Coming from a .NET background I'm used to events getting fired so trapping a lost focus event is easy but I'm not sure how to do this in Obj-C. Basically I want my app to know when another application has gotten focus and it no longer has it so it can perform some actions.
Can you please tell me how I can implement this kind of functionality in Obj-C for an OSX app?
Have a look at the NSWindow notifications. Specifically, you're interested in NSWindowDidBecomeKeyNotification and NSWindowDidResignKeyNotification. You can also create a delegate for the window and implement its windowDidBecomeKey: and windowDidResignKey: methods, as noted in the NSWindowDelegate protocol documentation.
Or, if you just wanted to know when the application (not a window) has gained focus, you can subscribe to the NSApplicationDidBecomeActiveNotification. Likewise, NSApplicationDidResignActiveNotification will notify you when your app loses focus. These notifications are discussed more here. You can also implement applicationWillBecomeActive: and applicationWillResignActive: in the application delegate.
It's unclear if you want notification of a single window losing focus or notification of your entire app losing focus. My answer here provides notification for the entire application losing focus. (See mipadi's answer if you just want to know when one of your app's window loses focus.)
Observe the appropriate notification:
[[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self
selector:#selector(appDeactivated:)
name:NSWorkspaceDidDeactivateApplicationNotification
object:nil];
Then add the handler method:
-(void) appDeactivated:(NSNotification *)notification
{
NSRunningApplication* app = [notification.userInfo objectForKey:#"NSWorkspaceApplicationKey"];
if (app == [NSRunningApplication currentApplication]) {
// your cleanup code here
}
}
Related
For a Mac application, I want to detect user activity in the app, so I can periodically let a web service know that the user is still active on the endpoint.
In Cocoa Touch, I would override sendEvent of UIApplication, but the sendEvent in NSApplication equivalent in Cocoa, doesn't do the same.
Which APIs should I use instead for a Mac application, to detect user activity? Can I perhaps somehow have a global responder hookup from where I can send the pings to my service?
Preferably, I want to listen for actions the user can be expected to perform every 15-30 second, ie. clicks, tabs, typing, switching windows or applications.
You most likely want to create a global event monitor using +[NSEvent addGlobalMonitorForEventsMatchingMask:handler:]. This calls your handler whenever an event whose type matches the passed mask (you should use NSAnyEventMask) is sent to another application. You can observe, but not change, the event here, which suits your usage perfectly. There is one thing to watch out for: the documentation says that you won't receive key events unless your app is trusted for Accessibility.
You can do similarly for events that are routed to your own application with +[NSEvent addLocalMonitorForEventsMatchingMask:handler:].
It's not a notification, but you can query the time since user activity using CGEventSourceSecondsSinceLastEventType(kCGEventSourceStateCombinedSessionState, kCGAnyInputEventType).
This worked for me:
-(void) addMyApplicationEventsMonitor {
self.localEventsMonitor = [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskAny handler:^NSEvent * (NSEvent * event) {
// do your stuff here
return event;
}];
}
-(void)dealloc{
//remember add this to remove your monitor
[NSEvent removeMonitor:self.localEventsMonitor];
}
reference here
I am developing an iOS application where need to do some stuff when I have Internet connection and other, when I haven't. If I haven't at some point I will show a message to the user to give me internet and come back. The question it is how to detect the following situation:
the user press the Home button twice, goes to multitasking , Settings and will connect to internet
the user comes back with multitasking to my app, but doesn't press anything
I know I will get callbacks to the AppDelegate:
- (void)applicationDidEnterBackground:(UIApplication *)application
- (void) applicationDidBecomeActive:(UIApplication *)application
but the code ( it is not started by me) it is very big, and I don't want to handle there the UIViewController needs, if there is any alternative.
My UIViewController's - (void)viewDidAppear:(BOOL)animated it isn't called when the user came back.
The breakpoint it is not hited for sure!
Any usable ideas, except in AppDelegate?
You can use the notification center to listen to applicationDidEnterBackground within the view controller:
[[NSNotificationCenter defaultCenter] addObserver: self
selector: #selector(handleEnteredBackground:)
name: UIApplicationDidEnterBackgroundNotification
object: nil];
Do this in viewDidLoad. Similarily for applicationDidBecomeActive.
Don't forget to remove yourself as an observer in viewDidUnload.
The application delegate is the correct place to be handling application state changes, but just because that is the case, it doesn't mean you must put all the logic that is triggered by the application state change in there.
Put the logic where it belongs. If it's networking code, that's not in the application delegate and it's not in the view controller, it's in a separate class. Then look into ways of tying the different parts of your application together. In most cases, notifications, KVO and the shared instance pattern are good approaches to take.
I'm using addGlobalMonitorForEventsMatchingMask to listen to events in Cocoa:
[NSEvent addGlobalMonitorForEventsMatchingMask:NSLeftMouseDraggedMask
handler:^(NSEvent *event) {
NSLog(#"Dragged...");
}];
Though I would like to know if I'm dragging/moving a window (and which window that is, I can find the focused window though when holding command and dragging a window it doesn't get focus as far as I know.)
So, can I detect whether or not I'm dragging a window?
Update:
I now have a class: "SATest : NSObject <NSWindowDelegate>" in which I implement the windowDidMove method (and later perhaps windowWillMove too.) Though, now the next step would be attaching this to a window, right? So my question now is: How do I attach the delegate to all windows of all apps?
Update 2:
I now can find a list of all open windows on the screen:
AXUIElementRef _systemWideElement;
_systemWideElement = AXUIElementCreateSystemWide();
CFArrayRef _windows;
AXUIElementCopyAttributeValues(_systemWideElement, kAXWindowsAttribute, 0, 100, &_windows);
Now I have to iterate over the windows, and of each get it's NSWindow so I can add my delegate to it: [window setDelegate:self];
Update 3: To be clear, this question is about detecting the dragging of ALL windows of ALL apps. Not only the windows of my own app.
Also, I'm very new to this event and window management stuff, so no need to keep your answer short I'm happy to read a lot :P
Thanks!
-P
To find out if a window is being dragged you need to have an object that acts as the delegate of the window by responding to the following messages of the NSWindowDelegate protocol:
windowWillMove - this tells the delegate that the window is about to move.
windowDidMove - this tells the delegate that the window has moved.
You can retrieve the NSWindow object in question by sending object to the notification parameter sent to these methods:
e.g.
NSWindow draggedWindow = [notification object];
More information can be found here.
Update:
In response to your request about getting this information for all windows the NSApplication class provides a method which returns an array of all windows owned by the application. The typical way of getting this information is to use one of the NSApplicationDelegate methods to get a reference to your application object.
For example, in your app delegate (pseudocode):
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSApplication * app = [aNotification object];
// you now have a reference to your application.
// and can iterate over the collection of windows and call
// [window setDelegate:self]; for each window.
}
Note that you will need to add / remove you delegates as windows are added and removed. The best method for doing this is – applicationDidUpdate:.
This should be enough to get you started solving your problem.
As suggested by Benjamin the answer lies in the accessibility API. I was looking around in this for a while, even before I asked this question, but never got it to do what I wanted. I now have found a pretty nice solution.
At a high-level I do the following:
Listen to the mouse down event and remember both on which window you clicked and it's location.
Listen to the mouse up event and check if the location has changed, if so you know you moved a window
You can do something similar for the size if you also want to know if you resized. There might be a better solution, but after days of trying stuff this is the only way I got it to work the way I wanted.
Hope this helps anyone who was looking for something similar.
-Pablo
I use sharekit with mail/twitter/facebook and I am really new to objective-c. sharekit works well and sends my images like it should.
in my app I have a screenshot function. I want the app to 'freeze' when a screenshot is taken, stopping to send any shake- or touch-event to the scene behind the sharekit-action.
in my screenshot-layer I have three buttons which call the shareItem-methods of their specified service, like
[SHKTwitter shareItem:item];
vereything works fine 'till here. but now when the sending is finished (or canceled or errored) I need the app to 'unfreeze', sharekit should tell my app that it is allowed to listen to any touch- or shake-action again.
