Re: If Array Controller is empty, how to populate pop-up list?
Hi Ken, Thanks for your tips. We're closer I think. I took off the Selected Index binding and instead bound the Selected Value to ArrayController-selection-name. I'm probably binding it wrong though, because I haven't quite gotten it to work yet. I think what you say makes sense, about the selection objects and enabled properties. I have a string in all three bindings' No Selection Placeholder for the popup bindings (Content, Content Values, and Selected Value), but instead, when the array controller is empty, the popupbutton is both disabled and empty. Conditionally Sets Enabled is checked AND Avoid Empty Selection is checked, but, no dice... You said this is what worked for you? :/ Jenny With some experimentation, I discovered the following: I bound the pop-up's content to the array controller's arrangedObjects. I bound its Selected Value or Selected Object (but not Selected Index) to the array controller's selection with an appropriate model key path. For the content binding, I set a No Selection Placeholder string. Then, whenever the array controller had no selection, the pop-up showed the placeholder string. If the Selected Value binding's Conditionally Sets Enabled option is on (the default), then the pop-up is disabled when there's no selection in the array controller. This is sort of bad if the controlled array is not empty but the array controller has no selection. In that case, the pop-up shows the placeholder but is disabled, so the user can't access the other items in the pop-up. However, the array controller won't have no selection if its Avoid Empty Selection property is enabled (again, the default). With that property enabled, the pop-up shows the placeholder and is disabled only if there's nothing in the controlled array. If there are objects in the array, then the array controller has a selection and the pop-up shows it and is enabled. So, Conditionally Sets Enabled on the pop-up's Selected Value or Object binding, plus Avoids Empty Selection on the array controller works well. Turning both of those off makes for a functional but possibly strange interface; when the array is non-empty but the array controller has no selection, the pop-up shows the placeholder but is enabled and also contains the normal items. I hope that helps. Cheers, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
On Jan 17, 2010, at 4:36 PM, Jenny M wrote: Thanks for your tips. We're closer I think. I took off the Selected Index binding and instead bound the Selected Value to ArrayController-selection-name. I'm probably binding it wrong though, because I haven't quite gotten it to work yet. I think what you say makes sense, about the selection objects and enabled properties. I have a string in all three bindings' No Selection Placeholder for the popup bindings (Content, Content Values, and Selected Value), but instead, when the array controller is empty, the popupbutton is both disabled and empty. Conditionally Sets Enabled is checked AND Avoid Empty Selection is checked, but, no dice... You said this is what worked for you? :/ Yes, that sounds like what I did. However, on thinking some more about this, I think I was on the wrong track. The selection value or object bindings of the pop-up would tend to set the bound-to property to whatever was selected in the pop-up. So, if you bind the selected value to ArrayController.selection.name, when the pop-up selection changes, it would attempt to set the name property of the object selected in the ArrayController. That's not what you want. Although the Selected Index of the pop-up may sensibly be bound to the array controller's selection index, which will properly result in the selection tracked by the array controller matching the selection in the pop-up, that doesn't appear to trigger the No Selection placeholder of the content bindings, as you've discovered. Basically, the array controller doesn't return the NSNoSelectionMarker marker for its selectionIndex property, it just returns NSNotFound. So, try this: make a property on your window controller, app controller, or other appropriate coordinating controller (not the array controller, which is a mediating controller; probably this would be the same controller which provides the content for the array controller). This new property will hold the state which the pop-up represents in the GUI. Bind either the pop-up's selected object or selected value, whichever makes most sense for your design, to this property. This property can be set when the array has contents, but when the array is empty it can return the NSNoSelectionMarker instead of, for example, nil. That should be sufficient to trigger both the No Selection Placeholder and the Conditionally Sets Enabled bindings, leaving the pop-up disabled and showing the placeholder. Alternatively, if the new property is bound to the pop-up's selection value, you can have it just directly return the placeholder when the array is empty. To disable the pop-up, you can bind its Enabled binding to arraycontroller.arrangedobjec...@count. Since the value of this new property changes depending on whether or not the array has contents, you'll want to tell KVO that it's dependent on the array property (+keyPathsForValuesAffectingKey). Regards, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
