Question

我正在做一个项目，我必须从两个单独的URL中获取数据。这些URL包含两个不同地方的天气json。我正在使用UISegmentedControl在两个位置之间切换并在UITableView中显示数据。我正在使用Core Data，因此获取了json并将数据存储在coredata中，然后我使用fetchedResultsController。

我的问题是，当我从显示第一个城市的天气数据的segment1更改为应显示第二个城市的数据的segment2时。它什么都不做，只显示从第一个URL获取的数据。

以下是代码的片段 -

这是我的分段控制IBAction

- (IBAction)segmentedControlAction:(UISegmentedControl *)sender {
    //for Sydney Weather
    if (sender.selectedSegmentIndex == 0) {
        [self refreshDataWithURL:sydneyWeatherURL atLocation:@"Sydney"];
        NSLog(@"SYDNEY");
    }
    //for Mosman weather
    else if (sender.selectedSegmentIndex == 1) {
        [self refreshDataWithURL:mosmanWeatherURL atLocation:@"Mosman"];
        [self.tableView reloadData];
        NSLog(@"MOSMAN");
    }
}

这是上面代码中使用的refreshDataWithURL方法 -

- (void)refreshDataWithURL:(NSString *)stringURL atLocation:(NSString *)location {

    self.managedObjectContext = [CoreDataManager sharedInstance].managedObjectContext;

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    NSURL *weatherURL = [NSURL URLWithString:stringURL];
    GetWeatherData *getWeatherData = [[GetWeatherData alloc] initWithURL:weatherURL andContext:self.managedObjectContext];

    NSLog(@"Fetching Data for %@", location);
    [getWeatherData getWeather];
    [self.tableView reloadData];
}

这是我的fetchedResultsController -

- (NSFetchedResultsController *) fetchedResultsController {
if (_fetchedResultsController != nil) {
    return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entityDescription  = [NSEntityDescription entityForName:@"DailyForecast" inManagedObjectContext:self.managedObjectContext];

[fetchRequest setEntity:entityDescription];

[fetchRequest setShouldRefreshRefetchedObjects:YES];
//Get the latest weather data
NSDate *currentdate = [NSDate date];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(date >= %@)", currentdate];
[fetchRequest setPredicate:predicate];

//order the result from newest to oldest
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"date" ascending:YES];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];

[fetchRequest setFetchBatchSize:30];

NSLog(@"FETCH REQUEST --- %@", fetchRequest);

NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"date" cacheName:nil];

_fetchedResultsController.delegate = self;
self.fetchedResultsController = theFetchedResultsController;
[[[self fetchedResultsController] managedObjectContext] performBlock:^{
    NSError *error = nil;
    BOOL success = [theFetchedResultsController performFetch:&error];

    if (!success) {
        NSLog(@"Error: %@, Error Description: %@", error, [error userInfo]);
        abort(); //Fail
    } else {
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            [self.tableView reloadData];
        }];
    }
}];

return _fetchedResultsController;

}

还有其他frc委托方法。我在其他主题中读到应该有两个应该处理这两个URL的managedObjectContexts，但我不知道如何做到这一点。

这是GetWeatherData .m文件 -

- (void)getWeather {
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:_yahooApiURL cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:30.0];
NSURLResponse *urlResponse;

NSError *error;
//Fetch data from the URL

NSData *urlData = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&urlResponse error:&error];

UIAlertView *alertView;
if (urlData != nil) {
    NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:urlData options:NSJSONReadingAllowFragments error:&error];

    NSArray *jsonArray = [[[[[jsonDict objectForKey:@"query"] objectForKey:@"results"] objectForKey:@"channel"] objectForKey:@"item"] objectForKey:@"forecast"];

    NSString *location = [[[[[jsonDict objectForKey:@"query"] objectForKey:@"results"] objectForKey:@"channel"] objectForKey:@"location"] objectForKey:@"city"];

    for (NSDictionary *dictionary in jsonArray) {
        [DailyForecast getForecastWithWeatherAPI:dictionary forLocation:location inManagedObjectContext:_managedObjectContext];
    }

} else {
    alertView = [[UIAlertView alloc] initWithTitle:@"Error" message:@"There is an error in connecting to the internet" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

    [alertView show];
}

}

任何人都可以提供帮助，非常感谢您的帮助。

提前致谢。

UISegmentedControl不会更改从fetchedResultsController获取的值

0 个答案: