessary: YES];
            NSSize size = [[view cell] cellSize];
            width = MAX(width, MIN(column.maxWidth, size.width));
        }
        column.width = width;
    }];
}

Answer 4

I found the following to work for me (written in Swift):

func resizeColumn(columnName: String) {
    var longest:CGFloat = 0 //longest cell width
    let columnNumber = tableView.columnWithIdentifier(columnName)
    let column = tableView.tableColumns[columnNumber] as! NSTableColumn
    for (var row = 0; row < tableView.numberOfRows; row++) {
        var view = tableView.viewAtColumn(columnNumber, row: row, makeIfNecessary: true) as! NSTableCellView
        var width = view.textField!.attributedStringValue.size.width

        if (longest < width) {
            longest = width
        }
    }

    column.width = longest
    viewTable.reloadData()
}

Given a column's identifier as an argument, it finds the cell in that column with the longest content, and resizes the column to fit that content.

Answer 5

I needed to do this very thing and it turned out (for me at least) to be a bit more involved; this isn't perfect but pretty close ;-) p.s. Edited to handle image based cells

#define GBLBIN(x)   [[NSUserDefaults standardUserDefaults] boolForKey:(x)]

- (IBAction)autosizeColumns:(id)sender
{
    NSMutableArray * widths = [NSMutableArray array];
    NSIndexSet * rows = [table selectedRowIndexes];
    NSArray * columns = [table tableColumns];
    BOOL deslectAll = NO;
    NSNumber * col = nil;
    int i, j;

    //  If no row's selected, then select all, the default
    if (![rows count])
    {
        [table selectAll:sender];
        rows = [table selectedRowIndexes];
        deslectAll = YES;
    }

    //  Use the selected rows from which we'll use the columns' formatted data widths
    for (i=[rows lastIndex]; i != NSNotFound; i=[rows indexLessThanIndex:i])
    {
        for (j=0; j<[columns count]; j++)
        {
            NSTableColumn * column = [columns objectAtIndex:j];
            id item = [[table dataSource]
                tableView:table objectValueForTableColumn:column row:i];
            NSCell * cell = [column dataCell];
            float width, minWidth=10;

            //  Depending on the dataCell type (image or text) get the 'width' needed
            if ([cell isKindOfClass:[NSTextFieldCell class]])
            {
                NSFont * font = ([cell font]
                    ? [cell font] : [NSFont controlContentFontOfSize:(-1)]);
                NSDictionary * attrs = 
                    [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
                NSFormatter * formatter = [cell formatter];
                NSString * string = item;

                //  We want a string, as IB would have formatted it...
                if (![item isKindOfClass:[NSString class]])
                    if (formatter)
                        string = [formatter stringForObjectValue:item];
                    else
                        string = [NSString stringWithFormat:@"%@", item];

                width = [string sizeWithAttributes:attrs].width + minWidth;
            }
            else
            {
                //  We have NSButtonCell, NSImageCell, etc; get object's width
                width = MAX(minWidth,[[cell image] size].width);
            }

            //  First time seeing this column, go with minimum width
            if (j == [widths count])
            {
                [widths addObject:[NSNumber numberWithFloat:minWidth]];
            }
            col = [widths objectAtIndex:j];
            width = MAX([col floatValue], width);
            [widths replaceObjectAtIndex:j withObject:[NSNumber numberWithInt:width]];
        }
    }

    //  Now go resize each column to its minimum data content width
    for (j=0; j<[widths count]; j++)
    {
        NSTableColumn * column = [columns objectAtIndex:j];
        float width = [[widths objectAtIndex:j] floatValue];

        if (GBLBIN(@"debug"))
        {
            NSLog(@"col:%d '%@' %.f", j, [column identifier], width);
        }
        [column setWidth:width];
    }

    //  Undo select all if we did it
    if (deslectAll)
    {
        [table deselectAll:sender];
    }
}