Question

您能帮助我如何获取用户信息。

  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
        }

    }];

上面描述的代码 - 异步？如何让它同步？告诉我有关机制或告诉我在哪里阅读。谢谢！

Answer 1

您可以在此网站上阅读有关 Facebook SDK 的所有内容：https://developers.facebook.com。

他们不提供同步API，我甚至不知道您可能需要它的原因。但如果你真的这样做，你可以做一些解决方法。见实施：

__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

结果符合 FBGraphUser 协议。因此，如果您没有包含 first_name 键的值，则用户不会指定它。您可以在调试器中打印结果，看看它是什么。

Answer 2

您可以使用其他方法来解决您的问题： 1）将name命名为property：__block NSString * name 2）将您需要执行的代码移动到单独的方法，如：

- (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

正如我在之前的回答中澄清的那样，你需要在内部使用名称＆＃34;否则＆＃34;声明。请调试以获得更多理解。所以我们有：

- (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

好像你完全搞砸了。试试这段代码，但请务必理解：

- (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
    }
}

所以过了一段时间你需要进入日志：名字来自服务器：first_name：某个名字我可以使用first_name的名字：某个名称

ios facebook用户信息

4 个答案: