Mapkit :如何在MKLocalSearch结果地标上添加注释？

Question

基本上，我需要一种方法将注释放在搜索请求获得的所有“Walmart”上。我没有使用界面生成器，我只是使用这个应用程序的代码。

MKMapView * map = [[MKMapView alloc] initWithFrame:
                   CGRectMake(0, 0, 320, 480)];
map.delegate = self;
[self.view addSubview:map];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.



MKLocalSearchRequest *request = [[MKLocalSearchRequest alloc] init];
request.naturalLanguageQuery = @"Walmart";
request.region = map.region;

Answer 1

我建议在viewDidLoad中简单地创建mapview

- (void)viewDidLoad
{
    [super viewDidLoad];

    MKMapView * map = [[MKMapView alloc] initWithFrame:self.view.bounds];
    map.delegate = self;

    [self.view addSubview:map];
}

但当用户移动地图时，查找沃尔玛并添加注释：

- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated
{
    // if on slow network, it's useful to keep track of the previous
    // search, and cancel it if it still exists

    [self.previousSearch cancel];

    // create new search request

    MKLocalSearchRequest *request = [[MKLocalSearchRequest alloc] init];
    request.naturalLanguageQuery = @"Walmart";
    request.region = mapView.region;

    // initiate new search

    MKLocalSearch *localSearch = [[MKLocalSearch alloc] initWithRequest:request];
    [localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {

        NSMutableArray *annotations = [NSMutableArray array];

        [response.mapItems enumerateObjectsUsingBlock:^(MKMapItem *item, NSUInteger idx, BOOL *stop) {

            // if we already have an annotation for this MKMapItem,
            // just return because you don't have to add it again

            for (id<MKAnnotation>annotation in mapView.annotations)
            {
                if (annotation.coordinate.latitude == item.placemark.coordinate.latitude &&
                    annotation.coordinate.longitude == item.placemark.coordinate.longitude)
                {
                    return;
                }
            }

            // otherwise, add it to our list of new annotations
            // ideally, I'd suggest a custom annotation or MKPinAnnotation, but I want to keep this example simple

            [annotations addObject:item.placemark];
        }];

        [mapView addAnnotations:annotations];
    }];

    // update our "previous" search, so we can cancel it if necessary

    self.previousSearch = localSearch;
}

显然，此代码示例假定您具有用于前一个搜索操作的weak属性。(严格地说，这并不是必需的，但如果您在Internet连接速度较慢的情况下浏览地图，则可能会获得更好的性能。)无论如何，该属性的定义如下：

@property (nonatomic, weak) MKLocalSearch *previousSearch;

还有其他可能的改进(例如，如果搜索正在进行，则使用UIActivityIndicatorView或网络活动指示器，可能会删除不在地图当前区域内的注释，等等)，但希望您能理解。

Answer 2

以下是方法：

MKLocalSearch *localSearch = [[MKLocalSearch alloc] initWithRequest:request];
[self.localSearch startWithCompletionHandler:^(MKLocalSearchResponse *response, NSError *error) {

if(error)
{
        NSLog(@"localSearch startWithCompletionHandlerFailed!  Error: %@", error);
        return;
} 
else 
{
        for(MKMapItem *mapItem in response.mapItems)
        {
             MKPinAnnotation *annotation = [[MKPinAnnotation alloc] initWithCoordinate: mapItem.placemark.location.coordinate];
             [map addAnnotation:annotation];
             NSLog(@"Name for result: = %@", mapItem.name);
        }
}}];