I have seen in posts around stack overflow that shows snippets of handling GameCenter authentication. However, none of these solutions address any of the problems that real world use cases cover. Namely, the [GKLocalPlayer localPlayer].authenticateHandler is just a call back of the status, and not much else. It provides a view controller, but there are massive inconsistencies in .authenticated, and error states.
There are a few things I am trying to do:
1. Not pop up the game center login until a feature uses it
2. Try to authenticate silently on app launch
3. Provide some info to the user why GameCenter features are not working
4. Provide a recovery mechanism
Namely if there is an error reported how can I show the login dialog anyways?
I get this error with no viewController:
Case 1:
Error in GameCenterManager::authenticateLocalPlayer [The Internet connection appears to be offline.]
Despite its error message, the device is completely online, as safari loads cnn.com just fine.
Case 2:
Someone closes the login screen because they are not ready, in which case .authenticated comes back as true, viewController remains at nil, yet all game center calls will fail. Why is the [GKLocalPlayer localPlayer].authenticated set to true when it isn't?
Case 3:
Error in GameCenterManager::authenticateLocalPlayer [The operation
couldn’t be completed. (NSURLErrorDomain error -1009.)]
This keeps occurring yet there is nothing the app can do for the user. In this case what should the messaging be? Switch apps to Game Center and login there?
Case 4:
Error in GameCenterManager::authenticateLocalPlayer [The requested
operation has been canceled or disabled by the user.]
This happens if the user cancels the viewController the app was told to present by apple. Yet, there is also no recovery or detecting this state.
Case 5:
Error in GameCenterManager::createMatch [The requested operation could
not be completed because local player has not been authenticated.]
This happens if the user was logged in, but for whatever reason logs out of GameCenter then returns to the app. The app will be told the user is still authenticated when it is clearly not, yet there are no calls I can make to bring up another login.
So essentially, if GameCenter doesn't just silently work, what are we to do as app designers? Alert view and tell them to go login using the game center app and restart the app?
Here is my authentication code:
//******************************************************
// Authenticate
//******************************************************
-(void)authenticateLocalPlayer:(bool)showLogin
{
if( showLogin && self.loginScreen != nil )
{ [[WordlingsViewController instance] presentViewController:self.loginScreen animated:YES completion:nil]; }
if( [GKLocalPlayer localPlayer].isAuthenticated )
{
NSDLog(NSDLOG_GAME_CENTER,#"GameCenterManager::authenticateLocalPlayer LocalPlayer authenticated");
}
__weak GameCenterManager* weakSelf = self;
[GKLocalPlayer localPlayer].authenticateHandler = ^(UIViewController *viewController, NSError *error)
{
if (error != nil)
{
NSDLog(NSDLOG_GAME_CENTER,#"Error in GameCenterManager::authenticateLocalPlayer [%#]", [error localizedDescription]);
}
else
{
if (viewController != nil)
{
NSDLog(NSDLOG_GAME_CENTER,#"GameCenter: No authentication error, but we need to login");
weakSelf.loginScreen = viewController;
}
else
{
if ( [GKLocalPlayer localPlayer].authenticated )
{
NSDLog(NSDLOG_GAME_CENTER,#"GameCenter localPlayer authenticated");
weakSelf.gameCenterAvailable = YES;
weakSelf.localPlayer = [GKLocalPlayer localPlayer];
[weakSelf retrieveFriends];
[weakSelf loadPlayerPhoto:weakSelf.localPlayer];
for ( id<GameCenterDelegate> listener in weakSelf.listeners )
{ [listener onPlayerAuthenticated]; }
}
else
{
weakSelf.gameCenterAvailable = NO;
}
}
}
};
}
This function is called twice: once at app startup to hopefully create a valid login state, and 2nd if the user is not authenticated and they try to use an app feature that requires game center. In this app, it is creating a turn based match or viewing friends
You're encountering many of the same complaints I have about the Game Center API. I've been trying to achieve the same 4 things you are. The TL;DR version: Game Center simply doesn't support it. >< But there are some things you can do to reduce the pain.