On Jan 14, 2010, at 4:09 PM, Jenny M wrote: I have an Array Controller whose objects are displayed in an NSPopUpButton. However, what can I do if the array controller becomes empty? If I delete all the objects, or if the window starts up with an empty array controller, I'd like for the list to then have a null element that says No objects. Once an object is added, it should go away. But if I choose Insert null placeholder in the pop-up options, the null placeholder is ALWAYS there, which is not good. Well, this part is as expected. That's what the null placeholder is for. It's not a way to represent when the array controller has no objects. It's a way for the pop-up to give the user the option of selecting none of the objects from the array controller. Is there a way to do this in IB, or is this a thing I should code? And if so, how can I make sure the method is called whenever there is a change to the array controller? With some experimentation, I discovered the following: I bound the pop-up's content to the array controller's arrangedObjects. I bound its Selected Value or Selected Object (but not Selected Index) to the array controller's selection with an appropriate model key path. For the content binding, I set a No Selection Placeholder string. Then, whenever the array controller had no selection, the pop-up showed the placeholder string. If the Selected Value binding's Conditionally Sets Enabled option is on (the default), then the pop-up is disabled when there's no selection in the array controller. This is sort of bad if the controlled array is not empty but the array controller has no selection. In that case, the pop-up shows the placeholder but is disabled, so the user can't access the other items in the pop-up. However, the array controller won't have no selection if its Avoid Empty Selection property is enabled (again, the default). With that property enabled, the pop-up shows the placeholder and is disabled only if there's nothing in the controlled array. If there are objects in the array, then the array controller has a selection and the pop-up shows it and is enabled. So, Conditionally Sets Enabled on the pop-up's Selected Value or Object binding, plus Avoids Empty Selection on the array controller works well. Turning both of those off makes for a functional but possibly strange interface; when the array is non-empty but the array controller has no selection, the pop-up shows the placeholder but is enabled and also contains the normal items. I hope that helps. Cheers, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
If Array Controller is empty, how to populate pop-up list?
Hi all, I have an Array Controller whose objects are displayed in an NSPopUpButton. I can add and remove objects, and they refresh automatically in the box as expected. However, what can I do if the array controller becomes empty? If I delete all the objects, or if the window starts up with an empty array controller, I'd like for the list to then have a null element that says No objects. Once an object is added, it should go away. But if I choose Insert null placeholder in the pop-up options, the null placeholder is ALWAYS there, which is not good. Is there a way to do this in IB, or is this a thing I should code? And if so, how can I make sure the method is called whenever there is a change to the array controller? Thanks in advanced... ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
Uhh, okay so there's another problem I discovered. Below the popupmenu, I have two text fields that are supposed to show two of the attributes of the selected object (in the array controller). But changing the selection in the popupmenu does NOT change the selected item in the array controller. How do I wire the two together such that selecting a different value in the nspopupmenu also changes the selected object in the array controller? Right now the NSPopUpMenu has the bindings set like so: - Content: ArrayController.arrangedObjects - Content Values: ArrayController.arrangedObjects.name Any ideas what else I need to set?? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
Cancel Message #2 - I figured out how to change the selected object. I added one more binding - I bound the NSPopUpButton Selected Index to ArrayController.selectionIndex. However, message #1 still stands - how do I implement a placeholder object only when the array is empty?? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
On 15/01/2010, at 1:18 PM, Jenny M wrote: However, message #1 still stands - how do I implement a placeholder object only when the array is empty?? In your content binding for the popup button in Interface Builder, check the Inserts Null Placeholder checkbox and enter a value in the Null Placeholder field. -- Rob Keniger ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
Like I mentioned previously - when I do that, it stays there even after an object has been added, which is not what I'm aiming for. I only want it to appear when empty. In your content binding for the popup button in Interface Builder, check the Inserts Null Placeholder checkbox and enter a value in the Null Placeholder field. -- Rob Keniger ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: If Array Controller is empty, how to populate pop-up list?
On 15/01/2010, at 4:24 PM, Jenny M wrote: Like I mentioned previously - when I do that, it stays there even after an object has been added, which is not what I'm aiming for. I only want it to appear when empty. Ah, sorry, I didn't see that in your original post. -- Rob Keniger ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
