Question

我不明白为什么完成块不起作用。首先我找到当前位置，然后使用纬度和经度从服务器获取数据。我还尝试使用NSURLSessionDelegate进行后台会话，但也没有获得任何数据。

- (void)widgetPerformUpdateWithCompletionHandler:(void (^)(NCUpdateResult))completionHandler {
    // Perform any setup necessary in order to update the view.

    [self updateWidget];
    self.placeImageView.image = [UIImage imageNamed:@"no-image"];
    self.crowdednessLevelImageView.image = [UIImage imageNamed:@"circle-crowd"];
    self.placeImageView.layer.cornerRadius = 10;

    NSUserDefaults *defaults = [[NSUserDefaults standardUserDefaults] initWithSuiteName:@"group.wherepeeps.mostCrowdedPlace.widgert"];
    NSString *coordinateString = [defaults objectForKey:@"CurrentLocationCoordinateString"];
    NSDictionary *responseObject = [defaults objectForKey:@"listOfPlacesForWidget"];
    NSLog(@"responseObject - %@", responseObject);
    if (coordinateString) {
        NSString *stringUrl = [NSString stringWithFormat:@"https://sheltered-fjord-29765.herokuapp.com/api/v1/search?location=%@", coordinateString];
        NSURLSession *mySession = [self configureMySession];
        NSURL *url = [NSURL URLWithString:stringUrl];
        [mySession dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
            NSDictionary *responseObject = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
            NSUserDefaults *defaults = [[NSUserDefaults standardUserDefaults] initWithSuiteName:@"group.wherepeeps.mostCrowdedPlace.widgert"];
            [defaults setObject:responseObject forKey:@"listOfPlacesForWidget"];
            [defaults synchronize];
            NSLog(@"responseObject - %@", responseObject);
            completionHandler(NCUpdateResultNewData);
        }];     

    } else {
        completionHandler(NCUpdateResultNoData);
    }   
}

- (NSURLSession *)configureMySession {
    if (!self.mySession) {
       // NSURLSessionConfiguration* config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:@"com.mycompany.myapp.backgroundsession"];
        NSURLSessionConfiguration* config = [NSURLSessionConfiguration defaultSessionConfiguration];
        // To access the shared container you set up, use the sharedContainerIdentifier property on your configuration object.
        config.sharedContainerIdentifier = @"com.mycompany.myappgroupidentifier";
        self.mySession = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
    }
    return self.mySession;
}

Answer 1

尝试使用persormSelectorOnMainThread在主线程上调用Nsurlsession请求。

在今天的扩展中使用Urlsession

1 个答案: