想要每隔5秒在MKMapView中显示针脚点

Question

我有三个地点。我想在每5秒内随机逐一显示它们。

我使用过这段代码：

-(IBAction)onMap:(id)sender
{
    [NSTimer scheduledTimerWithTimeInterval:10.0
                                     target:self
                                   selector:@selector(loadMap)
                                   userInfo:nil
                                    repeats:YES];
}

-(void)loadMap
{
    [mapView1 removeAnnotations:mapView1.annotations];

    int i = random()%3;

    location.latitude = [[lat_Array objectAtIndex:i] doubleValue];
    location.longitude =[[long_Array objectAtIndex:i] doubleValue];

    CLLocationCoordinate2D center = coordinate;
    [mapView1 setCenterCoordinate:center];

    NSMutableArray *marketLocations =[[NSMutableArray alloc]init];

    MapAnnotation *addAnnotation = [[MapAnnotation alloc] initWithCoordinate:location];

    [addAnnotation setTitle:@"name"];

    [marketLocations addObject:addAnnotation];

    [mapView1 addAnnotations:marketLocations];

    // region.center = location;

    span.latitudeDelta = 150.0f;
    span.longitudeDelta = 150.0f;

    region.span=span;

    [mapView1 setRegion:region animated:FALSE];
    [mapView1 regionThatFits:region];
}

#pragma mark - Mapview delegate
- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"MyPin"];

    annView.animatesDrop=FALSE;
    annView.canShowCallout = YES;
    annView.pinColor = MKPinAnnotationColorPurple;

    //annView.rightCalloutAccessoryView = rightButton;

    return annView;
}

它正确显示位置，但在每次加载时，它会从用户的滚动中聚焦到非洲。

我不希望这样。我只想留在用户滚动到的位置。