So I'm trying to do this exercise where I need to set a delegate for the main window. The purpose is to make sure that when the user resizes the window, it's always twice as wide as it is high.
This is my AppController.h file:
#import <Cocoa/Cocoa.h>
#interface AppController : NSObject
{
NSWindow *windowWillResize;
}
#end
and this is my AppController.m file:
#import "AppController.h"
#implementation AppController
- (id) init
{
[super init];
windowWillResize = [[NSWindow alloc] init];
[windowWillResize setDelegate:self];
return self;
}
- (NSSize) windowWillResize:(NSWindow *)sender
toSize:(NSSize)frameSize;
{
NSLog(#"size is changing");
return frameSize;
}
#end
However, I can remove the line
[windowWillResize setDelegate:self];
since I set the delegate in Interface Builder, but I'm not sure why this works.
How does windowWillResize know that I'm referring to the main application window since I'm doing a completely new
windowWillResize = [[NSWindow alloc] init];
I have a feeling that I am completely doing this wrong. Could someone point me in the right direction? Thanks!
Indeed, you don't need to create a NSWindow *windowWilResize since a newly created Cocoa app already has a main window. You don't need to implement an -init method either.
You only need to set you appController as a delegate of your main window in Interface Builder and to implement the -windowWillResize: method in your appController.
If you are familiar with french language, you can take a look at a blog entry I have written on this subject: Délégation en Cocoa.
You're leaking an instance of NSWindow. In -init you create an NSWindow instance. However, that is not used because when the NIB loads, it sets up all the connections that you specified in Interface Builder and you start using the window from the NIB instead. Do not create a window object in code - Interface Builder does it for you! :-)
In fact, it's not quite "instead"; your app controller is now the delegate for both NSWindow instances - the one that comes from the NIB and the one you instantiated in -init. However as the in-code NSWindow is never used anywhere else, it's still redundant and should be removed.
If you just want to maintain the aspect ratio of the window you can use either of these two NSWindow methods:
setAspectRatio:(NSSize)
setContentAspectRatio:(NSSize)
The first method locks the entire window size, including the title bar. The second one just the content. You can call this method during the initialization of your window inside the delegate (for example: -applicationDidFinishLaunching)
Related
I'm going through this book called "cocoa programming for mac os x" and I just started with delegates. This whole thing with delegates is still a little bit wacky to me but I think I just need to let it settle.
However there was this one exercise where I should implement a delegate of the main window so that if resized height is always 2xwidth.
So I got 4 files:
AppDelegate.h
AppDelegate.m
WindowDelegate.h
WindowDelegate.m
AppDelegate are just the two standard files that get created when you open a new Cocoa project. I had to look up the solution because I didn't quite know how to accomplish this task.
The solution was just to create a new cocoa class, "WindowDelegat.h/.m" and add this to it's implementation file:
- (NSSize)windowWillResize:(NSWindow *)sender toSize:(NSSize)frameSize {
NSSize newSize = frameSize;
newSize.height = newSize.width * 2;
return newSize;
}
Then I opened the interface builder, added a new object and made it my WindowDelegate. I then had to ctrl drag from the WindowDelegate to the actual window and made it the window's delegate.
Clicked run and it worked. Yay! But why?
First I thought that "windowWillResize" is just one of these callback functions that get's called as soon as the window is resized but it isn't. Normally methods get invoked because the general lifecycle of an program invokes them or because they are an #IBAction, a button or different control elements.
But "windowWillResize" is non of them. So why is it called?
EDIT: Problem solved! Thanks a lot!
