I can't add more than 1 annotation to MKMapview :|

Question

So I'm pulling my hair out over this one. I've been tracking down a bug in my app. Originally, I was trying to load long / lat coordinates from a database and do a for loop, adding each annotation to the map view. This seemed simple enough, but for some reason when I tried to add the annotations in the loop it would only show 1 annotation in the end.

So, using the code below, I decided to try and simply add two annotations to MKMapView to be sure that I can do this in the first place, and it doesn't work!

[NewAnnotation setLongitude:-104.6200448];
[NewAnnotation setLongitude:50.4908343];
NewAnnotation *newAnnotation = [[NewAnnotation alloc] init];
[self.mapAnnotations insertObject:newAnnotation atIndex:0];
[newAnnotation release];

[CelebsAnnotation setLongitude:-90.6200448];
[CelebsAnnotation setLatitude:51.4908343];
CelebsAnnotation *celebsAnnotation = [[CelebsAnnotation alloc] init];
[self.mapAnnotations insertObject:celebsAnnotation atIndex:1];
[celebsAnnotation release];

[self.mapView addAnnotations:mapAnnotations];

The annotations show up in their correct locations if I only add one of them to the mapAnnotations array (I have to adjust the index to 0 if I only add the CelebsAnnotation), but when I try to add both, they show up in the same location on the map?? Any ideas as to why this would happen. I am so confused and frustrated..

Answer 1

Your problem is here,

- (CLLocationCoordinate2D)coordinate; { 
    CLLocationCoordinate2D theCoordinate; 
    theCoordinate.latitude = Clatitude; 
    theCoordinate.longitude = Clongitude; 
    return theCoordinate; 
} 

You are creating a new CLLocationCoordinate2D every time coordinate is requested an you are setting this to the static variables Clongitude & Clatitude . Since these are static variables, you will be returning similar CLLocationCoordinate2D objects for all instances of CelebsAnnotation . So basically all instances will have the same coordinate.

You should rather have an init.. method that takes in a CLLocationCoordinate2D object and set it to an instance variable. For example, look at this tutorial .

You will end up doing something like this,

CLLocationCoordinate2D coordinate;
coordinate.longitude = -90.6200448;
coordinate.latitude = 51.4908343;
CelebsAnnotation *celebsAnnotation = [[CelebsAnnotation alloc] initWithCoordinate:coordinate];
[self.mapAnnotations insertObject:celebsAnnotation atIndex:1];
[celebsAnnotation release];

Answer 2

Here, this code fetching value of lattitude and longitude from database and, placing annotation in map:

            while (sqlite3_step(statement)==SQLITE_ROW)
            {
                char *iTtl=(char *) sqlite3_column_text(statement, 1);
                trackedImageTitle=[NSString stringWithUTF8String:iTtl];
                char *iLat=(char *) sqlite3_column_text(statement, 2);
                trackedLocationLattitude=[NSString stringWithUTF8String:iLat];
                //NSLog(@"lat=%@",trackedLocationLattitude);
                char *iLon=(char *) sqlite3_column_text(statement, 3);
                trackedLocationLongitude=[NSString stringWithUTF8String:iLon];
                //NSLog(@"lon=%@",trackedLocationLongitude);    
                char *lcn=(char *) sqlite3_column_text(statement, 4);
                trackedLocation=[NSString stringWithUTF8String:lcn];    
                int iId=sqlite3_column_int(statement, 0);
                NSString *iIdS =[NSString stringWithFormat:@"%d", iId];
                [allImageIds addObject:[NSString stringWithFormat:@"%@",iIdS]];
                //theImage=iId;
                //NSLog(@"the image=%d, iId= %d",theImage,iId); 
                location.latitude=[trackedLocationLattitude floatValue];
                location.longitude=[trackedLocationLongitude floatValue];   
                addAnnotation = [[MapViewAnnotation alloc] initWithLocation:location withTitle:[NSString stringWithFormat:@"Tuscany"] withSubTitle:[NSString stringWithFormat:@"Italy"] withImage:[UIImage imageNamed:[NSString stringWithFormat:@"%d.jpg",iId]]];
                addAnnotation.mTitle=[NSString stringWithFormat:@"%@",trackedImageTitle];
                addAnnotation.mSubTitle=[NSString stringWithFormat:@"%@",trackedLocation];
                ////NSLog(@"%@",addAnnotation.mTitle);
                [mapView addAnnotation:addAnnotation];
            }

mapView is instance of MKMapView .