I am creating a application UIPasteboard with my app's identifier as a name (e.g. com.example.app.pboard) as suggested in the docs.
All the copying and pasting works, but the damn thing never goes away. I set its persistent property explicitly to NO every time I access it to copy something onto it, and I even call UIPasteboard's +removePasteboardWithName: every time my app starts.
But every time I look at it, the most recent thing I copied onto it is always there, despite app restarts.
What gives?
No idea why what you are trying isn't working, here are two guesses and a possible solution:
Removing the paste board may be expected to be executed on exit from the app, so it doesn't execute until the app is terminated or backgrounded?
Calling remove and then asking for the items may be recreating it again in the same "place" so the items still remain.
You could perhaps solve this by setting the pasteboard's items to nil when leaving or entering the app.
You can set UIPasteboard to persistent. Accord to Apple's document,
setPersistent:
A Boolean value that indicates whether the pasteboard is persistent.
When a pasteboard is persistent, it continues to exist past app terminations and across system reboots. App pasteboards that are not persistent only last until the owning (creating) app quits. The system wide general pasteboard is persistent. Named, app-specific pasteboards are not persistent.
Update: For iOS 10, UIPasteboard set persistence automatically.
Note
Starting in iOS 10, the system sets pasteboard persistence automatically. If you try to set the setPersistent: property on a pasteboard, Xcode issues a deprecation warning.
Instead of named persistent pasteboards, use shared containers, as described in the Overview section of this document.
Related
According to documentation, RestorableBool class is a RestorableProperty that knows how to store and restore a bool. One example of RestorableBool is given by flutter itself in the flutter gallery project.
The same result can be achieved by using simple boolean. Click here to get the code of same screen using simple bool.
Is there any special benefits for RestorableBool over usual bool or is there any special context at which we have to use RestorableBool?
Anyone to help?Thanks in advance.
Mobile operating systems fool you into thinking all the apps you have open are actually running. But they are not. The topmost is running, all others are killed. Their last screenshot is kept to uphold the illusion of being able to hold multiple apps open.
When you "switch apps", what happens is that the app that wasn't in the foreground is opened and it's state is restored from memory.
If you don't do anything, your app cannot handle this and will just start as if it was started from scratch.
In Flutter, the Restoration Manager can help you store your state and restore your state. Other options are available, I think hydrated_bloc is probably useful if you are working with bloc patterns.
The example in your code doesn't do the same thing, well it does in your code, but it wouldn't in all cases.
The difference is that RestorableBool is reset to it's initial state, even if it is already in that state, meanwhile your code flips the bool to the opposite value.
I have created a Service in Cocoa which grabs the selected Text and sends the result back to my Main App, so i can handle it there ( Couldn't find any other way to get current selection), now that the Service works and appears in the Service Menu, i tried to invoke the Service from my parent App to get current selection, after some goggling around i found this snippet:
NSPasteboard *pboard = [NSPasteboard pasteboardWithUniqueName];
[pboard declareTypes:[NSArray arrayWithObject:NSStringPboardType] owner:nil];
NSPerformService(#"PCB", pboard);
This one works as far as it triggers my Service, the Problem here is it redefines the NSPasteboard, so my service doesn't get the selected text, but a NIL Value Pasteboard which is blank, how can i prevent this?
And does someone know how to convert a .service bundle into an .app bundle that performs itself and sends the data and kills itself after finish?
thx for help
You want to get the text that is selected in another application, right? Probably in the front application, while your app is in the background.
For this to work, you'd have to have the Service be invoked by the front application. If you invoke it from your app in the background, it can't access the front app's text field that contains the selected text. Instead, it'll try to find a text field in your own app's responder chain (I believe – someone correct me if I'm wrong on this detail).
But for your code to run in the app's process, you'll have to inject it somehow, which is - out of security concerns - mostly prohibited by OS X, and especially with sandboxed apps.
There are ways to accomplish code injection, one that 1Password and other popular tools use it through an osax extension. But that's an entirely different topic.
Once you have your code running inside the other app's process, you should be able to copy the selected text (provided it's a Cocoa app) with [NSTextView writeSelectionToPasteboard:types:]. I haven't tested this myself, though, so this is just an assumption.
From inside NSManagedObjectContext -save: I am getting this message:
Assertion failed: (_Unwind_SjLj_Resume() can't return), function _Unwind_SjLj_Resume, file /SourceCache/libunwind/libunwind-24.1/src/Unwind-sjlj.c, line 326.