One general thing that helped me: make sure to check both the NSError as well as it's .underlyingError property. I've seen several cases where the NSError is too vague to be helpful, but the underlying error has more specific details.
Case 1: Can you share the error domain and error code for the both the NSError and the underlyingError?
Case 2: I have an open bug with Apple on this, for a looooong time. There are several cases, including being in Airplane mode, where the authentication fails but .authenticated returns true. When I wrote a bug on this, Apple closed it saying this was "by design" so players could continue to play the game using any previously cached data. So, I appended the bug with several scenarios where cached data causes significant problems. My bug was re-opened and has sat there ever since. The design philosophy seems to be: "well, just keep going and maybe it will all work out in the end." But it doesn't work out in the end, the user gets stuck, unable to play and they blame my game, not Apple.
The only mitigation I have found is exactly what you're already doing: Always always always check the NSError first in the authentication handler. The view controller and .authenticated are totally unreliable if an error has been set.
If there is an error, I pass it to one dedicated error handler that displays alerts to users and tells them what they need to do to recover.
Case 3: I have hit -1009 as well. From what I can discern it happens when I have network connection, but Game Center never replied. That could come from any disruption anywhere between my router up-to-and-including Game Center servers not responding. I used to see this a lot when using the GC Test Servers. Not so much now that the test servers were merged into the prod environment.
Case 4: You are 100% correct. there is no in-game recovery. If the user cancels the authentication, that's the end of the line. The only way to recover is to kill the game (not just leave and re-enter) and restart it. Then, and only then, you can present another login view controller.
There are some things you can do to mitigate this, though. It will directly break your #1 goal of delaying login until needed, but I haven't found anything better:
Disable the "start game" button (or whatever you have in your game) until you've confirmed the login succeeded with no errors AND you can successfully download a sample leaderboard from GC. This proves end-to-end connectivity.
If the user cancels the login, your authentication handler will receive an NSError of domain = GKErrorDomain and code = GKErrorCanceled. WHen I see that combo, I put up a warning to the user that they cannot play network games until they've successfully logged in and to login they will have to stop and restart the game.
Users were confused why the "start" button was disabled, so I added an alert there too. I show a button that looks disabled but is really enabled. And when they try to click it, I again present an alert telling them they have to login in to game center to play a network game.
It sucks, but at least the user isn't stuck.
Case 5: This is one of the examples I cited in my bug referred to in case 2. By letting the user think they're logged in when they really aren't, they try to do things they really can't do, and eventually something bad will happen.
The best mitigation I have found for this is the same as Case 4: don't let the user start a session until you see the authentication handler fire with no errors AND you can successfully download a sample leaderboard to prove the network connection.
In fact, doing a search through all of my code bases, I never use .authenticated for any decisions anymore.
Having said all of that, here's my authentication handler. I won't say it's pretty, but thus far, users don't get stuck in unrecoverable situations. I guess it's a case of desperate times (working with a crap API) requires desperate measures (kludgy work arounds).
[localPlayer setAuthenticateHandler:^(UIViewController *loginViewController, NSError *error)
{
//this handler is called once when you call setAuthenticated, and again when the user completes the login screen (if necessary)
VLOGS (LOWLOG, SYMBOL_FUNC_START, #"setAuthenticateHandler completion handler");
//did we get an error? Could be the result of either the initial call, or the result of the login attempt
if (error)
{
//Here's a fun fact... even if you're in airplane mode and can't communicate to the server,
//when this call back fires with an error code, localPlayer.authenticated is set to YES despite the total failure. ><
//error.code == -1009 -> authenticated = YES
//error.code == 2 -> authenticated = NO
//error.code == 3 -> authenticated = YES
if ([GKLocalPlayer localPlayer].authenticated == YES)
{
//Game center blatantly lies!
VLOGS(LOWLOG, SYMBOL_ERROR, #"error.code = %ld but localPlayer.authenticated = %d", (long)error.code, [GKLocalPlayer localPlayer].authenticated);
}
//show the user an appropriate alert
[self processError:error file:__FILE__ func:__func__ line:__LINE__];
//disable the start button, if it's not already disabled
[[NSNotificationCenter defaultCenter] postNotificationName:EVENT_ENABLEBUTTONS_NONETWORK object:self ];
return;
}
//if we received a loginViewContoller, then the user needs to log in.
if (loginViewController)
{
//the user isn't logged in, so show the login screen.
[appDelegate presentViewController:loginViewController animated:NO completion:^
{
VLOGS(LOWLOG, SYMBOL_FUNC_START, #"presentViewController completion handler");
//was the login successful?
if ([GKLocalPlayer localPlayer].authenticated)
{
//Possibly. Can't trust .authenticated alone. Let's validate that the player actually has some meaningful data in it, instead.
NSString *alias = [GKLocalPlayer localPlayer].alias;
NSString *name = [GKLocalPlayer localPlayer].displayName;
if (alias && name)
{
//Load our matches from the server. If this succeeds, it will enable the network game button
[gameKitHelper loadMatches];
}
}
}];
}
//if there was not loginViewController and no error, then the user is already logged in
else
{
//the user is already logged in, so load matches and enable the network game button
[gameKitHelper loadMatches];
}
}];
I've tried everything I can think of but I'm unable to get OpenPrinter API to work in my BasicMsi
prototype BOOL SETUPAPI.OpenPrinterW(
WSTRING, //_In_ LPTSTR pPrinterName,
NUMBER,//_Out_ LPHANDLE phPrinter,
WPOINTER//_In_ LPPRINTER_DEFAULTS pDefault
);
try
OpenPrinterW(szDriverName, Printer, NULL);
catch
Err = GetLastError();
SprintfBox (INFORMATION, "L862Error","Error occured: %i\n\n%s\n\n%s", Err.Number, Err.Description, Err.LastDllError);
endcatch;
I always get a -2147219709 returned, I've also tried using OpenPrinterA and OpenPrinter but same error everytime.
Does anyone have any idea's as to what I may be doing wrong?
I suspect it's this error:
ERROR_PRINTER_DRIVER_ALREADY_INSTALLED
1795 (0x703)
The specified printer driver is already installed
I converted your error number into hex and it's 80040703 which is where I've gotten 703 from (8004 means it's an error in FACIILITY_ITF)
not sure if this helps... but it might get you started. I wonder if this is some sort of problem where msiexec can't see the printer so tries to install it.
I have been searching stackoverflow and Googling for hours. I made a simple project to mess around with Core Data and bindings. It added an entity to the model and it wouldn't work any more. I was getting "This NSPersistentStoreCoordinator has no persistent stores It cannot perform a save operation" whenever I tried to add data to a new document. I followed every piece of advice I could find with no luck.
Finally, I made a new project (NSPersistentDocument based) and I made a new model from scratch. I made sure the model was perfect before I ran the project for the first time.
In WindowControllerDidLoadNib: The project calls a method to add data. Before addData routine, I log the ManagedObjectContext and the ManagedObjectModel. Neither of them are nil.
I am still getting this %$&##! error.
Does anyone have any new ideas about this?
EDIT: Could this be because the new untitled document has never been saved? If so, how do you get around that? Can you save an untitled document? Do you really want to?
I had a similar problem a while back on a file import. Since I had full control, I named and saved the document and then I was able to save the context.
As I indicated in the comment above, at least in Mountain Lion you have to save the document at least once before you can save the context. I did some experiments and the small amount of data that I changed was preserved by autosave without saving the context. I have changed my saveContext method to the following:
- (void)saveContext {
if (![self fileURL]) {
NSLog(#"Can't save context. No file name has been set.");
return;
}
NSError *error = nil;
if (![self.managedObjectContext save:&error]) {
[NSApp presentError:error];
NSLog(#"Error userInfo: %#",[error userInfo]);
abort();
}
}
First off, I should mention that this is my first post on this site. I am trying to teach myself to program iOS and in my google searches for answers I find that I'm constantly directed here. So thank you to all who have contribute here. You have help me a ton already.
I have been going through the Stanford CS193P class and LOVE it. But I'm stuck right now and not sure where to turn.
My problem has been with the UIManagedDocument.
I tired to make a simple app to test my new skills. This is what it does:
A simple accounting app that tracks individual contributions to a fundraising event.
