ios Facebook用户信息

Question

Can you help me how can I get user info.

  NSString *name;
[FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error)
    {
        if (!error)
        {
            // Success! Include your code to handle the results here
           name = [result objectForKey:@"first_name"]; // Error!!! how to get data from this handler
        }
        else
        {
            // An error occurred, we need to handle the error
            // See: https://developers.facebook.com/docs/ios/errors
        }

    }];

Code described above - asynchronous? How to make it synchronous? Tell me about the mechanism or tell me where to read. Thank you!

Answer 1

You could read everything about Facebook SDK on this site: https://developers.facebook.com .

They don't provide synchronous API and I don't even know why you might need it. But if you really do you can do some workaround. See implementation:

__block id result = nil;
dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

[FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id theResult, NSError *error) {
    result = theResult;
    dispatch_semaphore_signal(semaphore);    // UPDATE: dispatch_semaphore_wait call was here, which is wrong
}];

dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
NSLog(@"%@", result);// this code will be launched after you've received response from Facebook

Result conforms FBGraphUser protocol. So if you it doesn't contain value for first_name key, user wouldn't have specified it. You could print result in debugger and see what it is.

Answer 2

You can use additional method to solve your problem: 1) make name as property: __block NSString *name 2) move you code, that you need to perform, to separate method, like that:

- (void) methodWithComplitionHandler
{
name = nil;
[FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error)
{
        if (!error)
        {
           name = [result objectForKey:@"first_name"]; 
        }
        else
        {
        }
}];
[self futherProcessMethod];
}

- (void) furtherProcessMethod
{
if (self.name == nil)
    {
        [self performSelector:@selector(furtherProcessMethod) withObject:nil afterDelay:3.0]; // here set appropriate delay
    }
    else
    {
      // do some with name;
    }
}

Answer 3

As I clarify in previous answer, you need to work with name inside "else" statement. Please, debug for more understanding. So we have:

- (void) SetUserData
{
    [FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error)
    {
        if (!error)
        {
            self.first_name  = [result objectForKey:@"first_name"];
        }
        else
        {
        }
    }];
    [self furtherProcessMethod];

}


- (void) furtherProcessMethod
{
    if (self.first_name == nil)
    {
        [self performSelector:@selector(furtherProcessMethod) withObject:nil afterDelay:30.0]; // here set appropriate delay
    }
    else
    {
        NSLog(@"first_name: %@", self.first_name); 
    }
}

Answer 4

Seems like you totally mess up. Try this code, but be sure, your understand it:

- (void) SetUserData
{
    [FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id result, NSError *error)
    {
        if (!error)
        {
            self.first_name  = [result objectForKey:@"first_name"];
            NSLog(@"First name just came from server: first_name: %@", self.first_name); 
        }
        else
        {

        }
    }];
    [self furtherProcessMethod];
}


- (void) furtherProcessMethod
{
    if (self.first_name == nil)
    {
        // this is not recursion, do not miss that!!
        [self performSelector:@selector(furtherProcessMethod) withObject:nil afterDelay:2.0]; 
    }
    else
    {
        NSLog(@"First name that I can work with first_name: %@", self.first_name); 
// here you can handle you first_name, after it came
    }
}

So after some time you need to get in log: First name just came from server: first_name: some name First name that I can work with first_name: some name