get graph Facebook NSDictionary no Data - ios

Question

view.m
#interface ViewController ()
{
NSMutableArray *fbData,*userInfoArray;
NSString *name;
NSString *picture;
NSString *source;
NSMutableArray *myObject;
NSDictionary *dictionary,*userData;
}
code is describeDictionary function
void describeDictionary (NSDictionary *dict)
{
NSArray *keys;
int i, count;
id key, value;
keys = [dict allKeys];
count = [keys count];
for (i = 0; i < count; i++)
{
key = [keys objectAtIndex: i];
value = [dict objectForKey: key];
NSLog (#"Key: %# for value: %#", key, value);
}
}
code is Data
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
[request startWithCompletionHandler:^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"]; // The result is a dictionary
describeDictionary(userData);
}
}];
code is not Data
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
[request startWithCompletionHandler:^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"]; // The result is a dictionary
}
}];
describeDictionary(userData);
Data should be identical
help me please i am get Facebook graph api
To retrieve the data used But not available
I do not know what to do then. Find out how to do it.

Answer 1

In your last code block:
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
[request startWithCompletionHandler:^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"]; // The result is a dictionary
}
}];
describeDictionary(userData);
The describeDictionary(userData); line is in the wrong place and that's why it's nil—you haven't completed the graph object request at the point you call describeDictionary. It should be like this:
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
[request startWithCompletionHandler:^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"]; // The result is a dictionary
describeDictionary(userData);
}
}];
To explain further, look at your original code:
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
[request startWithCompletionHandler:^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"]; // The result is a dictionary
}
}];
describeDictionary(userData);
This is the sequence in which the code is executed:
First, you create the FBRequest object that will be sent to the Facebook API:
FBRequest *request = [FBRequest requestForGraphPath:#"xxxx?fields=videos.fields(name,picture,source)"];
Next, you tell the request object to call the Facebook API and execute the completion handler when it has finished:
[request startWithCompletionHandler:... ];
Next you call describeDictionary, but userData is neither in scope or initialized. The request's completion handler has not yet been executed therefore userData is nil at this point.
describeDictionary(userData);
The completion handler is called asynchronously when the request has finished. It may have finished successfully—in which case user will not be nil—or there may be an error condition. If there is no error, you assign the value of the videos key of the user object to userData. It is only at this point that can you pass userData to describeDictionary:
^(FBRequestConnection *connection, NSDictionary<FBGraphUser> *user, NSError *error) {
if (!error) {
userData = user[#"videos"];
}
}
You have to call describeDictionary from within the completion handle block.