xcode - 尝试在 Pin (MKMapView) 上居中 map

Question

正在努力寻找一种方法来使 map 缩放并以注释图钉为中心。 Pin 掉落，但 map 加载海洋。代码如下。

- (void) connectionDidFinishLoading:(NSURLConnection *)connection
{
  [self setString];

  NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:nil];
  NSDictionary *location = [dic objectForKey:@"location"];
  NSDictionary *coordinate = [location objectForKey:@"coordinate"];
  NSString *lat = [coordinate objectForKey:@"latitude"];
  NSString *lon = [coordinate objectForKey:@"longitude"];

  for (NSDictionary *diction in coordinate)
  {
    [array addObject:lat];
    [array addObject:lon];
  }
  {
    CLLocationCoordinate2D track;
    track.latitude = [lat doubleValue];
    track.longitude = [lon doubleValue];

    MapViewAnnotation *newAnnotation = [[MapViewAnnotation alloc] initWithTitle:@"Title of Place Here" andCoordinate:track];

    [self.mapView addAnnotation:newAnnotation];
  }
}

第二个问题，非常相关:

在实现上述问题的答案后，我修改了我的代码。现在，我的坐标从前一个 View 进入我的 MKMapView，这样我就不必费心进行两次 API 调用，第二次是在 MKMapView 中。目前在我的 ViewWillAppear 中，我有以下内容，并且再次遇到 View 无法居中和放大图钉的问题:

if ([self.stringToDisplay isEqualToString: @"Firehouse Gallery"])
{
    UIImage *img = [UIImage imageNamed:@"firehouse.jpg"];
    [imageView setImage:img];

    CLLocationCoordinate2D track;
    track.latitude = [lat doubleValue];
    track.longitude = [lon doubleValue];

    MKCoordinateRegion region;
    MKCoordinateSpan span;
    span.latitudeDelta = 0.01;
    span.longitudeDelta = 0.01;
    region.span = span;
    region.center = track;

    MapViewAnnotation *newAnnotation = [[MapViewAnnotation alloc] initWithTitle:@"Firehouse Gallery" andCoordinate:track];

    [self.mapView addAnnotation:newAnnotation];
    [self.mapView setRegion:region animated:TRUE];
    [self.mapView regionThatFits:region];
}

非常感谢反馈，因为我不知道我还应该做什么。引脚加载到正确的坐标上，只是不居中/缩放...

Answer 1

尝试这个:

{
    CLLocationCoordinate2D track;
    track.latitude = [lat doubleValue];
    track.longitude = [lon doubleValue];

    MKCoordinateRegion region;
    MKCoordinateSpan span;
    span.latitudeDelta = 0.01;
    span.longitudeDelta = 0.01;
    region.span = span;
    region.center = track;

    MapViewAnnotation *newAnnotation = [[MapViewAnnotation alloc] initWithTitle:@"Title of Place Here" andCoordinate:track];

    [self.mapView addAnnotation:newAnnotation];
    [self.mapView setRegion:region animated:TRUE];
    [self.mapView regionThatFits:region];
}