I am sorry but I think I don't understand the concept of using the delegate here. I mean, is 'sendDidFinish' meant to be inside a delegate? and if so, how could I tell sharekit who is its delegate? or do I have to edit the send-service classes (like SHKItem or SHKFacebook) itself?
please don't downrate me for this question. I really want to get behind this mystery...
SHKTwitter inherit from SHKOAuthSharer, who inherit from SHKSharer. SHKSharer has a delegate protocol called "SharerDelegate".
So you can use an instance of SHKTwitter, then set it's delegate as :
shkTwitterInstance.shareDelegate = yourDelegateObject.
And implement the delegate method
- (void)sharerFinishedSending:(SHKSharer *)sharer;.
Try that.
EDIT (OTHER, AND MORE POPULAR, SOLUTION)
Also, you can suscribe your object to "SHKSendDidFinish" notification from SHKTwitter object.
[[NSNotificationCenter defaultCenter] addObserver:yourObject selector:#selector(theMethodthatYouWantToExecuteWhenTheNotificationIsRaised:) name:#"SHKSendDidFinish" object:shkTwitterObject];
I want to save my data before terminating, so my AppControll class conforms the NSApplicationDelegate protocol, and declared the method; and in the interface builder I bound the window's delegate outlet to AppController, but I cannot get the method invoked.
Where I am wrong, what should I do?
Are you terminating the app from Xcode? Alternatively, is sudden termination enabled in your Info.plist?
Either of these will cause a SIGTERM signal to be sent to the application, terminating it immediately, with no chance for the NSApplication instance to send its delegate an applicationWillTerminate: message. (This is the point of sudden termination: Your app dies instantly. You can turn it off and on programmatically for times when this would be bad.)
Try quitting your application within itself (the Quit menu item in your Application menu), or using the Dock to quit it (right-click on your application's tile and choose “Quit”). As long as sudden termination is disabled (or never was enabled), either of these will cause your application object to send the applicationWillTerminate: message.
Also check that your delegate is getting sent other application-delegate messages, such as applicationWillFinishLaunching:, and make sure you hooked up the outlet in the correct nib (your MainMenu nib).
Did you remember to add the handler to the application?
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(applicationWillTerminate:)
name:UIApplicationWillTerminateNotification object:app];
Is multitasking still enabled? That could be the problem - tapping the home button doesn't cause applicationWillTerminate: to be called if the app goes into the background.
I'm assuming this question applies to macOS apps (as it mentions NSApplicationDelegate).
By default, Xcode 11 (and maybe earlier versions?) includes the NSSupportsSuddenTermination property in new applications' Info.plist file:
...
<key>NSSupportsSuddenTermination</key>
<true/>
...
This property is associated with the enableSuddenTermination and disableSuddenTermination pair of methods in the ProcessInfo (NSProcessInfo) class.
The relevant part of ProcessInfo documentation states:
Sudden Termination
macOS 10.6 and later includes a mechanism that allows the system to log out or shut down more quickly by, whenever possible, killing applications instead of requesting that they quit themselves.
Your application can enable this capability on a global basis and then manually override its availability during actions that could cause data corruption or a poor user experience by allowing sudden termination. Alternately, your application can just manually enable and disable this functionality.
In other words, when NSSupportsSuddenTermination is true, when the user tries to quit the application (directly or indirectly), macOS terminates it, instead of requesting it to quit. This bypasses any events that would otherwise be triggered during a regular quit request.
The good new is that you can either disable that in the Info.plist file, or manually override it, according to your application's needs, by calling ProcessInfo.processInfo.disableSuddenTermination().
In applicationWillFinishLaunching: add:
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(applicationWillTerminate:)
name:UIApplicationWillTerminateNotification object:nil];