I have several panels that contain NSTextField controls bound to properties within the File's Owner object. If the user edits a field and then presses Tab, to move to the next field, it works as expected. However if the user doesn't press Tab and just presses the OK button, the new value is not set in the File's Owner object.
In order to workaround this I have set Updates Continuously in the binding, but this must be expensive (EDIT: or at least it's inelegant).
Is there a way to force the bind update when the OK button is pressed rather than using Updates Continuously?
You're right that you don't need to use the continuously updates value option.
If you're using bindings (which you are), then what you should be doing is calling the -commitEditing method of the NSController subclass that's managing the binding. You'd normally do this in your method that closes the sheet that you're displaying.
-commitEditing tells the controller to finish editing in the active control and commit the current edits to the bound object.
It's a good idea to call this whenever you are performing a persistence operation such as a save.
The solution to this is to 'end editing' in the action method that gets called by the OK button. As the pane is a subclass of NSWindowController, the NSWindow is easily accessible, however in your code you might have to get the NSWindow via a control you have bound to the controller; for example NSWindow *window = [_someControl window].
Below is the implementation of my okPressed action method.
In summary I believe this is a better solution to setting Updated Continuously in the bound controls.
- (IBAction)okPressed:(id)sender
{
NSWindow *window = [self window];
BOOL editingEnded = [window makeFirstResponder:window];
if (!editingEnded)
{
logwrn(#"Unable to end editing");
return;
}
if (_delegateRespondsToEditComplete)
{
[_delegate detailsEditComplete:&_mydetails];
}
}
Although this is really old, I absolutely disagree with the assumption that this question is based on.
Countinously updating the binding is absolutely not expensive. I guess you might think this updates the value continuously, understanding as "regularly based on some interval".
But this is not true. This just means it updates whenever you change the bound value. This means, when you type something in a textView, it would update as you write; this is what you'd want in this situation.
Related
I am using MonoMac to build a desktop download manager for Mac in C#.
My XIB has a Table View, whose columns are bound to an NSArrayController. The array controller is connected to my Main Window Controller through an IBOutlet. The array holds a bunch of HttpDownload objects, which derive from NSObject. These HttpDownload objects contain properties such as TotalSize, TotalDownloaded, Bandwidth, etc. I have decorated these properties with an [Export] attribute.
In the controller I add some HttpDownload objects to the NSArrayController using the AddObject method. A background process, started with Task.Factory.StartNew() begins the download asynchronously and updates the bound properties such as TotalDownloaded and Bandwidth as data is received.
I can see these new values being reflected in the Table View, but only once I've "forced" a UI update, for instance by causing the window to lose focus, gain focus, or by clicking on a button within the window.
I have tried setting Continuously Updates Value in IB, but this makes no difference (and reading the docs, I didn't think it should).
Does anyone know to make the UI update the bound values in "real time", instead of only when a window event occurs?
I figured this out shortly after I posted this question.
It seems that we need to manually call WillChangeValue() and DidChangeValue() for at least one of the keys that are being updated, for instance, when I updated the total downloaded:
WillChangeValue("DownloadedBytes");
DownloadedBytes += bytesRead;
DidChangeValue("DownloadedBytes");
In my case, calling these methods for just one of the updated keys seems to be enough to force an update of all the bound values.
For reference, in Objective-C these selectors are called [self willChangeValueForKey:#"keyname"] and [self didChangeValueForKey:#"keyname"].
I have a Core Data project.
Basically I have an NSTableView where I add some entities (using the "add:" selector), double clicking on the TableView opens a new NSWindow where is possible to edit the entity using some NSTextFields.
Each text field is binded to an attribute of the entity.
Everything is working fine, except the fact that the entity's attributes are updated only when a textfield lose the focus.
If I write on the first text field and then I move to the second one my entry is saved, but if I write on the first text field and I close the window I lose my changes.
How can I update my core data entity as soon as I write something in the text field? Should I use textDidChange:?
--- UPDATE ---
Unfortunately [context save] doesn't work. If I understand correctly the entity is not modified until the NSTextField resign first responder.
The only working solution for now is something like:
(void)controlTextDidChange:(NSNotification *)aNotification
{
NSTextField *tf = [aNotification object];
[self.window makeFirstResponder:tf];
}
but this is quite inelegant, and in any case I also still need to re-set the cursor at the end of the NSTextField.
Setting NSContinuouslyUpdatesValueBindingOption will cause the model to update every time the text field changes, which sets the dirty flag properly and causes the document to save on quit.
I think you could use DidEndEditing or TextDidChange, another way of doing this is handeling in the window close event, but I would not recommend it.
If you don't have one already, you can set a delegate on the window and use -windowWillClose: or observe the NSWindowWillCloseNotification. You can then call [[notification object] makeFirstResponder:[window initialFirstResponder]] to set the window's first responder to its initial first responder as the window is closing. This will cause the control that is first responder (e.g. NSTextField) to resign the first responder status and the binding will save the changes.
I'm a complete n00b with MacRuby and Cocoa, so keep that in mind when answering - I need lots of details and explanation. :)
I've set up a simple project that has 2 windows in it, both of which are built with Interface Builder. The first window is a simple list of accounts using a table view. It has a "+" button below the table. When I click the + button, I want to show an "Add New Account" window.
I also have an AccountsController < NSWindowController and a AddNewAccountController < NSWindowController class, set up as the delegates for these windows, with the appropriate button click methods wired up, and outlets to reference the needed windows.
