Hi I am trying to switch between the rear and front facing cameras if i start he session with the front facing camera it works but with the other way way round the AVCapturepreview layer is not visible and just presents a blank screen.
First stop the preview session.
When stopped (use the delegate for this) set the camera device you want and restart the preview session.
In code:
[[PBJVision sharedInstance] stopPreview];
//implement the following deluge ate
- (void)visionSessionDidStopPreview:(PBJVision *)vision{
vision.cameraDevice = PBJCameraDeviceFront;
[vision startPreview];
}
I'm working with Game Center Kit, how can I get the image of game center user(my friend, or anyone else) thnx
There is an asynchronous method to load either a small or normal sized player image (only available in iOS5):
- (void)loadPhotoForSize:(GKPhotoSize)size
withCompletionHandler:(void (^)(UIImage *photo, NSError *error))completionHandler
Waiting for Game Center authentication to complete is a bad idea since it can take a very long time. Moreover, authentication is done not just at game launch but whenever you switch back to a game via fast app switching.
But not waiting for authentication presents problems:
how do you resume a saved game if you don't know who the player is? Ideally, a saved game would be associated with who was playing so you don't have someone resuming another person's game.
how do you resume a game after an app switch back if you don't know who the player is (the player may have changed via the Game Center app)?
a Game Center log in alert might pop up in the middle of an action game (it is not paused)
what if the game is over before authentication completes? What if the initial authentication completes after a few games have been played? What if the initial authentication completes after an app switch or two (which in turn result in more authentications)?
What is a reasonable approach to handle these problems?
Hmm.. i only authenticate at the start of app.. Its set by yourself when you want to authenticate the player.. You might want to save the player alias when the player is first authenticated.. Means:
sharedData.myName = [[GKLocalPlayer localPlayer]alias];
So when the player app switch and stuff, but is not authenticated, you save data under this player alias.. So when the player is finally authenticated, you send the data to GameCenter
Meaning in your checking GameCenter part..
if(!inGame)
{
[[GKLocalPlayer localPlayer] authenticateWithCompletionHandler:^(NSError *error){
if(error == nil){
if(sharedData.myName ==nil)
{
sharedData.myName = [[GKLocalPlayer localPlayer]alias];
}
else if([[GKLocalPlayer localPlayer]alias] == sharedData.myName)
{
[self sendSavedData];
}
else if([[GKLocalPlayer localPlayer]alias] != sharedData.myName)
{
// create new data or look for other saved data which has the same name..
// set sharedData.myName to current player Name..
}
}
enter code here
I have a "Play Now" button in my app that allows players to be auto-matched with other random players. Maybe I'm missing this somewhere in the docs, but how do I write the code to auto match players?
The Game Center sandbox server has been messed up the last few days, so I'm having a hard time trying different things since I have to guess because the Game Kit docs aren't exactly clear on how to do this. Currently, I have code setup (but untested) to create a match with a friend...
NSArray *playerList = [NSArray arrayWithObject:pid];
GKMatchRequest *request = [[[GKMatchRequest alloc] init] autorelease];
request.minPlayers = 2;
request.maxPlayers = 4;
request.playersToInvite = playerList;
[[self waitingIndicator] startAnimating];
[[GKMatchmaker sharedMatchmaker] findMatchForRequest:request withCompletionHandler:^(GKMatch *match, NSError *error) {
if (error)
{
//handle error
}
else if (match != nil)
{
self.myMatch = match;
//start match code
}
}];
But how do I auto match two random people looking for a game? My guess, since the docs don't say it, or I'm missing it, is that in order to create an auto match, I simply set the playersToInvite property of the match object to nil? If not, how do I create an auto match?
One other question, while we're on the topic, the Game Kit docs site a few common matchmaking scenarios, one of them being...
A player can also create a network
match using the Game Center
application. When they invite a friend
into a multiplayer game, your
application is launched on both
devices, and each copy of your
application receives an invitation to
join the game.
But I can't figure out how to do this in the Game Center app for testing purposes. How does a user create a network match using the Game Center app? I don't see any buttons for that anywhere in the Game Center app.
Thanks in advance for your wisdom!
Ok, now that the sandbox Game Center server is back up, I was able to confirm that auto-matching works by setting the playersToInvite property to nil, or not setting it all.
In a game I am developing using GameCenter, I want to handle the following scenario:
the user starts up the game. He is shown the system alert that prompts him to log on GameCenter. He ignores it for now.
after a while, the user wants to log in to GameCenter and clicks on(for instance) the Leaderboards menu item. He choses cancel instead of Log in, for now.
the process repeats several times. Eventually the user DOES want to log in to GameCenter. He clicks the Leaderboard menu item one more time.
