Inserting image into NSTableView using bindings

Question

I've an NSTableView bound to an NSArrayController with two columns. One column is bound to the arranged objects of the array controller and displays a string.

I'd like to display an image in the other column, but I just can't make it work. I've dragged an NSImageCell to the column and set the image by hand but it won't show up at runtime. I've double checked and the image is in my resources directory.

Am I missing something? What else should I do to make that image appear?

Answer 1

So you want to have the same image appear for each row? Is that why you're setting it "by hand"? For that, you can mix NSTableViewDataSource methods with bindings. The idea is your string column will be bound as usual, but your image column isn't bound. It has its identifier set (like "imageColumn"). You then use numberOfRowsInTableView: and tableView:objectValueForTableColumn:row: to provide the array controller's object count (so it has the right number of rows) and simply always return your static image when it asks for the value for the right column (checking the id for your "imageColumn"), returning nil otherwise.

If the image is not static (that is, you want to use it as an indicator of some kind) you can use the above method (return some image based some value) OR bindings. To use Bindings, you might add a property to whatever class your array controller is holding, like "status" (a number). You'll then use a custom NSValueTransformer that transforms the status number into a corresponding image. Your column will be bound to the array controller's arrangedObjects.status, using the value transformer (see NSValueTransformer for instructions for use - you have to register it, then use its name). The result is an image in your column that corresponds to a certain status.