When I click the "+" button in the Accounts window, I have this code fire:
#add_account.center
#add_account.display
#add_account.makeKeyAndOrderFront(nil)
#add_account.orderFrontRegardless
this works great the first time I click the + button. Everything shows up, I'm able to enter my data and have it bind to my model. however, when I close the add new account form, things start going bad.
if I set the add new account window to release on close, then the second time I click the + button, the window will still pop up but it's frozen. i can't click any buttons, enter any data, or even close the form. i assume this is because the form's code has been released, so there is no message loop processing the form... but i'm not entirely sure about this.
if i set the add new account window to not release on close, then the second time i click the + button, the window shows up fine and it is usable - but it still has all the data that i had previously entered... it's still bound to my previous Account class instance.
what am I doing wrong? what's the correct way to create a new instance of the Add New Account form, create a new Account model, bind that model to the form and show the form, when I click the + button on the Accounts form?
... this is all being done on OSX 10.6.6, 64bit, with XCode 3.2.4
The issue is that it doesn't create the window each time. Release on close is a bit of an annoying option and generally is only used if you know the window controller is also being released when the window closes. (Note I've never used MacRuby so I'll be giving code in Obj-C as I know that it is correct, hopefully you can convert it. I'll be assuming GC is on as it should be with MacRuby).
Now there are two ways to do this. I'm not entirely sure how your NIB/classes are set up as it could be one of two ways.
--
The first way to solve it is to use the outlets you use to reference the form elements to blank them out when you display the window again eg [myTextField setStringValue:#""]. If you're using cocoa bindings then it's a little trickier, but basically you have to make sure the bound object is blanked out. I would recommend against bindings though if you are new to Cocoa.
--
The second way is to make the AddNewAccountController class a subclass of NSWindowController. When you press the + button you would then create a new instance of it and display it (remember to store it in an ivar). The best way to do it would be as so:
if (!addAccountController) {
addAccountController = [[AddNewAccountController alloc] initWithWindowNibName:#"AddNewAccountController"];
[[addAccountController window] setDelegate:self];
}
[addAccountController showWindow:self];
This prevents a new instance being made if the window is already visible. You then need to implement the delegate:
- (void)windowWillClose:(NSNotification *)notification {
//If you don't create the account in the AddNewAccountController then do it here
addAccountController = nil;
}
Obviously you would need to move the window to a separate NIB called "AddNewAccountController". In this NIB make sure to set the class of the File's Owner to AddNewAccountController and then to connect the File's Owner's window outlet to the window.
When all this is set up, you will get a fresh controller/window each time. It also has the benefit of splitting up nibs and controllers into more focused units.
--
One last thing. While it is fine to do something like this in a window, you may want to eventually look at doing this via a sheet, as it would then prevent the possibility of the add account window getting hidden behind other windows.
For most actions, I just click and drag in InterfaceBuilder to "wire up" a call from some interface object to my code. For example, if I want to know when the user single-clicks a row in a table, I drag a connection from the table's action to my controller's action.
But now let's consider the user double-clicking a row. If I want one of my actions to be called when this happens, I need to call not only -[NSTableView setDoubleAction] but also -[NSControl setTarget]. Why?
To be clear, I am not asking why Interface Builder doesn't support setDoubleAction. All tools have limitations. I am trying to gain a greater understanding about how and why setTarget doesn't seem to be necessary unless and until I want setDoubleAction to work. Another way to ask this question would be: Why don't I need to do anything in Interface Builder to set the target of the table's (single-click) action?
If you connect your table view to an action in IB, then call setDoubleAction on it, there should be no need to make an additional call to setTarget. However, if you only wish to receive the double click message, and you didn’t connect the table view to an action in IB, you will have to call setTarget.
A table view will send action and doubleAction to the same target. You can imagine NSTableView as being implemented like this:
#implementation NSTableView
- (void)theUserClickedOnMe
{
[self sendAction:[self action] to:[self target];
}
- (void)theUserDoubleClickedOnMe
{
[self sendAction:[self doubleAction] to:[self target]];
}
#end
And what you’re doing in IB is something like this:
- (void)userConnectedControl:(NSControl *)control
toAction:(SEL)action
ofObject:(id)object
{
[control setTarget:object];
[control setAction:action];
}
The real implementations are nowhere close to that, but that is effectively what’s going on.
If you set an action (or double-click action) and don't set a target (or set the target to nil), then the action message will go through the responder chain.
If you set a target in addition to an action, the action message will go only to that object.
I am building a Cocoa desktop application. I want to know when a NSView's isHidden status has changed. So far using target/action doesn't help, and I can't find anything in NSNotification for this task. I would like to avoid overriding the setHidden method, because then I'll have to override all the NSView derived class that I am using.
UPDATE: I ended up using KVO. The path for "isHidden" is "hidden", probably because the setter is "setHidden".
You could use Key-Value Observing to observe the isHidden property of the NSView(s). When you receive a change notification from one of these views, you can check if it or one of its superviews is hidden with -isHiddenOrHasHiddenAncestor.
A word of warning: getting Key-Value Observing right is slightly tricky. I would highly recommend reading this post by Michael Ash, or using the -[NSObject gtm_addObserver:forKeyPath:selector:userInfo:options] method from the NSObject+KeyValueObserving category from the Google Toolbox for Mac.
More generally, one can override viewWillMoveToWindow: or the other related methods in NSView to tell when a view will actually be showing (i.e. it's window is in the window display list AND the view is not hidden). Thus the dependency on KVO for the 'hidden' key used above is removed, which only works if setIsHidden has been called on that view. In the override, 'window' (or [self window]) will indicate whether the view is being put into a visible view hierarchy (window is non-nil) or being taken out of it (window is nil).
I use it for example to start/stop a timer to update a control from online data periodically - when I only want to update while the control is visible.
Could you override the setter method for the hidden property so that it will trigger some custom notification within your application?