[NSURL initFileURLWithPath:]: nil string parameter when trying to load a view

Question

When my view is trying to load, the applications crashes and i get this stack:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter'

This is my code, i don't really know where to look when this crash is occurred:

#import "Itineraire.h"
#import "SBMapView.h"
#import "SBRouteAnnotation.h"
#import "City.h"
#import "UICGRoutes.h"
#import "SBCheckPointViewController.h"
//#import "SBRouteDetailView.h"

@interface Itineraire(Private)
-(void)customInitialization;
@end

@implementation Itineraire(Private)

-(void)customInitialization
{
    // do the initialization of class variables here..

    mDirections          = [UICGDirections sharedDirections];
    mDirections.delegate = self;
}

@end

@implementation Itineraire

@synthesize map             = mMap;
@synthesize startPoint      = mStartPoint;
@synthesize endPoint        = mEndPoint;
@synthesize loadBtn     = mLoadBtn;
@synthesize annotationArray = mAnnotationArray;
@synthesize travelMode      = mTravelMode;
@synthesize destination;
@synthesize routes;
@synthesize mAnnotations;
@synthesize mRouteArray;
@synthesize mRouteDetail;

//Invoked when the class is instantiated in XIB
-(id)initWithCoder:(NSCoder*)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if( self)
    {
        [self customInitialization];
    }
    return self;
}

// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
        [self customInitialization];
    }
    return self;
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"Google Maps";
    self.map = [[SBMapView alloc] initWithFrame:CGRectMake(0, 49, self.view.frame.size.width, self.view.frame.size.height)];
    //self.map = [[SBMapView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 381)];

    [self.view addSubview:mMap];

    self.view.backgroundColor = [UIColor blackColor];
    self.annotationArray = [[NSMutableArray alloc]init];
    self.routes          = [[UICGRoutes alloc]init];


    if (mDirections.isInitialized) {
        [self updateRoute];
    }
}
/*
 // Override to allow orientations other than the default portrait orientation.
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
 // Return YES for supported orientations
 return (interfaceOrientation == UIInterfaceOrientationPortrait);
 }
 */

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];

}
- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:YES];

}
- (void)viewWillDisappear:(BOOL)animated; 
{
    [super viewWillDisappear:YES];

}

#pragma mark -
#pragma mark Instance Methods

- (void)updateRoute
{   /*
     [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
     UICGDirectionsOptions *options = [[[UICGDirectionsOptions alloc] init] autorelease];
     options.travelMode = mTravelMode;
     City *mFirstCity = [[[City alloc]init] autorelease];
     mFirstCity.mCityName = @"Paris";//mStartPoint;
     //[mDirections loadWithStartPoint:mFirstCity.mCityName endPoint:destination options:options];
     //added
     NSMutableArray * DestinationCityArray = [[NSMutableArray alloc]init];
     [DestinationCityArray addObject:@"Berlin"];
     [mDirections loadWithStartPoint:mFirstCity.mCityName endPoint:destination options:options];
     */
    //
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
    UICGDirectionsOptions *options = [[UICGDirectionsOptions alloc] init] ;
    options.travelMode = mTravelMode;
    City *mFirstCity = [[City alloc]init];
    mFirstCity.mCityName = @"Amsterdam";//mStartPoint;
    NSMutableArray *dest=[[NSMutableArray alloc]init];
    [dest addObject:@"Berlin"];
    [mDirections loadWithStartPoint:mFirstCity.mCityName endPoint:dest options:options];


}

-(void)loadRouteAnnotations
{
    self.mRouteArray = [mDirections routeArray];
    NSLog(@"mRouteArray %@",mRouteArray);
    self.mAnnotations = [[NSMutableArray alloc]init];
    for (int idx = 0; idx < [mRouteArray count]; idx++) {
        NSArray *_routeWayPoints1 = [[mRouteArray objectAtIndex:idx] wayPoints];
        NSArray *mPlacetitles = [[mRouteArray objectAtIndex:idx] mPlaceTitle]; 
        self.annotationArray = [NSMutableArray arrayWithCapacity:[_routeWayPoints1 count]-2];

        mLoadBtn.title = @"OFF";
        mLoadBtn.target = self;
        mLoadBtn.action = @selector(removeRouteAnnotations);

        for(int idx = 0; idx < [_routeWayPoints1 count]-1; idx++)
        {

            mBetweenAnnotation = [[SBRouteAnnotation alloc] initWithCoordinate:[[_routeWayPoints1 objectAtIndex:idx]coordinate]
                                                                          title:[mPlacetitles objectAtIndex:idx]
                                                                 annotationType:SBRouteAnnotationTypeWayPoint];
            [self.annotationArray addObject:mBetweenAnnotation];
        }
        [mAnnotations addObject:mAnnotationArray];
        [self.map.mapView addAnnotations:[mAnnotations objectAtIndex:idx]];
        NSLog(@"map %@",mMap);

