Accessing NSDictionary of another ViewController shows null - ios

Question

I am using NSDictionary to plot various markers on a Map.After the pins have been plotted I click the call out of the marker to show the user details.Now when I press the call out I am passing details like marker.title and marker.snippet to another View Controller.With refrence to these values I am trying to fetch other details from the dictionary.This is what I do for accessing the dictionary from another view controller.
-(void)fetchMarkerData:(NSString *)typeOfMarker nameOfUser:(NSString *)username
{
NSString *type = typeOfMarker;
NSString *name = username;
NSLog(#"User Type - %# & Name - %# ", type, name); // shows name and type
NSLog(#"members dict from map view - %#" , self.membersDetailsDict); // shows null & self.membersDetailsDict is allocated and initialised in viewDidLoad.
if ([type isEqualToString:#"Member"])
{
for (NSDictionary *instance in self.membersDetailsDict)
{
NSString *name= [instance objectForKey:#"pseudo"];
if ([name isEqualToString:name])
{
self.nameLabel.text = name;
self.displayPicture.image =[instance objectForKey:#"avatar"];
self.cityLabel.text = [instance objectForKey:#"pays"];
}
}
}
}
Passing data this way :-
- (void)mapView:(GMSMapView *)mapView didTapInfoWindowOfMarker:(GMSMarker *)marker
{
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:#"MainStoryboard"
bundle: nil];
UserProfileViewController *userProfileViewController = (UserProfileViewController *)[mainStoryboard instantiateViewControllerWithIdentifier:#"UserProfileViewController"];
[userProfileViewController fetchMarkerData:marker.snippet nameOfUser:marker.title];
userProfileViewController.membersDetailsDict = self.membersDict; //passing dictionary also
UINavigationController *nv = [[UINavigationController alloc]initWithRootViewController:userProfileViewController];
[self.revealSideViewController popViewControllerWithNewCenterController:nv animated:YES];

Answer 1

It seems as though you are trying to access the membersDict variable from your second view controller which you actually instantiated again there when instead you should be accessing the actual membersDict variable from where it was originally created - in what i assume was in your ViewController1. Now from what I understand this is your setup.
Viewcontroller1 contains your maps data points stored in a variable called membersDict.
user clicks on a point and it will push a viewController2, and that's where you're trying to access the membersDict variable from viewController1.
One way you can do this is by feeding your ViewController2 with the variable from ViewController1 when youre about to push it rather than trying to access the membersDict from your `ViewController2 after its been pushed.
So you can do something like this, this is just a crude quick example:
// in .h viewController file
NSMutabledictionary *membersDict; //whatever the data object was that you stored the data in
//in .m viewController1 file
//viewDidLoad method
membersDict = [[NSMutableDictionary alloc] init];
//add whatever data you like to your membersDict
//In section of code where youre about to push your second ViewController 2: Pass the members dict data too along with pushing the second viewController.
ViewController2 = [[ViewController2 alloc] initWithWhatever];
viewController2.membersDict = self.membersDict; //
or
ViewController2 = [[ViewController2 alloc] initWithMembersDict:self.membersDict];
//Then push the viewController2.
This will ensure your membersDict data successfully passes on.