Question

我正在尝试在循环中运行一个块并在NSMutableArray中收集结果。我遇到的问题是，由于它是异步的，我很难找到所有块何时完成执行。我正在尝试将[数组计数]与块调用的数量进行比较。我的想法是，这只会触发一次，但我发现'我做了！'将永远不会被记录或将被多次记录。我也觉得这是一个hacky解决方案，但我想不出更好的方法。

很抱歉长代码块但是我输入了所有需要的代码，所以如果有人想要，他们可以复制＆amp;粘贴并查看我得到的结果。我的问题的实际肉和土豆开始于大约2/3的while循环。

很明显，我是iOS开发的新手，所以欢迎任何其他建设性的批评。

NSDate *now = [NSDate date];

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *zeroOutAfterHourComponents = [gregorian components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit fromDate:[NSDate date]];
NSDate *gregorianNow = [gregorian dateFromComponents:zeroOutAfterHourComponents];

NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay:-7];
//[componentsToSubtract setHour:-24];

NSDate *startingDate = [gregorian dateByAddingComponents:componentsToSubtract toDate:gregorianNow options:0];

NSDateComponents *addAnHourComponent = [[NSDateComponents alloc] init];
[addAnHourComponent setHour:1];
NSDate *startingDatePlusAnHour = [gregorian dateByAddingComponents:addAnHourComponent toDate:startingDate options:0];

CMStepCounter *stepCounter = [CMStepCounter new];
NSOperationQueue *stepQueue = [NSOperationQueue new];
stepQueue.name = @"Step Counter Queue";

__block NSMutableArray *dateKeyAndSccSteps = [NSMutableArray new];

NSTimeInterval time = [now timeIntervalSinceDate:startingDate];
int hours = time / 60 / 60;

// + 1 is added to take account of the current hour
int totalDictionaryCount = hours + 1;

NSLog(@"totalDictionaryCount: %d", hours);
NSLog(@"StartingDate: %@", startingDate);
NSLog(@"StartingDatePlusAnHour: %@", startingDatePlusAnHour);
NSLog(@"Now: %@", now);

while ([startingDate compare:now] == NSOrderedAscending) {
    [stepCounter queryStepCountStartingFrom:startingDate to:startingDatePlusAnHour toQueue:stepQueue withHandler:^(NSInteger numberOfSteps, NSError *error) {

        NSDateFormatter *formatterForDate = [[NSDateFormatter alloc] init];
        [formatterForDate setDateFormat:@"yyyy-MM-dd"];
        NSString *dateKey =[NSString stringWithFormat:@"%@", [formatterForDate stringFromDate: startingDate]];

        [dateKeyAndSccSteps addObject:@[dateKey, @"TestValue"]];

        NSLog(@"array count: %lu - totalDictionaryCount: %d", (unsigned long)[dateKeyAndSccSteps count], totalDictionaryCount);
        if ([dateKeyAndSccSteps count] == totalDictionaryCount){
            NSLog(@"I MADE IT!");
        }
    }];

    startingDate = startingDatePlusAnHour;
    startingDatePlusAnHour = [gregorian dateByAddingComponents:addAnHourComponent toDate:startingDatePlusAnHour options:0];
};
NSLog(@"Finished While Loop: %@", now);

更新 - 2013-12-13

我使用调度组更新了我的while循环。我还改变了stepCounter块以使用[NSOperationQueue mainQueue]。

它有效，但我不确定我是否正确使用它们。

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_group_t group = dispatch_group_create();

while ([startingDate compare:now] == NSOrderedAscending) {

    dispatch_group_async(group, queue, ^{

        [stepCounter queryStepCountStartingFrom:startingDate to:startingDatePlusAnHour toQueue:[NSOperationQueue mainQueue] withHandler:^(NSInteger numberOfSteps, NSError *error) {

            << same existing code as original >>

        }];

    });

    startingDate = startingDatePlusAnHour;
    startingDatePlusAnHour = [gregorian dateByAddingComponents:addAnHourComponent toDate:startingDatePlusAnHour options:0];
};

将结果从while循环中的块收集到NSArray中

0 个答案: