Question

目前我可以在地图上放置别针。现在我希望注释标题显示引脚掉落的位置。

我已经看过这个但是不能让我工作：
Set annotation's title as current address

我的ViewController.m中的代码

更新

- (void)addPinToMap:(UIGestureRecognizer *)gestureRecognizer
{
    if (gestureRecognizer.state != UIGestureRecognizerStateBegan)
        return;

    CGPoint touchPoint = [gestureRecognizer locationInView:self.map];
    CLLocationCoordinate2D touchMapCoordinate =
    [self.map convertPoint:touchPoint toCoordinateFromView:self.map];

    CLLocation *currentLocation = [[CLLocation alloc]
                                   initWithLatitude:touchMapCoordinate.latitude
                                   longitude:touchMapCoordinate.longitude];

    [self.geocoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray *placemark, NSError *error) {

        //initialize the title to "unknown" in case geocode has failed...
        NSString *annTitle = @"Address unknown";

        //set the title if we got any placemarks...
        if (placemark.count > 0)
        {
            CLPlacemark *topResult = [placemark objectAtIndex:0];
            annTitle = [NSString stringWithFormat:@"%@ %@ %@ %@", topResult.country, topResult.locality, topResult.subLocality, topResult.thoroughfare];
        }

        //now create the annotation...
        MapAnnotation *toAdd = [[MapAnnotation alloc]init];

        toAdd.coordinate = touchMapCoordinate;
        toAdd.title = annTitle;
        //toAdd.title = @"Title";
        toAdd.subtitle = @"Subtitle";

        [self.map addAnnotation:toAdd];
    }];
}

Answer 1

首先，在addPinToMap:方法中，使用addressLocation调用currentLocation，但永远不会设置currentLocation。它被声明了几行但没有设置为任何值。

所以改变：

CLLocation *currentLocation;

为：

CLLocation *currentLocation = [[CLLocation alloc] 
                                initWithLatitude:touchMapCoordinate.latitude 
                                longitude:touchMapCoordinate.longitude];

第二，即使使用此修复程序，它仍然无法正常工作。注释的title将不会被设置，因为reverseGeocodeLocation方法的完成处理程序块将在添加注释后完成（块是异步的 - addPinToMap:中的代码不会等待它完成了。）

当您实际拥有地理编码器结果（无论是成功还是失败）时，您需要稍微更改代码并在完成块中添加注释。

将reverseGeocodeLocation调用移至addPinToMap:方法：

CLLocation *currentLocation = [[CLLocation alloc] initWithLatitude:touchMapCoordinate.latitude longitude:touchMapCoordinate.longitude]; [self.geocoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray *placemark, NSError *error) { //initialize the title to "unknown" in case geocode has failed... NSString *annTitle = @"Address unknown"; //set the title if we got any placemarks... if (placemark.count > 0) { CLPlacemark *topResult = [placemark objectAtIndex:0]; annTitle = [NSString stringWithFormat:@"%@ %@ %@ %@", topResult.country, topResult.locality, topResult.subLocality, topResult.thoroughfare]; } //now create the annotation... MapAnnotation *toAdd = [[MapAnnotation alloc]init]; toAdd.coordinate = touchMapCoordinate; toAdd.title = annTitle; toAdd.subtitle = @"Subtitle"; [self.map addAnnotation:toAdd]; }];

在地图上放置引脚时显示注释中的地址

1 个答案: