问题
I am using Social framework for Facebook & Twitter integration. For this I followed this link Everything is working fine except when I app receives ACAccountStoreDidChangeNotification , it crashes. App crashes when
1) I installed app for first time & user don't have Facebook / Twitter account configured in Settings.
2) When I call any method of Facebook / Twitter , it gives me error code 6 as I don't have account configured which is right.
3) I click on HOME button so my app enters background & add account in Settigs.
4) Once I configured account & come back to app , my app launches from background & receives ACAccountStoreDidChangeNotification.
5) In selector of ACAccountStoreDidChangeNotification my account object is nil so my app crashes. So I checked for the nil
Here is my code
#pragma mark - Request Facebook Account Access
-(void)requestFacebookAccountAccess
{
requestType = kNoOpRequest;
// Register for Account Change notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(accountChanged:) name:ACAccountStoreDidChangeNotification object:nil];
self.accountStore = [[ACAccountStore alloc]init];
ACAccountType *FBaccountType= [self.accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierFacebook];
// Set facebook permissions
NSArray *permissions = nil;
// We need to ask for Basic permission first
if (![kUserDefaults boolForKey:FACEBOOK_BASIC_PERMISSION]) {
permissions = @[@"email",@"user_about_me",@"user_location",@"friends_about_me"];
self.isBasicFacebookPermissionsRequested = YES;
}
else {
permissions = @[@"email",@"user_about_me",@"user_location",@"friends_about_me",@"publish_stream"];
}
//use ACAccountStore to help create your dictionary
NSDictionary *dictFacebook = @{
ACFacebookAppIdKey: kFacebookAppIDKey,
ACFacebookPermissionsKey: permissions,
ACFacebookAudienceKey: ACFacebookAudienceFriends
};
[self.accountStore requestAccessToAccountsWithType:FBaccountType options:dictFacebook completion:^(BOOL granted, NSError *error) {
if (granted) {
if (self.isBasicFacebookPermissionsRequested) {
self.isBasicFacebookPermissionsRequested = NO;
[kUserDefaults saveBasicFacebookPermissionsGrantedStatus:YES];
//[self requestFacebookAccountAccess];
}
// User granted permission to Accout
NSArray *accountsArray = [self.accountStore accountsWithAccountType:FBaccountType];
if ([accountsArray count]>0) {
//It will always be the last object with SSO
self.facebookAccount = [accountsArray lastObject];
NSLog(@"In %s::IS MAIN THREAD:- %@",__PRETTY_FUNCTION__,[NSThread isMainThread]?@"YES":@"NO");
if ([self.delegate respondsToSelector:@selector(didFacebookAccountAccessGranted)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didFacebookAccountAccessGranted];
});
}
}
else {
[self showAlertWithTitle:@"Error" andMessage:@"You don't have any Facebook accounts set up yet.Please set a Facebbok account and try again."];
}
}
else {
DLog(@"User denied permission to Accout::Localized Error:- %@",error.localizedDescription);
if([error code]==6) {
[self showAlertWithTitle:@"Error" andMessage:@"Please setup facebook account from Settings"];
if ([self.delegate respondsToSelector:@selector(didFacebookAccountAccessDenied:)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didFacebookAccountAccessDenied:error];
});
}
}
else if ([self.delegate respondsToSelector:@selector(didFacebookAccountAccessDenied:)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didFacebookAccountAccessDenied:error];
});
}
else {
// User denied permission to Account
[self showAlertWithTitle:@"Error" andMessage:[NSString stringWithFormat:@"User denied permission to Accout::Error:- %@",error.localizedDescription]];
}
}
}];
}
#pragma mark - Get Logged In User Info
-(void)getLoggedInUserInfo
{
NSURL *requestURL = [NSURL URLWithString:@"https://graph.facebook.com/fql"];
