使用MKMapView时出现问题，我的标注点没有正确显示方向（我正在使用MKMapView的罗盘模式）。

Question

我正在开发一款与地图相关的iPhone应用程序。在这个应用程序中，我需要根据停车场的纬度和经度显示一些停车场位置（地址）。目前为止，我已经成功完成了这一点，但是我想根据用户的方向（SE，SW，NE，NW）显示Pin Points。我尝试使用MKMapview中的罗盘模式，但它显示的Pin Points方向是错误的。

我的代码有错误还是Web服务有问题？我将用户位置LAT和LONG以及用户方向传递给Web服务。

现在我向您展示屏幕截图。

- (void)updateHeading:(CLHeading *) newHeading {
NSLog(@"New magnetic heading: %f", newHeading.magneticHeading);
NSLog(@"New true heading: %f", newHeading.trueHeading);
double rotation = newHeading.magneticHeading * 3.14159 / 180;
NSLog(@"rotation ========> %f",rotation);
[mapView setTransform:CGAffineTransformMakeRotation(rotation)];

[[mapView annotations] enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    MKAnnotationView * view = [mapView viewForAnnotation:obj];

    [view setTransform:CGAffineTransformMakeRotation(rotation)];
}];
//NSLog(@"newlocation course : %f",mapView.userLocation.location.course);
float mHeading = newHeading.magneticHeading;
NSLog(@"mHeading %f",mHeading);
//direction is a string
if(mHeading > 0 && mHeading <90) {
    // north east
    NSLog(@"~~~~~~~~~~~~~~~~north east");
    direction = @"North East";
}
else if(mHeading > 90 && mHeading < 180)  {
    // south east
    NSLog(@"~~~~~~~~~~~~~~~~south east");
    direction = @"South East";
}
else if(mHeading > 180 && mHeading < 270) {
    // south west
    NSLog(@"~~~~~~~~~~~~~~~~south west");
    direction = @"South West";
}
else if(mHeading > 270 && mHeading < 360) {
    // north west
    NSLog(@"~~~~~~~~~~~~~~~~north west");
    direction = @"North West";
}

if([changedDirction isEqualToString:direction])
{
    NSLog(@"called nothing/changedDirction.....");
}
else
{
  NSURL *url = [NSURL URLWithString:@"http://www.charlottecentercity.org/services/nearbylocations.php"];
  NSLog(@"url is---%@",url);
  directionsRequest = [[ASIFormDataRequest alloc] initWithURL:url];
 [directionsRequest setPostValue:[NSString stringWithFormat:@"%f", appdelegate.currentLocation.latitude] forKey:@"lat"];
 [directionsRequest setPostValue:[NSString stringWithFormat:@"%f", appdelegate.currentLocation.longitude] forKey:@"long"];
 directionLabel.text = direction;
[directionsRequest setPostValue:direction forKey:@"direction"];
[directionsRequest setPostValue:self.mapID forKey:@"id"];
 directionsRequest.delegate = self;
[directionsRequest startAsynchronous];
 changedDirction = direction;
 } }


-(void)requestFinished:(ASIHTTPRequest *)request {
NSLog(@"request finished is calling....");
if ([venuDescArray count]>0)
{
    [venuDescArray removeAllObjects]; 

}

NSError *error = [request error];
NSLog(@"error is%@",error);
if (!error) 
{
    NSString *responseString = [request responseString];
    NSMutableArray *array = [responseString JSONValue];
    NSLog(@"response array for category wise pin--%@",array);
    for (int i = 0; i<[array count]; i++) 
    {
        NSMutableDictionary *theDict = [array objectAtIndex:i];
        PlacesObject *aVenue = [[PlacesObject alloc] init];
        aVenue.venueDetailsplaceID = [theDict objectForKey:@"placeid"];
        aVenue.venueDetailsname = [theDict objectForKey:@"name"];
        aVenue.venueDetailsaddress = [theDict objectForKey:@"address"];
        aVenue.venueDetailslatitude = [theDict objectForKey:@"latitude"];
        aVenue.venueDetailslongitude = [theDict objectForKey:@"longitude"];

        [venuDescArray addObject:aVenue];
    }

    NSLog(@"venuDescArray count is---%d",[venuDescArray count]);
}
[self setLocations]; }

-(void)setLocations {

[annotaionsArray11 removeAllObjects];
[mapView removeAnnotations:mapView.annotations];
 NSLog(@"annotations removed....");

self.mapView.mapType = MKMapTypeStandard;
self.mapView.delegate = self;

MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];

float lati_new =appdelegate.currentLocation.latitude;//35.227087;
float longi_new =appdelegate.currentLocation.longitude;//-80.843127; 

myAnnotation.annType=@"Current";
myAnnotation.title1 =@"Current our Location";

myAnnotation.latitude=[NSNumber numberWithFloat:lati_new];
myAnnotation.longitude =[NSNumber numberWithFloat:longi_new];
NSLog(@"myAnnotation.latitude/float---%@",myAnnotation.latitude);
NSLog(@"myAnnotation.longitude/float---%@",myAnnotation.longitude);

[annotaionsArray11 addObject:myAnnotation];

[myAnnotation setButtonTag:0];

 NSLog(@"self.venuDescArray count:%d",[self.venuDescArray count]);

PlacesObject *placesObj=[[PlacesObject alloc] init];

for (int i=0; i<[self.venuDescArray count]; i++) 
{
    placesObj=[self.venuDescArray objectAtIndex:i];

    MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];

    myAnnotation.annType=@"Points";

    myAnnotation.title1 =placesObj.venueDetailsname;
    NSLog(@"myAnnotation.title1's is---%@",myAnnotation.title1);
    myAnnotation.subTitle =placesObj.venueDetailsaddress;
    NSLog(@"myAnnotation.subTitle is---%@",myAnnotation.subTitle);
    myAnnotation.latitude =[NSNumber numberWithFloat:[placesObj.venueDetailslatitude floatValue]];
    NSLog(@"myAnnotation.latitudes is ----%@",myAnnotation.latitude);
    myAnnotation.longitude =[NSNumber numberWithFloat:[placesObj.venueDetailslongitude floatValue]];
    NSLog(@"myAnnotation.longitude is ----%@",myAnnotation.longitude);
    [annotaionsArray11 addObject:myAnnotation];
    NSLog(@"annotaionsArray11---%d",[annotaionsArray11 count]);

    [myAnnotation setButtonTag:i];
}

NSLog(@"annotaionsArray count after adding all locations..%d",[annotaionsArray11 count]);
 [mapView addAnnotations:annotaionsArray11];  }

感谢您提前提供的任何帮助。 @harikrishna

- Hari1251

---

“正确方向”是指您希望针头始终指向北方，即使地图旋转以致西边在屏幕顶部吗？如果是这样，我建议不要这样做。我在其他任何地图应用程序中都没有看到过这样的操作，您的用户可能会认为针已经全部倒下非常奇怪。 - Craig

你确定你从网络服务获取到了正确的响应吗？ - nhisyam

Answer 1

由于这个问题有些具体，而且并没有展示所有的代码，我只能从当前可用的信息中尝试推断。

您想根据用户的方向显示四个不同组的停车位置，但是当改变方向时，注释并没有改变。

基于网络服务返回正确结果的假设，问题可能是由您使用的方式引起的。

MKAnnotationView * view = [mapView viewForAnnotation:obj];

请检查您的代码中是否使用了reuseIdentifier。

- Zhenshan Yu