context menu based on NSTableView cell

Question

I would like to place a context menu onto a NSTableView. this part is done. What I would like to do is to show different menu entries based on the content of the right clicked cell, and NOT show the context menu for specific columns.

this is:

column 0, and 1 no context menu

all other cells should have the context menu like this:

first entry: "delete " samerow.column1.value
second entry: "save " samecolumn.headertext

-EDIT-

the one on the right is how the context menu is supposed to look like for any given cell.

Hackbut

Answer 1

Theres a delegate for that! - No need to subclass

In IB if you drag an NSTableView onto your window/view you'll notice that theres a menu outlet for the table.

So a very easy way to implement the contextual menu is to connect that outlet to a stub menu and connect the delegate outlet of the menu to an object which implements the NSMenuDelegate protocol method - (void)menuNeedsUpdate:(NSMenu *)menu

Normally the delegate of the menu is the same object which provides the datasource/delegates to the table but it might also be the view controller which owns the table too.

Have a look at the docs for more info on this

Theres a bundle of clever stuff you can do in the protocol but a very simple implementation might be like below

#pragma mark tableview menu delegates

- (void)menuNeedsUpdate:(NSMenu *)menu
{
NSInteger clickedrow = [mytable clickedRow];
NSInteger clickedcol = [mytable clickedColumn];

if (clickedrow > -1 && clickedcol > -1) {



   //construct a menu based on column and row   
   NSMenu *newmenu = [self constructMenuForRow:clickedrow andColumn:clickedcol];

   //strip all the existing stuff       
   [menu removeAllItems];

   //then repopulate with the menu that you just created        
   NSArray *itemarr = [NSArray arrayWithArray:[newmenu itemArray]];
   for(NSMenuItem *item in itemarr)
   {
      [newmenu removeItem:[item retain]];
      [menu addItem:item];
      [item release];
   }        
}

}

And then a method to construct the menu.

-(NSMenu *)constructMenuForRow:(int)row andColumn:(int)col
{

    NSMenu *contextMenu = [[[NSMenu alloc] initWithTitle:@"Context"] autorelease];

NSString *title1 = [NSString stringWithFormat:@"Delete %@",[self titleForRow:row]]; 

NSMenuItem *item1 = [[[NSMenuItem alloc] initWithTitle:title1 action:@selector(deleteObject:) keyEquivalent:@""] autorelease];
    [contextMenu addItem:item1];
    //
NSString *title2 = [NSString stringWithFormat:@"Save %@",[self titleForColumn:col]];    

NSMenuItem *item2 = [[[NSMenuItem alloc] initWithTitle:title1 action:@selector(saveObject:) keyEquivalent:@""] autorelease];
    [contextMenu addItem:item2];

return contextMenu;
}

How you choose to implement titleForRow: and titleForColumn: is up to you.

Note that NSMenuItem provides the property representedObject to allow you to bind an arbitrary object to the menu item and hence send information into your method (e.g deleteObject:)

EDIT

Watch out - implementing - (void)menuNeedsUpdate:(NSMenu *)menu in your NSDocument subclass will stop the Autosave/Versions menu that appears in the title bar appearing in 10.8.

It still works in in 10.7 so go figure. In any case the menu delegate will need to be something other than your NSDocument subclass.

Frowzy

thanks! will try it today! is this method called automatically or do i have to call it on rightclick? thanks – Hackbut

Long time since I wrote it , but it should just happen automagically due to menu outlet being connected – Frowzy

thanks! trying right now, but i am having trouble understanding this: ` //let your data object provide the menu NSMenu *newmenu = [thing menuThatMyThingProvides]; ` – Hackbut

It just means let the referenced data object construct an arbitrary menu and pass it back to the method. However in your case you probably want to construct a menu based on clickedRow] & clickedColumn] . Ill make an edit – Frowzy

sorry for the late reply, had the dog on surgery.. thanks it works, except for 2 minor problems: 1) the context menu is grayed out... any idea why? maybe because for now i have set action:nil? 2) when i click where i am supposed to click the menu is properly generated. when i click outside where i am supposed to click the menu appears as the last menu i used. can the menu be disabled if i am outside the desired cells? thanks! – Hackbut

first issue is due to the nil selector . when you implement the method on the target the item will come alive. second issue - try stripping the menu but not re-adding items for those row/col combination or implement the delegate - (NSInteger)numberOfItemsInMenu:(NSMenu *)menu and return 0 when needed – Frowzy

thank you! accepted! you deserve the +50! :) have a nice weekend! – Hackbut

do you by chance also know how to add the separator line to a menu programmatically? – Hackbut

It's a class method that NSMenuItem provides , check the API docs. separatorItem... – Frowzy

could you please tell me how to pass on variables to the methos specified in the @selecotr ? – Hackbut

Use the representedObject property of NSMenuItem to carry the information. It can be anything as it has a type of id. The menu item will be the message sender and from its representedObject you can carry info across the event. – Frowzy

Hello Warren. This is Sid. The solution above worked excellent for me. I had implemented this solution of yours few months back. But, then I am reported with few issues now. And the only problem I am facing is, This Menu don't get popped up on Control + Click neither CMD + Click. User has to double tap on trackpad along with Control OR Cmd clicked. Why is that so ? Am I missing something ? – Assemble

Sorry, no idea why your code is not working with this method. I use the pattern in both tableviews and outline views and have not seen that effect. As a guess maybe you have custom views/view based cells which are sucking up the single-click event . – Frowzy

I know this is an older post I'm replying to, so forgive me, but how did you make that stub menu, the one called "Item 1" in the image? Ahh- found it, they changed it so the menu has to be dropped into the Scene, and gets a nice little connector arrow of its own. – Lecia

Answer 2

Edit: The better way to do this than the below method is using delegate as shown in the accepted answer.