I have a UITabBar that on each tab allows you to:
1. Track the participants (Players) - This will connect to the address book and allow you to add them or just keep them in this app.
2. Manage the events (Events) - You can add, edit or delete events that you will then add participants to and then be able to add what they brought (Bank) in on that event.
3. Settings. - I've added some buttons just to help me figure stuff out now including a reset button that clears all data and a "dummy data" button.
I have three coreData Entities. Players, Events and Bank each with relationships with the other two.
When I first tried to make this app (pre iOS5) I used the appDelegate to create my ManagedObjectContext and pass it around to my viewControllers. That worked. But now I'm supposed to use the UIManagedObjectDocument and not use the AppDelegate. I believe I understand the principle and the integration to iCloud. (I could be wrong)
Using the examples from the class and what I could find online I made a helper class that will provide the first of each of my ViewControllers within my UINavigationControllers the ManagedDocument.
+ (UIManagedDocument *)sharedManagedDocument
{
static UIManagedDocument *sharedDocument = nil;
NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
url = [url URLByAppendingPathComponent:#"DefaultAppDatabase"];
// url is "<Documents Directory>/<DefaultAppDatabase>"
// Create the shared instance lazily upon the first request.
if (sharedDocument == nil) {
sharedDocument = [[UIManagedDocument alloc] initWithFileURL:url];
}
if (sharedDocument.fileURL != url) {
UIManagedDocument *newDocument = [[UIManagedDocument alloc] initWithFileURL:url];
sharedDocument = newDocument;
}
NSLog(#"SharedDocument: %#", sharedDocument);
return sharedDocument;
}
I then had that first ViewController open the document and perform the fetch.
From there I pass whatever NSManagedObject is selected to the next ViewController through the segue.
The problems are when I get to adding or reseting the data. (I'm assuming that if I can get it to work with the "dummy data" button I can get it to work on an individual entry) When I press the "Reset" or "Dummy" button my logs tell me that it was pushed but I don't see any change in the data until I restart the app. Then it shows up perfectly. My guess is I'm not saving the file correctly or I'm not refreshing the tableViews correctly. I made a small attempt at using NSNotification but didn't go to far into it since I couldn't get it to respond to anything. I'm happy to go back down that road if I need to.
This is my save method... pretty much just copied from the default coreData appDelegate.
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.appDatabase.managedObjectContext;
if (managedObjectContext != nil)
{
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
{
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
[self.appDatabase saveToURL:self.appDatabase.fileURL
forSaveOperation:UIDocumentSaveForOverwriting
completionHandler:^(BOOL success){
if(!success) NSLog(#"failed to save document %#", self.appDatabase.localizedName);
if(success) NSLog(#"Success: save document %#", self.appDatabase.localizedName);
}];
}
Paul, the instructor from CS193P, suggested in Assignment 6 to use a helper method to pass around the UIManagedDocument through a block. I get the theory behind blocks but haven't completely wrapped my head around them so I haven't ruled out that my answer may lie there as well.
Thank you so much for any help or pointing me in the right direction to do more research. Sorry this post is so long, I was trying to be as clear as I can.
I was over thinking the whole thing. Alan asked my question perfectly in this post:
How do I create a global UIManagedDocument instance per document-on-disk shared by my whole application using blocks?
The question and the answers cleared everything up.
Thanks
For iPhone 4 , a lot API can not be used any more.
I am looking for alternative solution for UIImageWriteToSavedPhotosAlbum.
ALAssetsLibrary is current solution from Apple in new iOS 4.
Anyone has experience for that and can give some samples, or open source projects ?
Thanks
you need to do something like this -
ALAssetsLibrary* library=[[ALAssetsLibrary alloc] init] ;
// Request to save the image to camera roll
[library writeImageToSavedPhotosAlbum:img.CGImage orientation:(ALAssetOrientation)img.imageOrientation
completionBlock:^(NSURL* assetURL, NSError* error) {
if (error != NULL)
// Show error message...
else // No errors
// Show message image successfully saved
}] ;
Although I'm going crazy trying to figure out how to keep this code compatible with iphone 3 SDK.