iOS-使用MKMapView弹出和推送视图控制器时发生意外崩溃

Question

嗨，有人能帮我解决以下问题吗我有一个ViewController，里面有一个MKMapView，当我弹出这个视图时，一切都很好，但当我试图将这个ViewController推回到NavigationController的堆栈中时，我的应用程序意外崩溃。我试图通过启用NSZombie来解决这个问题，它在从xcode运行时运行良好，但当我尝试在模拟器（和我的iPhone）中运行它而不使用xcode时，它仍然崩溃。我还试图在ViewWillDissapear、ViewDidDissapeal和dealloc中使我的地图视图删除为零，但我仍然有同样的问题。有人能帮我吗？

这是应用程序崩溃时的日志输出：

-[__NSCFType observedViewControllerChange:]：无法识别的选择器发送到实例0x79a6f502012-09-14 11:28:13.878***[456:12503]*由于未捕获异常"NSInvalidArgumentException"而终止应用程序，原因："-[__NSCFType observedViewControllerChange:]：无法识别的选择器发送到实例0x79a6f50'*第一次抛出调用堆栈：（0x19af022 0x179ecd6 0x19b0cbd 0x1915ed0 0x1915cb2 0x12c3a29 0x197a855 0x197a778 0x120819a 0x9d9c97 0xb810 be 0xb813c7 0xb81436 0x931e49 0x931f34 0x1f2c509 0x18e6803 0x18e5d84 0x18e5c9b 0x30967d8 0x09688a 0x901626 0x46ad 0x2d55）terminate调用抛出异常（lldb）

我正在使用arc。下面是一些代码：我在我的viewDidLoad函数中做了很多事情，我认为问题可能就在这里——这是代码：

这是.h:

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <CoreLocation/Corelocation.h>
#import "AddressViewController.h"
#import "Utilities.h"
#import "MarqueeLabel.h"
#import "CustomButton.h"

@interface LocationViewController : UIViewController<MKMapViewDelegate,CLLocationManagerDelegate,UIGestureRecognizerDelegate>{
    CLLocationManager *locationManager;
    MKPointAnnotation *centerAnnotation;
    int initialState;
    NSDictionary * json;
    bool google;
    bool isBackgroundRunning;
    double x;
    CLLocationCoordinate2D selectedCoordinate;
    MarqueeLabel *continuousLabel;
    __weak IBOutlet CustomButton *cont;
    UILongPressGestureRecognizer *lgr;
    UIPanGestureRecognizer *panGesture;
    UIPinchGestureRecognizer *pinchGesture;
    UISwipeGestureRecognizer *swipeGesture;
    __weak IBOutlet UIButton *myLoc;
    BOOL first;
}
@property (strong, nonatomic) IBOutlet MKMapView *myMapView;
- (IBAction)showMe:(id)sender;
@property (strong, nonatomic) MKPointAnnotation *centerAnnotation;
@end


- (void)viewDidLoad
{
    [super viewDidLoad];
    first = YES;
    initialState = YES;
    nrGooglePosts = 0;
    [self.myMapView setShowsUserLocation:YES ];

    myMapView.centerCoordinate = myMapView.userLocation.coordinate;
    locationManager = [[CLLocationManager alloc] init];
    [locationManager setDelegate:self];
    [locationManager setDistanceFilter:kCLDistanceFilterNone];
    [locationManager setDesiredAccuracy:kCLLocationAccuracyBest];

    NSMutableArray *userL =[[NSUserDefaults standardUserDefaults] objectForKey:@"user"];
    if([userL count] == 0) NSLog(@"user nu e salvat");
    [[Utilities get] setName:[[userL valueForKey:@"name"] objectAtIndex:0]];
    [[Utilities get] setPhone:[[userL valueForKey:@"phone"] objectAtIndex:0]];
    [[Utilities get] setCode:[[userL valueForKey:@"code"] objectAtIndex:0]];
    [[Utilities get] setUserId:[[userL valueForKey:@"userid"] objectAtIndex:0]];

    centerAnnotation = [[MKPointAnnotation alloc] init];
    MKPointAnnotation * pc = [[MKPointAnnotation alloc] init];
    pc.coordinate = myMapView.centerCoordinate;
    pc.title = @"Map Center";
    pc.subtitle= [[NSString alloc] initWithFormat:@"%f, %f",pc.coordinate.latitude,pc.coordinate.longitude];    
    [self.myMapView addAnnotation:pc];
    centerAnnotation = pc;
    lgr= [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    lgr.minimumPressDuration=0.1;
    lgr.allowableMovement = 5;
    lgr.delegate = self ;
    [myMapView addGestureRecognizer:lgr];
    panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    panGesture.delegate = self;
    [myMapView addGestureRecognizer:panGesture];
    pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    pinchGesture.delegate = self;
    [myMapView addGestureRecognizer:pinchGesture];
    swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    swipeGesture.delegate = self;
    [myMapView addGestureRecognizer:swipeGesture];

