Make NSTableView contents of a column conditionally visible?

Scripting Forums AppleScriptObjC and Xcode
#1

Hello,

After trying a number of binding combination (which all fail) I wanted to know if it is possible to:

In a NSTableView, make the contents of one column visible if, and only if, its row is selected by user.

I never seen this before, I’m not sure it conforms to Apple’s Interface Guidelines, but it’s only one specific feature of my app, not the general behavior…

Thanks!

#2

Hi,

you can control the drawing of a cell with the
tableView:willDisplayCell:forTableColumn:row:
delegate method

Personally I wouldn’t do that. It looks like a misoperation

#3

Mmmh. I know. Everytime it begins to be difficult to find a method in the docs, it means I’m fighting against the framework. No good.

But how would you do if the user has to guess the contents of a cell before looking at it? Ok, I could add a button like “Reveal solutions” to show them all (making the column visible, for example), but it’s hard for a user to guess, say, 15 solutions before controlling them.

Ok, thank you for your answer. I have been warned. :roll eyes:

Regards,

#4

the normal way to display filtered content is to use predicates like the spotlight search result table view

#5

Ok, so I have to use current application’s NSPredicate to create, say, a isTheLineSelected predicate (which returns a boolean value) and then use

myTableView’s setFilterPredicate_(isTheLineSelected) to activate it, and
setFilterPredicate_(missing value) to clear it. So far, so good.

But does the tableView send a message to the predicate at each cell? where do I actually evaluate the condition? Oh, it does not look simple.

#6

Another way to do this might be to have a blank answer in all the rows of the answer column, like “--------”, and then switch out the dashes for the answer. The following example does this by copying the value of the “ans” field to the “blocked” field when the user selects a row. It also “covers up” the previous answer and shows a new answer when you change to a new row (this can be disabled by commenting out the first and last lines of the tableViewSelectionDidChange: method).

script AppDelegate
	property parent : class "NSObject"
    property theData:missing value
    property lastSel:-1
    
	on applicationWillFinishLaunching_(aNotification)
		setTheData_({{ques:"First Person Singular",ans:"I",blocked:"------"}, ¬
        {ques:"First Person Plural",ans:"We",blocked:"------"} ,¬
        {ques:"Second Person Singular",ans:"You",blocked:"------"} ,¬
        {ques:"Third Person Plural",ans:"They",blocked:"------"}})
        --log theData
	end applicationWillFinishLaunching_
    
    on tableViewSelectionDidChange_(aNote)
        if lastSel is not -1 then theData's objectAtIndex_(lastSel)'s setValue_forKey_("------","blocked")
        set sel to aNote's object's selectedRow()
        theData's objectAtIndex_(sel)'s setValue_forKey_(theData's objectAtIndex_(sel)'s valueForKey_("ans"),"blocked")
        set lastSel to sel
    end
end script

The answer column is bound to array controller.arrangedObjects.blocked, and the script is the delegate for the table view.

Ric

#7

Once again, thanks, Ric.

I used a new “Peeping” column to transfer the data stored into a hidden “Solution” column, giving this:

on tableViewSelectionDidChange_(aNotification)
        set sel to aNotification's object's selectedRow()
        set theData to gVerbFormsController's arrangedObjects
        if selectedLine is not -1 then theData's objectAtIndex_(selectedLine)'s setValue_forKey_("","vPeep")
        set peeping to theData's objectAtIndex_(sel)'s valueforKey_("vSol")
        theData's objectAtIndex_(sel)'s setValue_forKey_(peeping,"vPeep")
        set selectedLine to sel
end tableViewSelectionDidChange_

I had to ask my controller to give back its data, as I use a controller (don’t even know why, in fact). Well, I’m sure there is a much more simple solution, using Applescript record instead of key/value of NSDic.

Anyway, it’s working perfectly, that was exactly what I wanted. I’m glad to have a simple solution, of course maybe I would have learned something about predicates using Stefan’s suggestion.

Thanks again to both of you!

EDIT:

Yes it was.

            if oldSelection is not 0 then set (item oldSelection of gVerbFormsList)'s vPeep to ""
            set newSelection to aNotification's object's selectedRow()+1 -- Applescript is 1-based, Cocoa is 0-based.
            set newLine to item sel of gVerbFormsList
            set newLine's vPeep to newLine's vSol -- could have done a single line but no :)
            set oldSelection to newSelection