Now I'm trying to connect the delegate to the window programmatically. Therefore I deleted the referencing outlet from WindowDelegate to the actual window in interface builder. It works but I just want to verify that this it the correct way how it's done:
AppDelegate.h
#import <Cocoa/Cocoa.h>
#import "WindowDelegate.h"
#interface AppDelegate : NSObject <NSApplicationDelegate>
#end
AppDelegate.m
#import "AppDelegate.h"
#interface AppDelegate ()
#property (weak) IBOutlet NSWindow *window;
#property (strong) WindowDelegate *winDeleg;
#end
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
// Insert code here to initialize your application
}
- (void)applicationWillTerminate:(NSNotification *)aNotification {
// Insert code here to tear down your application
}
- (void)awakeFromNib {
[_window setOpaque:NO];
NSColor *transparentColor = [NSColor colorWithDeviceRed:0.0 green:0.0 blue:0.0 alpha:0.5];
[_window setBackgroundColor:transparentColor];
NSSize initialSize = NSMakeSize(100, 200);
[_window setContentSize:initialSize];
_winDeleg = [[WindowDelegate alloc] init];
[_window setDelegate: _winDeleg];
}
#end
WindowDelegate.h
#import <Foundation/Foundation.h>
#import <Cocoa/Cocoa.h>
#interface WindowDelegate : NSObject <NSWindowDelegate>
#end
WindowDelegate.m
#import "WindowDelegate.h"
#implementation WindowDelegate
- (NSSize)windowWillResize:(NSWindow *)sender toSize:(NSSize)frameSize {
NSSize newSize = frameSize;
newSize.height = newSize.width * 2;
return newSize;
}
- (id)init {
self = [super init];
return self;
}
#end
Why does the #property of WindowDelegate need to be strong?
And isn't my winDeleg an object? Why do I have to access it through _winDeleg when it's an object. I though the underscore is used to access variables?
Thank you for your help!
Clicked run and it worked. Yay! But why?
Because instances of NSWindow have a delegate property that can point to any object that implements the NSWindowDelegate protocol, and that protocol includes the -windowWillResize:toSize: method.
Read that a few times. The reason it's important is that you can create your own object, say that it implements NSWindowDelegate, implement -windowWillResize:toSize:, and set that object as your window's delegate. Then, whenever the user resizes the window, your method will be called and can modify the proposed new size.
Normally methods get invoked because the general lifecycle of an program invokes them or because they are an #IBAction, a button or different control elements. But "windowWillResize" is non of them. So why is it called?
This really isn't so different. Think of delegates as "helper objects." They let you customize the behavior of an object without having to create a whole new subclass. The NSWindowDelegate object is essentially a contract that the NSWindow promises to follow: whenever certain things happen, such as the user resizing the window, the window will call certain methods in its delegate object, if the delegate exists and implements those methods. In the case of NSApplication, a lot of those delegate methods are application lifecycle events, like the app starting up or quitting or getting a message from the operating system. In the case of NSWindow, delegate methods correspond to interesting events that can happen to a window, like the user moving it, hiding it, showing it, maximizing it, moving it to a different screen, etc. Other classes, like text views or network connections or movie players, have their own sets of interesting events and their own delegate protocols to match.
Note that methods marked IBAction really aren't delegate methods, they're just methods that get called by objects like controls that use a target/action paradigm. The IBAction keyword lets the IDE know which methods it should present as possible actions for things like buttons. You often find actions in window controllers and view controllers, and those objects frequently act as a delegate for some other object, but the actions themselves aren't part of the delegate protocol. For example, NSTableView takes a delegate object that determines how the table will act and what's displayed in it. It often makes sense for the view controller that manages the table to be the table's delegate, and that same view controller might also manage some buttons and contain the action methods that said buttons trigger, but the actions aren't part of the NSTableViewDelegate protocol and you therefore wouldn't call them delegate methods.
Simple structure:
exampleController.h :
#import <Foundation/Foundation.h>
#interface exampleController : NSWindowController {
#public
IBOutlet NSPanel *entryPanel;
#property (nonatomic, strong) IBOutlet NSPanel *entryPanel;
#end
exampleController.m :
#import "exampleController.h"
#implementation exampleController
#synthesize entryPanel;
- (id)init {
self = [super initWithWindowNibName:#"ExamplePanel"];
if (self) {
// Initialization code here.