Program received signal: “SIGABRT”.
warning: Unable to read symbols for
/Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1
(8C148)/Symbols/Developer/usr/lib/libXcodeDebuggerSupport.dylib
(file not found).
This happens when I delete an Experiment object with to-many with Run which has to-many with Sample which has to-one with Data. Experiment also has to-many with Page which has to-many with Display which has to-many to Run. I mention this to point out the cyclical nature of the graph. Here is a simplified graph of model:
An Experiment a top level entity with which the user interacts. An Experiment contains multiple Run objects. A Run is a collection of data starting at a particular time and ending at a later time. Since data can be collected from multiple sources simultaneously, there is a Sample for each source for each Run. An Experiment contains data and this data needs to be viewed and interacted with. So, each Experiment has some number of Page objects and each Page contains some number of Displays (e.g., graphs, meters). A Display is configured to display some subset of the Runs that belong to the Experiment. So, while an Experiment may contains dozens of Runs, one of its Pages will only display a few of those Runs at a time. The Display entity maintains this list. A Display is not a view. A view will reference a Display object and be notified of changes to the Display object.
I had been using Delete Rules but have now switched to "No Action" delete rules in combination with -prepareForDeletion methods for all of these classes. This change made no difference. In both cases, the error message is the same.
Interestingly, when I relaunch the app, all the objects that were marked for deletion have been deleted.
Also, if an Experiment has no Run objects, then deletion works without incidence. For that matter, deleting a single Run from an Experiment also works.
I am hoping that someone has seen something like this and can offer advice on what would cause this. Or, if someone has advice on how to get libXcodeDebuggerSupport.dylib for iOS 4.2.1, that might also be helpful.
Update: I followed advice found here and was able to get Xcode to find libXcodeDebuggerSupport.dylib for iOS 4.2.1. But this did not help at all in diagnosing problem - which persists.
Update 2: After reading a bit and downloading a version of unwind-sjlj.c, it seems that I am dealing with something like an uncaught exception. I am not sure how this helps me...
Update 3: Thanks to Kamchatka, I did something I probably should have done a few days ago: turned on "Stop on Objective-C Exceptions". This allowed me to see that a reference to a deleted object was still being held - and, worse, was key-value observing the deleted object. Fixing this fixed problem and I was able to revert to using delete rules rather than -prepareForDeletion methods.
You should try to activate "Run > Stop on Objective-C exception". It allowed me to find the place where there was an access to an object turned into fault which was the root cause of the problem.
I have 4 database catalogues in my app, i will be switching the four catalogues.
When i start the app, i read the NSUserDefaults and try to load the default catalogue in the memory, but in the first time this doesnt happen. Instead i get null values returned first time just because the DB connection is not successful for some unknown reason, the debugger is unable to go there too.
But the app starts up the next time, the values are fetched successfully.
Please help
If your trying to fetch some necessary data from the user defaults, it might not be there the first time you run the app. You probably need to create a default set of defaults (heh) using:
-[NSUserDefaults registerDefaults:]
...before you query the user defaults for any value.
From User Defaults Programming Topics
The registration domain is a set of
application-provided defaults that are
used unless a user overrides them (the
“default defaults” or “factory
settings”). For example, the first
time you run Xcode, there isn’t an
IndexOnOpen value saved in your
defaults database. Consequently, Xcode
registers a default value for
IndexOnOpen in the
NSRegistrationDomain as a “catch all”
value. Xcode can thereafter assume
that an NSUserDefaults object always
has a value to return for the default,
simplifying the use of user defaults.
You set NSRegistrationDomain defaults
programmatically with the method
registerDefaults:.
I have an iPhone app that stores some settings using NSUserDefault standardUserDefaults.
When I add new features to the app I need to add new default settings and so I have to migrate/upgrade the NSUserDefaults. For now, I just store the version number and check this when the app is launched. It has quickly become very messy as I have to add lots of if statements. I cannot assume that the user is just upgrading from the previous version but perhaps even a couple of versions before.
I like the way that CoreData seems to handle migrating table changes but I want to provide 2.2.1 SDK compatibility and of course CoreData is not the same thing as NSUserDefaults.
Any suggestions or best practices?
Hmm… I wouldn't "upgrade" the user defaults in this way, but instead query NSUserDefaults as usual, only if the default isn't set (objectForKey will return nil in that case), use a default value (which may then be written back to the user defaults to save time the next time). Since you'll have to do this every time a "new" default (i.e. one that didn't exist in 1.0) is read, I advise doing a wrapper class/file that does this, this way the code is written only once for each "new" default.
Also, while the question/problem is different, this answer works just as well in your case.