Objective-C Mapview only works once - ios

Question

I have a problem with my mapview. When I go to the view it works but when I go to another view and go back to the mapview it doesn't work anymore. I get the right latitude and longitude when I NSLog() it, so that is not the problem.
Code:
- (void) viewDidAppear:(BOOL)animated {
if(IS_IPHONE5) {
mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0,300,320,300)];
} else {
mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0,250,320,250)];
}
mapView.mapType = MKMapTypeStandard;
CLLocationCoordinate2D coord = {.latitude = [testLatitude floatValue], .longitude = [testLongitude floatValue]};
MKCoordinateSpan span = {.latitudeDelta = 0.05, .longitudeDelta = 0.05};
MKCoordinateRegion region = {coord, span};
[mapView setRegion:region];
[self.view addSubview:mapView];
CLLocationCoordinate2D annotationCoord;
annotationCoord.latitude = [testLatitude floatValue];
annotationCoord.longitude = [testLongitude floatValue];
MKPointAnnotation *annotationPoint = [[MKPointAnnotation alloc] init];
annotationPoint.coordinate = annotationCoord;
annotationPoint.title = stringTitle;
[mapView addAnnotation:annotationPoint];
}

Answer 1

based on what you've shown you keep adding map views (a new one each time the VC appears)
you seem to have forgotten to remove it!?

Answer 2

why are you allocating your mapview in viewdidAppear? it will add you map view multiple times on the screen if it is not removed on viewdidDisAppear

Answer 3

In your case you are not removing the map view that is already added , what you can do is use
- (void)viewWillAppear Method to Remove the map like that
- (void)viewWillAppear:(BOOL)animated
{
if(map != nil)
{
[map removeFromSuperview];
}
}
it will removed the previous map view before adding the new map

Answer 4

Add this code to your view:
-(void)viewDidDisappear:(BOOL)animated {
if(mapView)
{
[mapView removeFromSuperview];
}
}
}
Also to remove all subviews:
-(void)viewWillAppear:(BOOL)animated {
for (UIView *view in self.subviews) {
[view removeFromSuperview];
}
}

Answer 5

Try like this it may help
- (void) viewDidAppear:(BOOL)animated {
[super viewDidAppear:(BOOL)animated];
if(IS_IPHONE5) {
if (mapView == nil){
mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0,300,320,300)];
[mapview setDelegate:self];
}
} else {
if (mapView == nil){
mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0,250,320,250)];
[mapview setDelegate:self];
}
}
//Add ramaining Code
}
viewDidDisappear Code
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:(BOOL)animated];
[mapView removeFromSuperview];
mapView = nil;
}
ViewDidAppear: if mapview nil we are creating the mapview otherwise not
viewDidDisappear:if we go outside view we are removing the map