    }   
}

-(void)showCheckpoints
{
    SBCheckPointViewController *_Controller = [[SBCheckPointViewController alloc]initWithNibName:@"SBCheckPoints" bundle:nil];
    [self.navigationController pushViewController:_Controller animated:YES];
    NSMutableArray *arr = [[mDirections checkPoint] mPlaceTitle];
    _Controller.mCheckPoints = arr ;


}



//
-(void)removeRouteAnnotations
{
    NSMutableArray *mTempAnnotation;// = [mAnnotations retain];
    for (int idx = 0; idx < [mTempAnnotation count]; idx++) {
        [mMap.mapView removeAnnotations:[mTempAnnotation objectAtIndex:idx] ];
    }   
    mLoadBtn.title = @"ON";
    mLoadBtn.target = self;
    mLoadBtn.action = @selector(loadRouteAnnotations);
}


#pragma mark <UICGDirectionsDelegate> Methods

- (void)directionsDidFinishInitialize:(UICGDirections *)directions {
    [self updateRoute];
}

- (void)directions:(UICGDirections *)directions didFailInitializeWithError:(NSError *)error {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Map Directions" message:[error localizedFailureReason] delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
    [alertView show];
}

- (void)directionsDidUpdateDirections:(UICGDirections *)indirections {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];

    UICGPolyline *polyline = [indirections polyline];
    NSArray *routePoints = [polyline routePoints];

    [mMap loadRoutes:routePoints]; // Loads route by getting the array of all coordinates in the route.

    UIToolbar *tools = [[UIToolbar alloc]
                        initWithFrame:CGRectMake(0.0f, 0.0f, 103.0f, 44.01f)]; // 44.01 shifts it up 1px for some reason
    tools.clearsContextBeforeDrawing = NO;
    tools.clipsToBounds = NO;
    tools.tintColor = [UIColor colorWithWhite:0.305f alpha:0.0f]; // closest I could get by eye to black, translucent style.
    // anyone know how to get it perfect?
    tools.barStyle = -1; // clear background
    NSMutableArray *buttons = [[NSMutableArray alloc] initWithCapacity:2];

    // Create a standard Load button.

    self.loadBtn = [[UIBarButtonItem alloc]initWithTitle:@"ON" 
                                                   style:UIBarButtonItemStyleBordered 
                                                  target:self 
                                                  action:@selector(loadRouteAnnotations)];

    [buttons addObject:mLoadBtn];

    // Add Go button.
    UIBarButtonItem *mGoBtn = [[UIBarButtonItem alloc] initWithTitle:@"Go" 
                                                               style:UIBarButtonItemStyleBordered 
                                                              target:self 
                                                              action:@selector(showCheckpoints)];
    [buttons addObject:mGoBtn];

    // Add buttons to toolbar and toolbar to nav bar.
    [tools setItems:buttons animated:NO];
    UIBarButtonItem *twoButtons = [[UIBarButtonItem alloc] initWithCustomView:tools];
    self.navigationItem.rightBarButtonItem = twoButtons;

    //Add annotations of different colors based on initial and final places.
    SBRouteAnnotation *startAnnotation = [[SBRouteAnnotation alloc] initWithCoordinate:[[routePoints objectAtIndex:0] coordinate]
                                                                                  title:mStartPoint
                                                                         annotationType:SBRouteAnnotationTypeStart];
    SBRouteAnnotation *endAnnotation = [[SBRouteAnnotation alloc] initWithCoordinate:[[routePoints lastObject] coordinate]
                                                                                title:mEndPoint
                                                                       annotationType:SBRouteAnnotationTypeEnd];


    [mMap.mapView addAnnotations:[NSArray arrayWithObjects:startAnnotation, endAnnotation,nil]];
}

- (void)directions:(UICGDirections *)directions didFailWithMessage:(NSString *)message {
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Map Directions" message:message delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
    [alertView show];
}

#pragma mark -

@end

I tried to put my code on a new project (empty application) and it worked fine, i didn't understand that error and its possible causes.

EDIT:

I tried to track the problem by elimination,and my code worked fine when i remove this method:

//Invoked when the class is instantiated in XIB

-(id)initWithCoder:(NSCoder*)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if( self)
    {
        [self customInitialization];
    }
    return self;
}

However, when i run, my app doesn't display me the route between the two points (The purpose of the app). So this method seems important for the whole class because without it, i couldn't get the route and in the other side when it's there, the app crashes. How should i deal with this contradiction?

Answer 1

@Vince is putting you on the right track. Since the problem is in an NSURL method being called by a framework (Google Maps in this case) you need to debug what you are passing to the framework. You have the source for the framework also right? You can set breakpoints in loadWithStartPoint:endPoint:options:] to see what's going on.

One thing I did notice is you are passing an NSMutableArray as the endPoint param when I believe it expects an NSString.