I am using NSTreeController with NSOutlineController to display contents in 1parent-1child hierarchy.
My structure is like this:
- parent
- child
- parent
- child
Now when user press a refresh button, I want to remove all the nodes and refill it again.
[[treeController arrangedObjects] removeAllItems];
[[treeController arrangedObjects] removeAllObjects];
but nothings seems to be working.
I guess binging NSTreeController with NSArrayController should help but I really don't know steps to bind -NSArrayController-NSTreeController-NSOutlineController.
I do it all the time with unbound lists.
Simple to clear the list:
[treeController setContent:nil];
From the documentation for the content property:
The value of this property can be an array of objects, or a single root object. The default value is nil.
If your content is an array (presumably an NSMutableArray), then
[treeController.content removeAllObjects];
would be appropriate. Setting it to nil removes the underlying container. If your content is a single object, then
treeController.content = nil;
is the correct choice.
Related
Searched entire Internet but couldn’t find the modern solution for my problem.
I want to use NSObjectController in pair with Core Data through Cocoa Bindings and struggle to set it up properly. Worth noting that I’m using latest version of Xcode and Swift.
What I’ve done:
For testing purposes I’ve done the following:
Created an macOS app with “Use Core Data” option selected (the app is not document based);
Dragged 2 NSTextFields into the Storyboard Dragged NSObjectController to the view controller scene;
Added Employee Entity to Core Data model with 2 attributes “name” and “surname”;
Done everything from the answer in How do I bind my Array Controller to my core data model?
Set NSObjectController to entity mode and typed in “Employee”,
Prepares Content selected, Use Lazy Fetching selected so all three options checked;
Binded the NSObjectController’s Managed Object Context in bindings inspector to the View Controller’s managedObjectContext;
Binded NSTextFields as follows: Value - Object Controller, Controller key - selection, Model Key Path - name (for 1st text field) and surname (for 2nd).
That’s it.
First set of questions: What I did wrong and how to fix it if it’s not completely wrong approach?
I’ve read in some post on stackoverflow that doing it that way allows automatic saving and fetching from Core Data model. That’s why I assumed it should work.
So here is a Second set of questions:
Is it true?
If it is then why text fields are not filled when view is displayed?
If it is not then how to achieve it if possible (trying to write as less code as possible)?
Third question: If I used approach that is completely wrong would someone help me to connect Core Data and NSObjectController using Cocoa bindings and show me the way of doing so with as less code written as possible using the right approach?
Taking into account that there no fresh posts about this topic in the wilds I think the right answer could help a lot of people that are developing a macOS app.
Thanks in advance!
I think your basic approach is correct, although it is important to understand that you need a real object, an instance, in order for it to work.
Creating a NSManagedObject subclass is generally desirable, and is almost always done in a real project, so you can define and use properties. You can do it easily nowadays by selecting the data model in Xcode's Project Navigator and clicking in the menu: Editor > Create NSManagedObject Subclass…. Technically it is not necessary, and in a demo or proof-of-concept, you often muddle through with NSManagedObject.
Assuming you are using the Xcode project template as you described, wherein AppDelegate has a property managedObjectContext, the following function in your AppDelegate class will maintain, creating when necessary, and return, what I call a singular object – an object of a particular entity, in this case Employee, which your app requires there to be one and only one of in the store.
#discardableResult func singularEmployee() -> NSManagedObject? {
var singularEmployee: NSManagedObject? = nil
let fetchRequest: NSFetchRequest<NSManagedObject> = NSFetchRequest(entityName: "Employee")
let objects = try? self.managedObjectContext.fetch(fetchRequest)
singularEmployee = objects?.first
if singularEmployee == nil {
singularEmployee = NSEntityDescription.insertNewObject(forEntityName: "Employee", into: self.managedObjectContext)
}
return singularEmployee
}
Then, add this line of code to applicationDidFinishLaunching
singularEmployee()
My web view has several elements, which can be edited by the user to update model objects in the OS X host application.
For some of these elements, when editing delegate methods like webView:shouldChangeSelectedDOMRange:toDOMRange:affinity:stillSelecting: are called, the range arguments are inside a #document-fragment container -without any attribute information at all.
Thus, it is nearly impossible to figure out, what node is being edited - as all id attributes have been stripped.
po proposedRange.commonAncestorContainer.path
/#document-fragment/DIV/DIV/DIV/#text
For other input elements, I get the whole DOM path, with all attribute information intact:
po proposedRange.commonAncestorContainer.path
/#document/HTML/BODY/DIV/DIV/DIV/TABLE/TBODY/TR/TD/DIV/DIV/DIV/DIV/TABLE/TBODY/TR/TD/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/DIV/H1/SPAN/#text
Any ideas what could cause this difference in behavior?
I'm trying to bind an NSTreeController's "arrangedObjects" to a custom view's "managedContent" (so that it can show a custom outline, for instance). In the setter...
- (void)setManagedContent:(NSArray *)newManagedContentArray {
//code goes here
}
nothing ends up working since newManagedContentArray ("arrangedObjects") apparently isn't an NSArray (and therefore I can't addObject: etc. etc.) Instead it's showing up as an NSControllerTreeProxy. My question is, what exactly is "arrangedObjects" supposed to be? Am I supposed to bind to it? If so, how?
arrangedObjects isn't supposed to be an array for NSTreeController. It states this quite clearly in the documentation. What you do get is the proxy object you are seeing, which you can use the childNodes and descendantNodeAtIndexPath: method on to get your tree structure.
When coding with cocoa I've noticed that it's not necessary to have sender parameter when defining IBAction, hence following action:
- (IBAction)showUserInfo:(id)sender;
can be declared as
- (IBAction)showUserInfo;
So I'm wondering if there is any other benefit besides having the button/menu item that sent the action? Only other situation I can think of is having few objects calling same IBAction. Anything else?
Doc says,
The sender parameter usually identifies the control sending the action message (although it can be another object substituted by the actual sender). The idea behind this is similar to a return address on a postcard. The target can query the sender for more information if it needs to.
The sender parameter helps if you want any data from it. For example, on UISegmentControl value change, as in #Mark Adams answer. So if you don't want any information from the sender, you can just omit it, as in your - (IBAction)showUserInfo; example.
It can be handy to use the sender argument when you're connecting the method to UI objects whose values can change and you may need to work with.
For instance if I wired up a method to a UISegmentedControl and set it's control event to UIControlEventValueChanged, I can use the object passed as the sender: argument to obtain it's selected segment index and then, based on the value, make a change in the UI.
-(IBAction)segmentedControlValueChanged:(id)sender
{
UISegmentedControl *control = (UISegmentedControl *)sender;
// Show or hide views depending on the selected index of the segmented control.
if (control.selectedSegmentIndex == 0)
someView.hidden = YES;
else
someView.hidden = NO;
}
In my little cocoa application I have bound the properties of a class to some text fields with help of a NSObjectController. The only problem I have so far: you always have to leave a text field before the NSObjectController updates the class with the current input.
This becomes a problem if the user doesn't leave a texfield and clicks on a Save/Submit Button right away. The class doesn't contain the current input. Always a bad thing.
I am looking for a way to avoid this. Like telling the NSObjectController to get the current input even if the user had exited the field. If this is possible I could put this command in the save-Method before saving and all would be fine.
Send a commitEditing message to your controller in the handler for the OK button. This will do what you're asking for. It's as simple as:
- (void)save:sender {
if (![self.myObjectController commitEditing]) {
// Handle error when object controller can't commit editing
}
// Other stuff
}
If you go to the text field's value binding and check the "Continuously Updates Value" option, that will cause the new value to be set on the model object each time the user changes it, i.e. once for each keystroke. That would ensure that the model had the correct value before closing the window, though it may be a bit overkill, depending on what the effects (if any) are of the value being set in your data model.