You can subclass your UITableView and implement menuForEvent: method:

-(NSMenu *)menuForEvent:(NSEvent *)event{
    if (event.type==NSRightMouseDown) {
        if (self.selectedColumn == 0 || self.selectedColumn ==1) {
            return nil;
        }else {
            //create NSMenu programmatically or get a IBOutlet from one created in IB
            NSMenu *menu=[[NSMenu alloc] initWithTitle:@"Custom"];

            //code to set the menu items

            //Instead of the following line get the value from your datasource array/dictionary
            //I used this as I don't know how you have implemented your datasource, but this will also work
            NSString *deleteValue = [[self preparedCellAtColumn:1 row:self.selectedRow] title]; 

            NSString *deleteString = [NSString stringWithFormat:@"Delete %@",deleteValue];
            NSMenuItem *deleteItem = [[NSMenuItem alloc] initWithTitle:deleteString action:@selector(deleteAction:) keyEquivalent:@""];
            [menu addItem:deleteItem];

            //save item
            //similarly 
            [menu addItem:saveItem];

            return menu;
        }
    }
    return nil;
}

That should do it. I haven't tried out the code though. But this should give you an idea.

Drudge

Not a good idea, as it usually conflicts with the MVC pattern. If you need values from the table view you shouldn't implement the menu creation in the view but your controller. – Worsham

Answer 3

I also tried the solution posted by Warren Burton and it works fine. But in my case I had to add the following to the menu items:

[item1 setTarget:self];
[item2 setTarget:self];

Setting no target explicitly causes the context menu to remain disabled.

Cheers!

Alex

PS: I would have posted this as a comment but I do not have enough reputation to do that :(

Heady

Answer 4

Warren Burton's answer is spot on. For those working in Swift, the following example fragment might save you the work of translating from Objective C. In my case I was adding the contextual menu to cells in an NSOutlineView rather than an NSTableView. In this example the menu constructor looks at the item and provides different options depending on item type and state. The delegate (set in IB) is a ViewController that manages an NSOutlineView.

 func menuNeedsUpdate(menu: NSMenu) {
    // get the row/column from the NSTableView (or a subclasse, as here, an NSOutlineView)
    let row = outlineView.clickedRow
    let col = outlineView.clickedColumn
    if row < 0 || col < 0 {
        return
    }
    let newItems = constructMenuForRow(row, andColumn: col)
    menu.removeAllItems()
    for item in newItems {
        menu.addItem(item)
        // target this object for handling the actions
        item.target = self
    }
}

func constructMenuForRow(row: Int, andColumn column: Int) -> [NSMenuItem]
{
    let menuItemSeparator = NSMenuItem.separatorItem()
    let menuItemRefresh = NSMenuItem(title: "Refresh", action: #selector(refresh), keyEquivalent: "")
    let item = outlineView.itemAtRow(row)
    if let block = item as? Block {
        let menuItem1 = NSMenuItem(title: "Delete \(block.name)", action: #selector(deleteBlock), keyEquivalent: "")
        let menuItem2 = NSMenuItem(title: "New List", action: #selector(addList), keyEquivalent: "")
        return [menuItem1, menuItem2, menuItemSeparator, menuItemRefresh]
    }
    if let field = item as? Field {
        let menuItem1 = NSMenuItem(title: "Delete \(field.name)", action: #selector(deleteField), keyEquivalent: "")
        let menuItem2 = NSMenuItem(title: "New Field", action: #selector(addField), keyEquivalent: "")
        return [menuItem1, menuItem2, menuItemSeparator, menuItemRefresh]
    }
    return [NSMenuItem]()
}

Barley

Answer 5

As TheGoonie mentioned, I also got the same experience- context menu items were remained disable. However the reason for items being disabled is 'Auto Enables Items' property.

Make 'Auto Enables Items' property to off. or set it programmatically to NO.

[mTableViewMenu setAutoenablesItems:NO];

Tarrsus

Answer 6

Here is an example setting up an NSOutlineView programmatically within a view controller. This is all the plumbing you need to get the context menu up and running. No subclassing required.

I had previously subclassed NSOutlineView to override menu(for event: NSEvent), but came to a simpler set-up with the help of Graham's answer here and Warren's answer above.

class OutlineViewController: NSViewController 
{
    // ...
    var outlineView: NSOutlineView!
    var contextMenu: NSMenu! 

    override func viewDidLoad()
    {
        // ...
        outlineView = NSOutlineView()
        contextMenu = NSMenu()
        contextMenu.delegate = self
        outlineView.menu = contextMenu
    }
}

extension OutlineViewController: NSMenuDelegate
{
    func menuNeedsUpdate(_ menu: NSMenu) {

        // clickedRow catches the right-click here 
        print("menuNeedsUpdate called. Clicked Row: \(outlineView.clickedRow)")

        // ... Flesh out the context menu here
    }
}

Cleptomania

Answer 7

This is the easiest method for a custom/dynamic NSMenu I found, that also preserves the system look (the blue selection border). Subclass NSTableView and set your menu in menu(for:).

The important part is to set the menu on the table view, but return the menu from its super call.

override func menu(for event: NSEvent) -> NSMenu? {
    let point = convert(event.locationInWindow, from: nil)
    let clickedRow = self.row(at: point)
    var menuRows = selectedRowIndexes

    // The blue selection box should always reflect the
    // returned row indexes.
    if menuRows.isEmpty || !menuRows.contains(clickedRow) {
        menuRows = [clickedRow]
    }

    // Build your custom menu based on the menuRows indexes
    self.menu = <#myMenu#>

    return super.menu(for: event)
}

Jaeger