NSLog(#"entryPanel: %#", entryPanel);
[self.entryPanel setTitle:#"TESTING!"];
}
return self;
}
randomController.m :
...
- (id) init {
self = [super init];
if (self) {
// loading our example controller if it isn't loaded yet.
if (!ourExampleController) {
ourExampleController = [exampleController alloc] init];
}
}
return self;
}
...and then later in the random controller within a method I show the NSPanel via:
[ourExampleController showWindow:self];
[ourExampleController window] makeKeyAndOrderFront:self];
My problem is that no matter what, the first time the NSPanel displays and shows itself the title is always still set to the title that it has in Interface Builder! Even though I explicitly set the title in the exampleController init method.
I've also tried throwing an NSLog(#"entryPanel: %#", entryPanel) in the init method for exampleController and at launch it is always NULL. I do not have to ALLOC all my IBOutlets in the init because I am already synthesizing them?
I've double checked everything in interface builder. The File Owner for the ExamplePanel.xib is set to the exampleController class. The window AND entryPanel outlets are both referencing the NSPanel in our xib file. What am I missing ??
Thanks in advance!
EDIT: Just to add. If I open the window (..and see the default IB title) and then close it and reopen it with a method that changes the title - it seems to work! This problem seems to only reside with the window first opening. It seems like my properties are not being alloc'd until the window first opens?
EUREKA!
As per discussion here:
IBOutlet instances are (null) after loading from NIB
I learnt that the window itself is not loaded when my controller is initialized. Found that surprising since I figured using initWithWindowNibName:#"myNibFile" would also alloc and initialize all outlet properties but since I'm new to OSX Obj-C that appears to not be the case. All the outlet properties are only alloc'd once the window itself is loaded too.
It's easy to just show the window (which also loads the window if it's not loaded yet) and then quickly set all the outlets to my desired values BUT this was an issue for me since I wanted to avoid that ever so slight "screen flicker" (for lack of a better description) that occurs as the values adjust to their new settings.
The solution was to find a way to load the controller and load the window without actually showing it first! Then I discovered this:
Can you force a NSWindow to load, i.e. before it is presented onscreen?
Steps to make that happen:
Add the following to my NSWindowController subclass init method:
// this loads the window as per link/description above
[self window]
The key seems to be though to ensure that in your NIB/XIB file that the Visible At Launch is unchecked. If it is checked (default behavior) then the [self window] call above will still show your window when your app launches. Unchecking the above option ensures the above call does not show your window until you explicitly show it yourself!
E.g. You can define an action button which loads your window:
[exampleController showWindow:self];
[[exampleController window] makeKeyAndOrderFront:self];
Hope this helps someone else out. Was a head scratcher for a couple hours!
You should set the title, etc. in -awakeFromNib or -windowDidLoad instead of an -init… method. That way the values will be set before the window is shown and you won't get the flicker.
In this answer is said it is possible to have a custom NSWindowController by removing the window from MainMenu.xib and instantiating the window controller 'manually' from applicationDidFinishLaunching:. But it also says:
To stop the default window from showing I just delete it. There's probably a better way but I don't know that.
Is there a better way? What is that better way, should it exist? Is it considered 'normal' practice to get your own window controller?
To do this, you would usually subclass NSWindowController and change the File's Owner class to your WindowController subclass in the nib.
EDIT:
If you aren't doing a document-based app, and just want an NSWindowController of your own to do on-demand loading of Nibs (completely reasonable), then you'd delete the window from your nib and instantiate an NSWindowController subclass programmatically, using it explicitly to do your window loading...
#implementation MyApplicationDelegate {
MyWindowControllerSubclass *windowController;
}
-(void)applicationDidFinishLaunching:(NSNotification *)notification {
windowController = [[MyWindowControllerSubclass alloc] initWithWindowNibName:#"MyWindowNib"];
[windowController showWindow:nil];
[windowController.window makeKeyAndOrderFront:nil];
}
I was running into the same issue and I want to show you my own solution.
