ios - 如何更改sendSynchronousRequest:urlRequest，因为已弃用

Question

我是Objective-C的入门者，我有一种方法

- (void)getAltitudeFromElevationFromAlt:(float)latitude Long:(float)longitude{
    dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSString *apiKey = @"IzaSyA5CDPUYC7GY5PzJdu_K4ouRy55gm3R5BO4";
        NSString *address = [NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/elevation/json?locations=%f,%f&key=%@", latitude, longitude, apiKey];
        // Send a synchronous request

        NSURLRequest * urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:address]];
        NSURLResponse * response = nil;
        NSError * error = nil;
        NSData * data = [NSURLConnection sendSynchronousRequest:urlRequest
                                              returningResponse:&response
                                                          error:&error];

       NSString *str = @"No Data";
        if (error == nil)
        {
            NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
            str = [NSString stringWithFormat:@"%@", dictionary[@"results"][0][@"elevation"]];
            //  NSLog(@"text  = %@", dictionary[@"results"][0][@"elevation"]);
            NSLog(@"str = %@", str);
            dispatch_async( dispatch_get_main_queue(), ^{
                _altitudeMeterLabel.text = str;
            });
        }
    });
}

请帮助更改此顺序

NSData * data = [NSURLConnection sendSynchronousRequest:urlRequest
                                          returningResponse:&response
                                                      error:&error];

Answer 1

使用NSURLSession和异​​步请求:

- (void)getAltitudeFromElevationFromAlt:(float)latitude Long:(float)longitude {

   NSString *apiKey = @"IzaSyA5CDPUYC7GY5PzJdu_K4ouRy55gm3R5BO4";
   NSString *address = [NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/elevation/json?locations=%f,%f&key=%@", latitude, longitude, apiKey];
   // Send an ASYNCHRONOUS request

   NSURLRequest * urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:address]];
   [[[NSURLSession sharedSession] dataTaskWithRequest:urlRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
      NSString *str = @"No Data";
      if (error) {
         NSLog(@"%@", error);
      } else {
         NSError * jsonError = nil;
         NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&jsonError];
         if (jsonError) {
            NSLog(@"%@", jsonError);
         } else {
            str = [NSString stringWithFormat:@"%@", dictionary[@"results"][0][@"elevation"]];
            //  NSLog(@"text  = %@", dictionary[@"results"][0][@"elevation"]);
            NSLog(@"str = %@", str);
         }
         dispatch_async( dispatch_get_main_queue(), ^{
            _altitudeMeterLabel.text = str;
         });
      }
   }] resume];
}

注意:

由于数据任务始终被调度到后台线程，因此不需要全局dispatch_async块。