I have a main NSArrayController bound to an NSTableView with each row containing an instance of MyObject. MyObject has about 30 properties, but the NSTableView only has 5 columns (to show the most important properties). When a row (or more) is selected I have another NSTableView (a detail view) which shows all the properties, one per row. The detail table has two columns, one for the property name and one for the property value.
I have this working right now but my detail NSTableView uses a data source rather than bindings. This works fine as long as I notify my detail controller (which manages the data source) of a change in the main selection so that it can reload the detail table.
While it is easy to detect a change in selection, it is harder to detect a change in one of the properties of a selected object. I see elsewhere on StackOverflow, that one way to do this is to have a dummy property and use keyPathsForValuesAffectingValueForKey. Does this work well performance-wise?
Is there some other/better way to build my detail NSTableView/NSArrayController so that each row represents one property of the selected objects on the main NSTableView/NSArrayController? I'd like to use bindings if possible.
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im a osx-dev noob that is trying to build an application with three table views that will show the content of a core data store entity. But each table view is filtered on the attribute "status" of the entity.
the problem occurs when i also want to show the selected entity in textfields. I'm using three different array controllers with different fetch predicates. But in a textfield i can only bind the value to one array controller.
should i ditch the bindings and do it all programaticly or is there a simple solution to this? :)
here is an screenshot so you can grasp my app description.
Keep bindings to populate the text fields if it satisfies what you want to do with this GUI. I'd add an NSObjectController to control the one entity those fields represent. If you want the user's changes to those fields persisted, bindings are still awesome.
But I think with three tables that might control what's displayed in the text fields, you're going to need to have some sort of non-binding glue code that determines which of the tables wins. You can probably do everything you want by implementing some of the NSTableViewDelegate protocol.
If the text fields should display the last entity that the user clicked in any of the tables, simply have each table call the same tableViewSelectionDidChange delegate function. All three tables could have the same delegate. You can then call setContent on the NSObjectController from that function.
You could also use similar glue code to prevent more than one selection in any of the three tables, by having the same delegate function deselect everything in the other tables either through the view or the controller. But that's up to you and needs consideration of whether you want multiple selection, etc.
I'm attempting to use Cocoa bindings to populate an NSTableView using Core Data entities. I've arrived at a point where I'm boggled by the behavior of my application. The array controller is in "Entity Name" mode and is using the my "Song" entity.
The table view I am attempting to load the data into has two columns: one for the song name and another for the artist name (the artist is another entity which has a relationship to a song). Through Interface Builder, I have been able to successfully bind the array controller to the table, and setup bindings for the two columns. However, for some reason, one of the columns' bindings is working perfectly (artist name) while the other is not populating at all (song name).
I have gone through each view in the Document Outline and ensured that both columns are configured in exactly the same manner. I've attached some screenshots below showing the binding setup in Interface Builder.
Binding on the NSTableColumn representing the Song Title
Binding on the NSTextField within the NSTableCellView (the one that is not working)
Binding on the NSTextField for Artist Name (the one that is working)
The final (non-functioning) result
Is there an obvious reason why this approach is not working? Any help would be greatly appreciated. I can also provide any additional information that may be needed to answer this question.
It appears you are using a "view" based NSTableView as opposed to the older "cell" based. Each have a different configuration for bindings. In a view based table view you have to bind the tableview content to the array controllers arrangedObjects (see below), you don't have to deal with the individual column bindings that is for cell based table views.
Your remaining bindings look fine.
Just a wild guess. Since you're speaking of the Song entity.
Can it be that you have to bind the song name to objectValue.song.title?
If 'Artist' isn't just an attribute of the 'Song' entity but an entity itself (which it must likely be if it has a relationship to 'Song') then I think you need to have a separate array controller connected to that column in order for it to work properly.
I have inspector view and because it contains a lot of UI I want to explore cocoa bindings to connect it to the model. The inspector view will update depending on the currently selected object in an outline view and the inspector view displays controls to alter properties (like colour, name, shape etc.) that can be changed.
This works well when only one row in the outline view is selected because the view has a one-to-one relationship with the model object. However, there are two special cases that I want to be able to catch:
Empty selection
If no items in the outline view are selected I want to display a special "No items selected view" placeholder view.
Multiple selection
If multiple items are selected I can either display a "Multiple items selected view" placeholder view or I can decide to let the changes apply globally to all selected model objects.
My question is how can these special cases be caught when using bindings? Moreover, how can I do behaviour "A" when there is an empty selection and behaviour "B" when there is a multiple section. This sort of thing is trivial when using target/action because you can just code the logic into the action method.
Bindings seem great when propagating changes to values but I'm unsure how to go about implementing bindings that require different decisions based on current selection state.
I'm trying to create a Mac OS Core Data application that has an array of parent objects (called Levels) each of which contains a collection of child objects (called Blocks) via a one-to-many relationship. I have a table view successfully controlling the array of levels, and a custom view object that draws the blocks graphically based on positions held in x and y properties of my Block model class. I can add blocks to the currently selected level, remove them, select and move them around in the custom view, and have bound text fields to various other properties of the Block class which I can use to edit those values. All of this information is successfully saved and restored to and from the core data repository with no issues output to the debugger. Wonderful. I've used an NSArrayController for the Levels and another for the Blocks that is bound to the current selection of the Levels array controller, in what I've read is a pretty standard way.
Now, my Block class is actually an abstract class, and what I actually instantiate are various child classes of Block (eg RedBlock, GreenBlock, BlueBlock classes). Each sub-class has a separate set of properties that only apply to that type of block (so RedBlock has a "text" property that none of the others have, BlueBlock has an integer "value" property, etc). I want to create an inspector that will change depending on the type of the Blocks that are currently selected in my custom view. To try this, before I start creating subviews for each type of Bock, I have created a text field that I want to bind to the currently selected RedBlock's "text" property, preferably showing nothing when Blocks of other kinds are selected. This is where I'm stuck. I've added another NSArrayController in Entity mode with RedBlock specified as it's type so I can bind to the "text" property, and tried adding a filter predicate based on the class type. I've also tried various other configurations and bindings, but I'm either getting exceptions, or corrupt values in the text field that I bind to that controller, or other weird bugs and general brokenness.
I've googled around for an example of an inspector that can cope with a heterogenous array of objects (as that's essentially what I'm trying to do) but so far no luck.
So, my question is - am I going about this the right way? Should I be trying to create an NSArrayController that filters the selected items in my Blocks array controller somehow? If so, should that be straightforward or is there some trick that I've missed? If not, what is the best way to do this?
This approach should work, provided you limit the inspector to displaying view which bind to properties which apply to the entire selection. You don't need a second array controller.
To test the simple example, try creating a data set with only blocks, see that your bound control loads without raising exceptions, and that it updates the object correctly.
Once that is working, create separate views for each type, and display and hide them when the selection will change. Again, if you have a heterogenous selection, hide them all.
I've got a table one column of which uses an NSPopUpButtonCell. Try as I might, I can't seem to figure out the way to properly bind everything the way I want it. Here's what I'm trying to do:
I have an NSArrayController plucking items from a managed object context, called 'Field Values'. This is to be used to populate the popup menu for each item (i.e. the list of available choices). I can bind this by selecting the cell in IB and binding its content/objects/values to 'Field Values'.arrangedObjects and 'Field Values'.arrangedObjects.name as appropriate (to get the represented object and the visible title).
I then want to bind the column in such a way that the selected value in each row comes from an array in my controller class, again made visible (and only edited through) another NSArrayController.
So far I've managed to set it up so that every popup menu contains the list of available fields, and that the default value is selected in each of them. Actually selecting an item has no effect, however— it just snaps back to its initial value. I've also managed to find some other variations on this, such as the menu being populated with the selected values, or containing the name of all available values, and the selection containing the -description of the 'none' value I added.
I'm sure I'm missing something fairly simple, but I'm not sure what it is. Presumably there's some subtlety I've missed in how to bind this sort of data (i.e. the Content vs. Content Object vs. Content Value things), but I'm damned if I can see it right now.
Many thanks in advance :o)
I've got a similar set up with a table view, although the data source isn't Core Data based, but I saw one thing you might double check that could be a subtle difference. In my setup for the table column, I have the table column itself bound via content, contentValues, and selectedObject. However, it looks like it's also possible to do the bindings on the actual NSPopUpButtonCell instead. Perhaps it works when the bindings are on the table column, but not when they're on the actual cell? Anyway, there's one thing that might be worth looking into.
Never bind to scroll view, table view or cell.
However, ever bind to table columns.
Watch the title of the Inspector window to be certain of what you're binding.