I'm developing kind of a plugin for iTunes.
A lot of user have requested, that they would like to start the plugin if they start iTunes, which of course makes sense. However, I'm not sure how to do this.
I thought about a helper app, which is probably the only way.
The only thing that bothers me is how to get the notification.
Of course I could consistently check if iTunes is running, but I'm not sure if that's the right way to do it.
I would rather add my app as an observer of that process.
Is that possible?
If not, how does Activity Monitor do it?
SOLUTION
Thanks to Daij-Djan! I got it working like this:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self
selector:#selector(iTunesLaunched:)
name:NSWorkspaceDidLaunchApplicationNotification
object:nil];
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self
selector:#selector(iTunesTerminated:)
name:NSWorkspaceDidTerminateApplicationNotification
object:nil];
}
-(void) iTunesLaunched:(NSNotification *)notification {
NSRunningApplication *runApp = [[notification userInfo] valueForKey:#"NSWorkspaceApplicationKey"];
if ([runApp.bundleIdentifier isEqualToString:#"com.apple.iTunes"])
NSLog(#"start");
}
-(void) iTunesTerminated:(NSNotification *)notification {
NSRunningApplication *runApp = [[notification userInfo] valueForKey:#"NSWorkspaceApplicationKey"];
if ([runApp.bundleIdentifier isEqualToString:#"com.apple.iTunes"])
NSLog(#"terminate");
}
register for NSWorkspace notifications:
NSWorkspaceDidLaunchApplicationNotification
NSWorkspaceDidTerminateApplicationNotification
see https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSWorkspace_Class/Reference/Reference.html
there is also the possibility to KVO the runningApplications property
btw cocoatech has a nice NTRunningAppManager class that does just that
Related
I have a method in a view controller that sets up some notifications:
- (void)processState
{
MYGame *game = [[MYGameManager sharedInstance] getGameAtIndex:self.indexPath.row];
if(game)
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(notification_gameUpdated:) name:kMYNotificationGameUpdated object:game];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(notification_gameEnded:) name:kMYNotificationGameEnded object:game];
}
}
Then there's a game updated method, which is called every so often:
- (void)notification_gameUpdated:(NSNotification *)notification
{
MYGame *game = notification.object;
_game_status = (game.entity.bet.isWinning) ? MYGameStatusWin : MYGameStatusLose;
}
And finally, when the game ends:
- (void)notification_gameEnded:(NSNotification *)notification
{
MYGame *game = notification.object;
// Clear the notifications
[[NSNotificationCenter defaultCenter] removeObserver:self name:kMYNotificationGameUpdated object:game];
[[NSNotificationCenter defaultCenter] removeObserver:self name:kMYNotificationGameEnded object:game];
self.gameIsActive = NO;
}
Trouble is, that even when I remove the observers (and a breakpoint shows that this is happening), then the notification_gameUpdated: method is still being called. If I change it to
[[NSNotificationCenter defaultCenter] removeObserver:self name:kMYNotificationGameUpdated object:nil];
This still won't clear it. But if I change it to
[[NSNotificationCenter defaultCenter] removeObserver:self name:nil object:game];
Then that does clear it. As does
[[NSNotificationCenter defaultCenter] removeObserver:self];
But I'm not keen on doing either, because I'd rather the code was clean and I don't want any "gotchas" further down the line if I need to add more observers. I've checked the rest of the code and cannot find any other classes adding observers to this object, although other view controllers do listen to the same messages.
Is processState called more than once? That would explain the behavior you are seeing.
If it is, one way to fix the issue would be to always remove listeners before adding them. See e.g. this answer.
edit #2
try registering with object:nil and when you post the notification include the reference to game in the userInfo dictionary. then, in the receiver, you can compare against game and perform whatever action you want if it is a match. this should get you the same behavior as if you were using object:game, although it does not explain why your current implementation isn't working
when you register for notifications like this:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(notification_gameUpdated:)
name:kMYNotificationGameUpdated
object:game];
the #selector will only be performed if that particular instance of game is the sender.
is it possible that you're re-initializing your shared instance of game after registering? that could cause the behavior you're experiencing
try registering for notifications with object:nil and see what happens. (assuming there are not multiple games running concurrently)
So it turned out that the reason for the issue was Method Swizzling. The project I'm working on has addObserver:selector:name:object: and removeObserver:name:object: swizzled. The issue was that although addObserver has been handled correctly, removeObserver is only removing objects on specific conditions. This will obviously need to be changed...
But I post this as a warning to others... Swizzling can be dangerous to your health!
Apologies for any time wasted.
So I need to register a function on OSX (using Xcode / objective C) that will register a particular function to be called whenever the program terminates.
I ran into this but i guess that's for iOS and not for OSX.
I replaced UI with NS and gave it a shot, but it did not work.
NSApplication *app = [NSApplication sharedApplication];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(applicationWillTerminate:)
name:BeCalledOnExit object:app];
but that is not compiling. it says something on name: being an undeclared identifier when it is clearly on the .h & .m file before the function.
i ran into another chap who used this:
-(BOOL) applicationShouldTerminateAfterLastWindowClosed:(NSApplication *) sender{
return TRUE
}
but it doesnt work for me as my app is a complete status bar app.
Basically i'm creating some temp files during my app and just before quitting, i want to make sure that my app is clearing out these files. I am putting it in /tmp/.. Woudn't want too much space to be taken.
i would really like to have a solution like in gcc/python,
atexit(functionName);
Implement - (void)applicationWillTerminate:(NSNotification *)notification on your AppDelegate and it will be called just before the application will terminate
So the Implementation of your AppDelegate could look something like:
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// Insert code here to initialize your application
NSLog(#"I FINISHED LAUNCHING!");
}
- (void)applicationWillTerminate:(NSNotification *)notification
{
NSLog(#"I WILL TERMINATE NOW!!!");
}
#end
Your App Delegate should implement the - (void)applicationWillTerminate:(NSNotification *)notification to get the notification
(OR)
You can implement applicationShouldTerminate and perform clean of your files and return appropriate NSApplicationTerminateReply if your clean up fails
If you want to use a notification, you should be observing NSApplicationWillTerminateNotification.
NSApplication *app = [NSApplication sharedApplication];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(applicationWillTerminate:)
name: NSApplicationWillTerminateNotification object:app];
/*A notification named NSApplicationWillTerminateNotification.*/
- (void)applicationWillTerminate:(NSNotification *)notification
{
}
I created a simple app to learn how to use NSWorkspaceWillSleepNotification and NSWorkspaceDidWakeNotification. My goal is to call a method when the computer sleeps and wakes. The app I created will change each label accordingly. After building the app, I launch it from my desktop. After the application is launched, I put the computer to sleep. When the computer wakes the labels in the application do not change. I added IBAction buttons to the window to make sure that the labels would change. When buttons are pressed the labels do indeed change. But I want something like this to happen automatically upon sleep and wake. What am I doing wrong?
#import "Controller.h"
#implementation Controller
- (void)fileNotifications {
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver: self
selector: #selector(makeSleep:)
name: NSWorkspaceWillSleepNotification
object: nil];
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver: self
selector: #selector(makeWake:)
name: NSWorkspaceDidWakeNotification
object: nil];
}
- (IBAction)makeSleep:(id)sender {
[sleepLabel setStringValue:#"Computer Slept!"];
}
- (IBAction)makeWake:(id)sender {
[wakeLabel setStringValue:#"Computer Woke!"];
}
#end
Instead of [[NSWorkspace sharedWorkspace] notificationCenter] try using [NSNotificationCenter defaultCenter]
like this:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(makeSleep:)
NSWorkspaceWillSleepNotification
object:nil
];
and
[[NSNotificationCenter defaultCenter] addObserver:self
#selector(makeWake:)
NSWorkspaceDidWakeNotification
object:nil
];
The above is incorrect, see https://developer.apple.com/library/mac/qa/qa1340/_index.html
Using [[NSWorkspace sharedWorkspace] notificationCenter] is necessary.
You should add observers upon - (void)awakeFromNib method.
For example, get the notification that another Application is becoming Active on the screen, or resign active state.
Sure. In your app delegate class, you can use NSWorkspace to get notified when an app becomes active (NSWorkspaceDidActivateApplicationNotification) or resigns active (NSWorkspaceDidDeactivateApplicationNotification). See the documentation on NSWorkspace for more info.
In your controller class, you'd do something like this:
- (id)init {
if ((self = [super init])) {
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self
selector:#selector(appDidActivate:)
name:NSWorkspaceDidActivateApplicationNotification
object:nil];
}
return self;
}
- (void)dealloc {
[[[NSWorkspace sharedWorkspace] notificationCenter] removeObserver:self];
[super dealloc];
}
- (void)appDidActivate:(NSNotification *)notification {
NSDictionary *userInfo = [notification userInfo];
NSLog(#"userInfo == %#", userInfo);
}
The key points are basically that you need to register to receive the notifications like shown in -init. You'd repeat the code to add another observer for each additional notification name that you want (e.g NSWorkspaceDidDeactivateApplicationNotification).
Another important thing to remember is to remove yourself as an observer in -dealloc (or elsewhere), so that NSWorkspace doesn't try to notify your controller object after it's been released+dealloc'd (and would no longer be valid).
In the specified -appDidActivate: method, do whatever you need to with the info about the app in question.
If you want something simpler than distributed objects, you could use distributed notifications from the distributed notification center. However, these are not posted unless you built the application. For monitoring when applications start or quit, you can use NSWorkspace and its notification center (suggested by NSGod)
So I'm new to NSNotifications, I am wondering what the scope is. I.e. If I have an Application Delegate Class, and it is the receiver of a notification:
-(id)init
{
[ super init];
if (!self) return nil;
// Add to our notification
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(receiveUpdateRequest:)
name:#"RequestStatusUpdate"
object:nil];
return self;
}
And has this method run on receive:
- (void) receiveUpdateRequest:(NSNotification *) notification
{
// Check the Notification Name
if ([[notification name] isEqualToString:#"RequestStatusUpdate"]){
NSLog (#"Recieved Update Status!");
}
else {
NSLog(#"Recieved Notification: %#",[notification name]);
}
}
Can I post a notification like so:
[[NSNotificationCenter defaultCenter] postNotificationName:#"RequestStatusUpdate" object:self];
From another object instance any where in my App?
Even for instance an object that instantiated by virtue of a NIB being loaded:
summaryWindow = [[SummaryWindowController alloc] initWithWindowNibName:#"SummaryWindow" owner:globalStatusController];
Do I have to have anything else configured in my summaryWindow Class to be able to call the postNotificationName method.
Or put a different way is the [NSNotificationCenter defaultCenter] global for all instances of all objects in my Application, I would assume thats how its suppose to work but currently when I call this method via an IBAction in my SummaryWindow , the notification does not seemed to be received.
I have tested both [NSThread currentThread] and the default Notification center and it does look like I'm in the thread and the same notification center ( which I think is always global). I am only looking into the thread thing as its come up on a few other threads.
2011-08-22 20:57:11.452 AppName[23102:1307] Using Default Notification Center: <CFNotificationCenter 0x10012c900 [0x7fff7d302ea0]>
2011-08-22 20:57:20.366 AppName[23102:1307] Using Default Notification Center: <CFNotificationCenter 0x10012c900 [0x7fff7d302ea0]>
Wow that was lame, I just found [[NSNotificationCenter defaultCenter] removeObserver:self]; in some earlier code. I had it in dealloc but some how managed to miss it in another NSTask method I was working on.
Or put a different way is the [NSNotificationCenter defaultCenter] global for all instances of all objects in my Application
Yes.
I would assume thats how its suppose to work but currently when I call this method via an IBAction in my SummaryWindow , the notification does not seemed to be received.
That's because you're registering in init. I'm betting this is Mac, and on Mac the application delegate is almost always instantiated from a nib file. You need to do this work in awakeFromNib.
Note that you generally do not need to check the notification's name. It's generally best to have a different method for each notification callback. You should also always create a string constant for your notification names. It's way too easy to mis-type them.