Is it possible to tag blocks? - iphone

Question

I am working on a turn based iOS game and trying to populate my list of games the player is participating in.
for (unsigned i = 0; i < [matches count]; i++)
{
// Only load data for games in progress.
// NOTE: Might want to handle finished games later.
if ([matches[i] status] != GKTurnBasedMatchStatusEnded)
{
// Send off another block to retrieve the match's data.
[(GKTurnBasedMatch*)matches[i] loadMatchDataWithCompletionHandler: ^(NSData *matchData, NSError *error)
{
// Prepare the game.
Game* game;
if (matchData.length == 0)
{
// If the match data is empty, this is a new game. Init from scratch.
game = [[Game alloc] init];
}
else
{
// Otherwise, unpack the data and init from it.
game = [NSKeyedUnarchiver unarchiveObjectWithData:matchData];
}
game.match = matches[i];
// Load the displayNames for the players.
bool lastIndex = i == ([matches count] - 1);
[self loadPlayerIdentifiersForGame:game intoArray:blockGames lastIndex:lastIndex];
}];
}
}
Unfortunately, I am having an issue where I can't tag each block with its index. That is, i is always 0 by the time the block executes. Is there a way that I can make sure the block knows what i WAS at the time it was launched?

Answer 1

I sidestepped the issue where my UITableView wouldn't reload if the last game was over by doing this instead:
GKTurnBasedMatch* match;
for (int j = ([matches count] - 1); j >= 0; j --)
{
match = matches[j];
if (match.status != GKTurnBasedMatchStatusEnded)
break;
}
bool lastIndex = (matches[i] == match);
[self loadPlayerIdentifiersForGame:game intoArray:blockGames lastIndex:lastIndex];

Answer 2

-(void)someMethod {
...
for (unsigned i = 0; i < [matches count]; i++)
{
// Only load data for games in progress.
// NOTE: Might want to handle finished games later.
if ([matches[i] status] != GKTurnBasedMatchStatusEnded)
[self loadMatch:i of:matches];
}
}
-(void) loadMatch:(int)i of:(NSArray *)matches {
// Send off another block to retrieve the match's data.
[(GKTurnBasedMatch*)matches[i] loadMatchDataWithCompletionHandler: ^(NSData *matchData, NSError *error)
{
// Prepare the game.
Game* game;
if (matchData.length == 0)
{
// If the match data is empty, this is a new game. Init from scratch.
game = [[Game alloc] init];
}
else
{
// Otherwise, unpack the data and init from it.
game = [NSKeyedUnarchiver unarchiveObjectWithData:matchData];
}
game.match = matches[i];
// Load the displayNames for the players.
bool lastIndex = i == ([matches count] - 1);
[self loadPlayerIdentifiersForGame:game intoArray:blockGames lastIndex:lastIndex];
}];
}

Answer 3

the simplest way is to pass a third parameter containing the tag..
And I suggest to use typedef.. to better write code (and let autocompletion work for you..)
typedef void (^CompletionBlock)(NSInteger tag, NSData * data, NSError *err);
and use CompletionBlock when defining loadMatchDataWithCompletionHandler.