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"SELECT current_location,uid,name,sex,birthday,email,pic FROM user WHERE uid=me()",@"q", nil];
requestType = kGetLoggedInUserInfoRequest;
[self requestDataUsingURL:requestURL parameters:dict requestMethod:SLRequestMethodGET];
}
#pragma mark - Request Data From Facebook
-(void)requestDataUsingURL:(NSURL*)requestURL parameters:(NSDictionary*)params requestMethod:(SLRequestMethod)reuqestMethod
{
SLRequest *request = [SLRequest requestForServiceType:SLServiceTypeFacebook
requestMethod:reuqestMethod
URL:requestURL
parameters:params];
request.account = self.facebookAccount;
[request performRequestWithHandler:^(NSData *data,
NSHTTPURLResponse *response,
NSError *error)
{
NSDictionary *dictData =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
if(!error)
{
if([dictData objectForKey:@"error"]!=nil)
{
DLog(@"Request Data From Facebook Errro:- %@",dictData);
[self attemptRenewCredentials];
if ([self.delegate respondsToSelector:@selector(didGetFacebookError:)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didGetFacebookError:dictData];
});
}
}
else {
// Process the response
//NSLog(@"Response Dictionary contains: %@", dictData );
if ([self.delegate respondsToSelector:@selector(didPostToFacebook:)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didPostToFacebook:dictData];
});
}
}
}
else{
if ([self.delegate respondsToSelector:@selector(didGetFacebookError:)]) {
dispatch_async(dispatch_get_main_queue(),^{
[self.delegate didGetFacebookError:dictData];
});
}
else {
[self showAlertWithTitle:@"Error" andMessage:@"Some error occured while processing Facebook request"];
}
}
}];
}
-(void)accountChanged:(NSNotification *)notif
{
if (self.facebookAccount!=nil) {
[self attemptRenewCredentials];
}
else {
[self requestFacebookAccountAccess];
}
}
#pragma mark - Attempt to Renew Credentials
-(void)attemptRenewCredentials
{
[self.accountStore renewCredentialsForAccount:(ACAccount *)self.facebookAccount completion:^(ACAccountCredentialRenewResult renewResult, NSError *error){
if(!error)
{
switch (renewResult) {
case ACAccountCredentialRenewResultRenewed:
NSLog(@"Good to go");
[self againRequestFacebook];
break;
case ACAccountCredentialRenewResultRejected:
NSLog(@"User declined permission");
break;
case ACAccountCredentialRenewResultFailed:
NSLog(@"non-user-initiated cancel, you may attempt to retry");
break;
default:
break;
}
}
else{
//handle error gracefully
NSLog(@"error from renew credentials%@",error);
}
}];
}
-(void)againRequestFacebook
{
switch (requestType) {
case kGetLoggedInUserInfoRequest:
[self getLoggedInUserInfo];
break;
case kGetFriendsInfoRequest:
[self getFacebookFriendsInfo];
break;
case kPostToWallRequest:
[self postToFacebookWallInBackgroundForUserId:fbUserIdForPost withParams:paramsToPost];
break;
default:
break;
}
}
#pragma mark - Remove Observer for Notification
-(void)dealloc
{
requestType = kNoOpRequest;
[[NSNotificationCenter defaultCenter] removeObserver:ACAccountStoreDidChangeNotification];
}
But accountChanged method gets called multiple times. What is wrong in this ? How can I handle this situation ? Any kind of help is highly appreciated.
Thanks in advance.
回答1:
I am facing the same problem...so i used a work around by having a BOOL value in NSUserDefaults to execute accountChanged method only once
-(void)accountChanged:(NSNotification *)notif
{
BOOL calledAccountChanged =[[[NSUserDefaults standardUserDefaults] objectForKey:DidAccountChanged] boolValue];
if(!calledAccountChanged)
{
if (self.facebookAccount!=nil) {
[self attemptRenewCredentials];
}
else {
[self requestFacebookAccountAccess];
}
}
}
Then we can change DidAccountChanged value later in the code...
If you have better solution do post it...
来源：https://stackoverflow.com/questions/14982622/handle-acaccountstoredidchangenotification-for-facebook-twitter-in-ios-6