Re: Sizing table columns to fit data - a solution looking for suggestions
Re: Sizing table columns to fit data - a solution looking for suggestions
- Subject: Re: Sizing table columns to fit data - a solution looking for suggestions
- From: Corbin Dunn <email@hidden>
- Date: Fri, 30 Jan 2009 08:10:29 -0800
Below is a reasonably generic Cocoa solution for implementing this
behavior.
The tableView I developed this for uses an arrayController with
individual column bindings; not the old school -dataSource methods
for handling the data.
This code should exist in tableView's delegate.
This solution handles both strings and images.
I don't like the reliance on calling the arrayController directly
but for now it serves my purpose
Overall, I would do it slightly differently; I would subclass
NSTAbleHeaderView, figure out what column needs it to be autoresized
and when (ie: double click), and then ask the delegate (optionally)
what size it wants. But, I would make a default implementation based
on -cellSize (possibly doing a monte carlo simulation on the number of
rows, if there were a lot of rows, to help with performance).
Here are comments on your version:
I am interested in both criticisms and improvements - both will
serve the Cocoa community..
- (void)tableView:(NSTableView *)tableView
mouseDownInHeaderOfTableColumn:(NSTableColumn *)tableColumn {
First off, don't use the 'tableView:' prefix for your own delegate
methods. Consider what would happen if AppKit introduced the same
delegate method in a future release. Well, I can tell you from
experience that it won't be good. So, please make it something like
"scTableView:...".
NSEvent *event = [NSApp currentEvent];
if ([event clickCount]==2) {
NSPoint location = [event locationInWindow];
NSTableHeaderView *header = [tableView headerView];
location = [header convertPoint:location fromView:nil];
if (location.x>=2.0) location.x-=2; // offset point 2 pixels
'cause the 'split' cursor is a little 'permissive'
NSTableColumn *thisColumn = [[tableView tableColumns]
objectAtIndex:[header columnAtPoint:location]];
NSString *maxStr = @"";
id thisObj;
NSCell *dCell;
float newWidth, maxStringWidth = 0.0 ,maxImageWidth = 0.0;
Use CGFloat not float.
// me don't like the next line
NSArray *theValues = [[myArrayController arrangedObjects]
valueForKey:[thisColumn identifier]]; //dump the tableColumn values
to an array
Instead of this hardcoded access, do this (sorry, not complete, but
you should understand the idea):
CGFloat maxWidth = 0;
for (NSInteger i = 0; i < tableView.numberOfRows; i++) {
NSCell *cell = [tableView preparedCellAtRow:i column:column];
NSSize size = [cell cellSize];
if (size.width > maxWidth) maxWidth = size.width;
}
[tableColumn setWidth:maxWidth];
The code above is *much* more generic. Note that it doesn't consider
the indentation for outlineviews.
if ([thisColumn width] != newWidth) {
[thisColumn setWidth:newWidth];
Setting the width in a loop is not good for performance; it might
cause the table to relayout a lot of times.
Anyways, as usual, it never hurts to log feature requests for AppKit
to do this for you.
corbin
} else {
//if already max then here double-click sets to half max!
(maybe NOT do this if images were found?)
[thisColumn setWidth:newWidth/2.0];
}
}
}
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