BOOL active = [[apIndicators[i] valueForKey:@"isActive"] boolValue];
if (active){
// do whatever
}
If those apIndicators are all NSDictionaries you could use the fast enumerator to simplify the loop quite a bit as well.
for (NSDictionary *apIndicator in yourArray){
BOOL active = [[apIndicator valueForKey:@"isActive"] boolValue];
if (active){
// do whatever
}
}