    NSMutableArray * arr=[[NSUserDefaults standardUserDefaults ] objectForKey:@"locationList"];
    if([arr count]){
        for(int i = 0 ; i < [arr count] ; i++ ){
            NSMutableDictionary * adr = [[arr objectAtIndex:i] mutableCopy];
            if(adr){
                CLLocationDegrees lat = [[adr objectForKey:@"latitude"] doubleValue] ;
                CLLocationDegrees lon = [[adr objectForKey:@"longitude"] doubleValue] ;
                CustomMKAnnotation *ann = [[CustomMKAnnotation alloc] init ];
                CLLocationCoordinate2D coord = { lat, lon };
                ann.coordinate = coord;
                ann.title = [adr objectForKey:@"street"] ;   
                ann.subtitle = [[NSString alloc] initWithFormat:@"Nr:%@  Bl:%@  Sc:%@",[adr objectForKey:@"number"],[adr objectForKey:@"bloc"],[adr objectForKey:@"scara"]];
               MKAnnotationView *aux = [[MKAnnotationView alloc] initWithAnnotation:ann reuseIdentifier:nil];  
                UIImage *poza = [UIImage imageNamed:@"star.png"];
                UIImageView *pic = [[UIImageView alloc] initWithImage:poza];
                [aux addSubview:pic];
                aux.canShowCallout = YES;
                [myMapView addAnnotation:aux.annotation];

            }
        }
    }
    google = YES;
    json = [self getLocationFromGoogleWithCoordinates:myMapView.userLocation.coordinate];
    NSString *status = [[NSString alloc] initWithFormat:@"%@",[json objectForKey:@"status"]];
    if([status compare:@"ZERO_RESULTS"] == 0 && [status compare:@"OVER_QUERY_LIMIT"] == 0)
    {
        google=NO;
        NSLog(@"%@",status);
    }
    continuousLabel = [[MarqueeLabel alloc] initWithFrame:CGRectMake(32, 20, 191, 20) rate:50.0f andFadeLength:10.0f];
    continuousLabel.marqueeType = MLContinuous;
    continuousLabel.numberOfLines = 1;
    continuousLabel.opaque = NO;
    continuousLabel.enabled = YES;
    continuousLabel.shadowOffset = CGSizeMake(0.0, -1.0);
    continuousLabel.textAlignment = UITextAlignmentLeft;
    continuousLabel.backgroundColor = [UIColor clearColor];
    continuousLabel.font = [UIFont boldSystemFontOfSize:13];
    continuousLabel.text = [[Utilities get] streetName];
    [continuousLabel setBackgroundColor:[UIColor clearColor]];
    [continuousLabel setTextColor:[UIColor whiteColor]];
    continuousLabel.opaque = NO ;
    myLoc.opaque=NO;
    [myLoc setBackgroundColor:[UIColor clearColor]];
    [self.view addSubview:continuousLabel];

    [logoutButton setTitle:@"Log Out" forState:UIControlStateNormal];
    [logoutButton addTarget:self action:@selector(logout:) forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *logoutBarButton = [[UIBarButtonItem alloc] initWithCustomView:logoutButton]; 
    self.navigationItem.leftBarButtonItem = logoutBarButton;

    [self.navigationController.navigationBar setBackgroundColor:[UIColor clearColor]];

}
- (void) viewWillDisappear:(BOOL)animated
{
    [self.navigationController setNavigationBarHidden:YES animated:animated];
    [self stopTrackingLocation];
    [myMapView removeAnnotations:myMapView.annotations];
      self.myMapView.delegate = nil;
      self.view = nil;
    [super viewWillDisappear:animated];
}

- (void)stopTrackingLocation
{
    if (myMapView.showsUserLocation)
    {
        // Crashes here
        myMapView.showsUserLocation = NO;
    }
}

Answer 1

正如我所看到的，您正在使用ARC.

嘿，伙计，不要这样做：

self.view = NULL. //REMOVE THIS!!!!

您无法再次推送UIViewController，因为没有与之相关的UIVIew。这将导致UINavigationController崩溃，因为实际上没有什么可推送的。

第二个问题，它不造成崩溃，但有一席之地。您正在删除"地图视图"代理。但是，如果您要再次按下此控制器，则第二次时间映射视图将被禁用。

您应该将此功能移到dealloc方法中。您应该在viewWillAppear:方法中显示用户位置，而不是在viewDidLoad:中，因为此方法只执行一次。当您第二次尝试推送UIVIewController时，它将不会生效。因此，请更改此功能：

- (void) viewWillAppear:(BOOL)animated{
     [self.myMapView setShowsUserLocation:YES ];
}
- (void) viewWillDisappear:(BOOL)animated
{
    [self.navigationController setNavigationBarHidden:YES animated:animated];
    [self stopTrackingLocation];
    [myMapView removeAnnotations:myMapView.annotations];
    [super viewWillDisappear:animated];
}
-(void) dealloc{
     self.myMapView.delegate = nil;
     //In ARC we don't call [super dealloc]
}