Create a normal Cocoa Application (not Document Based)
Go to MainMenu.xib an delete the Window
Go ahead and create a new file, User Interface -> Window
After that create a subclass of NSWindowController
Open the just created xib file and set the Custom Class in the Identity inspector to the just created subclass of NSWindowController
Right click on File's Owner and connect the window property to the actual window
Now go to the AppDelegate an create an instance variable that holds you CustomWindowController
Last thing you have to do is instantiate your CustomWindowController self.customWindowController = [[AccountWindowController alloc] initWithWindowNibName:#"CustomWindow"]; and show the Window [self.customWindowController showWindow:nil] in - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
Here is an example project https://www.dropbox.com/s/ft3t7w72806tnoe/CustomWindowController.zip
I actually found another way: NSWindowController has the method -initWithWindow:. Because the App Delegate has a property window which is linked to the window from MainMenu.xib on startup, it was easy to link it to my WindowController:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
MyWindowController *wincon = [[MyWindowController alloc] initWithWindow:window];
}
I have yet to research this, but I don't get any errors.
I'm learning some obj-c and therefore i'm building a small cocoa application.
From the MainMenu.xib i have added a menu to the "Main menu" in the top. When click, this triggers a IBAction that opens an instance of a window, in this case a window for managing categories.
This category window has a NSWindowController, looks like this:
// CategoriesWindow.h
#import <Cocoa/Cocoa.h>
#interface CategoriesWindow : NSWindowController
-(IBAction)OpenCategoriesWindow:(id)sender;
#end
// CategoriesWindow.m
#import "CategoriesWindow.h"
#implementation CategoriesWindow
-(IBAction)OpenCategoriesWindow:(id)sender
{
CategoriesWindow *Categories = [[CategoriesWindow alloc] initWithWindowNibName:#"CategoriesWindow"];
[Categories showWindow:self];
}
#end
To this i have a CategoriesWindow.xib with a NSTableView that does some things, so there for i have a CategoryTableController.h and .m that handles the data for this table.
When i hit a button i want it to do a bunch of things, and then i want the window to close it self. That is, i want this window to close itself from a IBAction in the CategoryTableController.m.
How do I do this? One bad thing with this setup (followed from a tutorial somewhere...) is that I can open a lots of instances of this window by clicking the menu-button.
Any tips or ideas where to begin?
From there Reference:
[Categories close];
However there is something wrong with your implementation as you are creating an instance of the class from an instance method of the class. That doesn't look right to me. Also you aren't retaining the new instance anywhere, so it will be possibly destroyed under ARC or leaked under MRR.
I think you might want:
-(IBAction)OpenCategoriesWindow:(id)sender
{
[self showWindow:sender];
}
-(IBAction)CloseCategoriesWindow:(id)sender
{
[self close];
}
Although I can't be sure.
I am creating some sample applications to understand the concepts of view navigation, binding etc in cocoa.
Here is the scenario:
I have a window that has a tab view(2 tabs) in MainMenu.Xib.
I have a text field in the first tab and label in the second tab. I want both of them to reflect the same value and I want to do this using binding. Also, I don't want to use the views provided to me along with the tab view.
These are the steps I have done.
The view of each tab view item is set separately in the applicationDidFinishLaunching: method using the following code:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// Insert code here to initialize your application
//initialize view controllers
view1=[[ViewTab1 alloc] initWithNibName:#"ViewTab1" bundle:nil];
view2=[[ViewTab2 alloc] initWithNibName:#"ViewTab2" bundle:nil];
//set views
[[[myTabView tabViewItems] objectAtIndex:0]setView:view1.view];
[[[myTabView tabViewItems] objectAtIndex:1]setView:view2.view];
}
myTabView is the outlet reference of the tab view from MainMenu.xib in AppDelegate.