In my tests, I have found that the alert popup raised by the call to "authenticateWithCompletionHandler" (as invoked by Apple's sample GameCenterManager) which suggests to log in to GameCenter only appears a limited number of times(4 or 5). The last time it appears, it says "Game Center Disabled, sign in with the Game Center application to enable"Afterwards". Afterwards, calling authenticateWithCompletionHandler no longer does anything visible -no prompt at all.
Playing FruitNinja I tried to replicate this. However, in their case, the popup saying "Game Center Disabled" does appear every time I click on a GameCenter item(Achievements, for instance).
What I'd like to do is to duplicate the functionality: that is, if you are not logged in to GameCenter, to have the standard game center alert appear all the times you click on the Leaderboard menu item.
Is there a way to learn whether the standard 'log in to game center' alert has appeared, or to force it to appear at all times(and not just the first couple of tries)?
Here's an is an idea to workaround this issue:
No matter if a "GC authenticateWithCompletionHandler"-Request is cancelled
by the user tapping "Cancel" in the dialog
or due to the fact that
GC is disabled on the device (which happens after the user has cancelled the alert-dialog exactly 3 times (in iOS 5 at least))
you will always receive an NSError with code 2 saying "The requested operation has been cancelled.".
The only differentiator that i could find is the time passed between the authenticateWithCompletionHandler-Request and the the execution of the completion-Handler.
So when sending the request i am saving the time:
requestTime = [NSDate date];
and in my completion handler i measure the time lapsed:
NSDate* now = [NSDate date];
CFTimeInterval elapsedTimeSinceAuthenticationRequest = [now timeIntervalSinceDate:requestTime];
NSLog(#"time Elapsed: %f", elapsedTimeSinceAuthenticationRequest);
If the user cancelled the request, the time passed will be significantly longer compared to the time passed if GC cancelled the operation. In my tests, it took a user at least one second to cancel the dialog, whereas a GC-cancelled request took less than 0.1 seconds (on my iPhone 4)
Of course, these values may vary depending on the device the code runs on and on what else the processor is busy with at the moment. One pitfall i already examined is the application launch: If you are sending the authenticationRequest during applicationDidFinishLaunching as suggested by Apple, it took much longer for GC to cancel the request in my case, because the device is busy loading views and whatever is necessary to launch the app.
So let me know if you tried this solution and if it worked for you, as will i once i have done further testing...
The behavior is something to the effect of, after N unsuccessful attempts - disable GameCenter for the app. Restarting the app or going to login in gamecenter itself will get it back online.
I forget which doc I read this in, but there is an Apple doc out there that explains this behavior.
I couldn't find a good answer for this either, so I decided to just replicate the message once the I start getting the cancel error. This is still in development but it basically changes the button callback to display the error alert rather than display the leader-board.
Just a note, not sure if this will be approved or not since I am replicating an Apple error message.
-(void) gcLogin: (id) sender {
[[GKLocalPlayer localPlayer] authenticateWithCompletionHandler:^(NSError *error) {
if(error) {
if([[error domain] isEqualToString:GKErrorDomain] && [error code] == GKErrorCancelled) {
[ResourceManager showAlertWithTitle:#"GameCenter Disabled" message:#"Sign in with Game Center application to enable"];
mGameCenterCancelled = YES;
}
NSLog(#"%#", [error description]);
} else {
[self updateMenu];
mGameCenterCancelled = NO;
}
}];
}
I am playing around with Game Center myself right now I have seen the very same behavior. There is nothing in the documentation saying anything about the dialog only showing up the first couple of times.
In my case I would like a way to tell beforehand if the user is already logged into Game Center, so that I can behave appropriately. But now I can not know this before the dialog is shown to the user.
Since we are running in the sandbox during development this behavior might of course be something that behaves differently during production but this is not an easy thing to find out.
May be the link will helpful (First three paragraphs):
http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/GameKit_Guide/Users/Users.html#//apple_ref/doc/uid/TP40008304-CH8-SW9
The main point is in a rectangle "Important".
I'm facing the same issue. Though I couldn't find a way to enforce poping up the same dialog for logging into Game Center, I did find a way to implement a warning message saying 'gamecenter is disabled' when user clicks on a leaderboard icon:
if([GKLocalPlayer localPlayer].authenticated == NO)
{
// Prompt a warning message alert saying game center is disabled
}
else
{
// Proceed with opening leaderboard
}
Hope this helps!
It appear that iOS will disable Game Center completely and prevent it from prompting after the user chooses to Disable Game Center (the option would appear on your fifth 5th Game Center cancel sign in).
To restore the device to the original state where the login prompt will appear again. Simply sign in using the Game Center app using a normal working Game Center account (non Tester). Once you are in, Sign Out. It should start prompting you again on within your app.