Can an asynchronous task be run in a loop? (in iOS) - ios

Question

basically I'm using firebase to query a user's 'status' property and doing so in a do/while loop.
If the status property is free then i want to break the loop and continue with the rest of the method. If the status property is not free then I want to query firebase again for a new user until a free user is found.
My firebase code works fine outside the loop but doesn't seem to be called inside of it. Here is the loop:
__block uint32_t rando;
self.freedom = #"about to check";
do {
//check if free
[self checkIfFree:^(BOOL finished) {
if (finished) {
if ([self.freedom isEqualToString:#"free"]) {
//should break loop here
}
else if ([self.freedom isEqualToString:#"matched"]){
//get another user
do {
//picking another random user from array
rando = arc4random_uniform(arraycount);
}
while (rando == randomIndex && rando == [self.randString intValue]);
self.randString = [NSString stringWithFormat:#"%u", rando];
[users removeAllObjects];
[users addObject:[usersArray objectAtIndex:rando]];
self.freeUser = [users objectAtIndex:0];
//should repeat check here but doesn't work
}
else{
NSLog(#"error!");
}
}
else{
NSLog(#"not finished the checking yet");
}
}];
} while (![self.freedom isEqual: #"free"]);
And here's my firebase code:
-(void)checkIfFree:(myCompletion) compblock{
self.freeUserFB = [[Firebase alloc] initWithUrl:[NSString stringWithFormat: #"https://skipchat.firebaseio.com/users/%#", self.freeUser.objectId]];
[self.freeUserFB observeEventType:FEventTypeValue withBlock:^(FDataSnapshot *snapshot)
{
self.otherStatus = snapshot.value[#"status"];
NSLog(#"snapshot info %#", snapshot.value);
if ([self.otherStatus isEqualToString:#"free"]) {
self.userIsFree = YES;
self.freedom = #"free";
}
else{
self.userIsFree = NO;
self.freedom = #"matched";
}
compblock(YES);
}];
}
Thanks!

Answer 1

I am not sure I understand correctly your question.
If you want to run your completion code again till some condition is matched (in this case [self.freedom isEqualToString:#"free"]) you can do the following (removing the do - while):
void( ^ myResponseBlock)(BOOL finished) = ^ void(BOOL finished) {
if (finished) {
if ([self.freedom isEqualToString: #"free"]) {
return;
} else if ([self.freedom isEqualToString: #"matched"]) {
//get another user
do {
//picking another random user from array
rando = arc4random_uniform(arraycount);
}
while (rando == randomIndex && rando == [self.randString intValue]);
self.randString = [NSString stringWithFormat: #"%u", rando];
[users removeAllObjects];
[users addObject:usersArray[rando]];
self.freeUser = users.firstObject;
// Schedule another async check
[self checkIfFree: myResponseBlock];
} else {
NSLog(#"error!");
}
} else {
NSLog(#"not finished the checking yet");
}
};
[self checkIfFree: myResponseBlock];