ViewTab1 is the name of the first view controller (and the xib).
ViewTab2 is the name of the second view controller (and the xib).
ViewTab1 has one single text field (and an associated label). I have bound this to a variable(name) declared in AppDelegate.
ViewTab2 has a label. I have bound this also to the same variable in AppDelegate.
The variable, 'name' is initialized in the init method of AppDelegate.
AppDelegate.h
....
NSString *name;
....
#property(strong) ViewTab1 *view1;
#property(strong) ViewTab2 *view2;
#property (assign) IBOutlet NSTabView *myTabView;
#property (strong) NSString *name;
....
AppDelegate.m
....
#synthesize myTabView;
#synthesize view1,view2;
#synthesize name;
....
- (id)init {
self = [super init];
if (self) {
name=#"dummy";
}
return self;
....
Apart from this I haven't done any coding in my program.
In the ViewTab1.xib I got an object and made it an instance of AppDelegate and then connected the delegate reference of the Application object(NSApplication) to the same object. (I hope this is the right way of getting the AppDelegate object.)
I did the same in ViewTab2.xib
Then I bound the text field in ViewTab1 and label in ViewTab2 to this variable in AppDelegate.
When I run the program both the text field and label shows "dummy". But when I change the value in the text field, its not reflected in the label in the second tab( i.e. ViewTab2).
Please tell me what I'm doing wrong.
How to establish binding to the same App delegate object from any loaded Nib?
Yes, I know this frustrated situation as described in question... after many weeks and hundreds pages of documentation for KVO - Notifications - Bindings I think there is one very simple solution for that.
As we can find in some information sources the nib-loading process produce new instances of members... and we need to use binding connection to the old one.
Note that bindings made in InterfaceBuilder are redirect to these new instances automatically after loading nib
Why not redirect the pointer of App delegate to the old instance?
In method where you loads your nib you can test which object is app delegate before and just after nib load.
If the new one isn’t the same as the previous one you can redirect it as you want.
This simple example works for me in Xcode3 under 10.5.8 with target to OSX10.5 / i386:
// ***** SOMEWHERE IN DEFAULT APP-DELEGATE.m IMPLEMENTATION
- (IBAction) createOtherWindowFromNib: (id)sender
{
// ensure that app delegate is set as you want...
[NSApp setDelegate:self];
NSLog(#"APP-DELEGAT **** CREATE-TEST-WINDOW ***** WHO IS APP-DELEGATE BEFORE NIB LOAD: %# ", [[NSApp delegate] description]);
// we can bind members of the nib to this controller over proxy object named "File’s Owner"
NSWindowController *otherWinCapo = [[NSWindowController alloc] initWithWindowNibName: #"OtherTestWindow"];
NSLog(#"APP-DELEGAT **** CREATE-TEST-WINDOW ***** WHO IS APP-DELEGATE AFTER NIB LOAD: %# ", [[NSApp delegate] description]);
// make some test for delegates before/after here if you need ...
// usually your bindings made inside "OtherTestWindow.xib" by IB doesn’t works in this moment
// ... and some redirection if needed
[NSApp setDelegate:self];
// afer that the bind made in IB inside "OtherTestWindow.xib"
// referred to (proxy object) "Application.delegate.myBOOL" (Bind to:Application, Model Key Path:delegate.myBOOL)
// react to changes of myBOOL placed in default app delegate object as expected
// simultaneously in every open instance of "OtherTestWindow.xib"
[otherWinCapo showWindow: otherWinCapo.window]; // we need populate the window instance on screen to see it
}
I think the problem is that the objects in your xibs that you set to the app delegate class create 2 different instances of the app delegate, so changing the value of the text field changes the value of name in one instance but not in the other. That's what you're doing wrong, unfortunately, I can't think of a solution at this time.
Have you turned on 'Continuously Updates Value' in the NSTextField controls?
See this example.