ios - iPhone - 需要一些关于 EXC_BAD_ACCESS 的帮助，这让我发疯(包括完整的源代码)

Question

我有一个使用 GoogleMap View 的应用。
在该应用程序中，我想显示一些自定义注释和 userLocation 的自定义 View 。当位置管理器给出一个标题时，我想显示 userLocation 的自定义 View ，如果它无法提供一个，我希望默认的蓝色动画点回来，等等......

项目和源代码可用 HERE

嗯，这里有两个问题:

第一个问题，非常糟糕。您可以使用这个小应用程序玩几个小时。但是......启动它，等待它加载，将它发送到后台，将你的 iPhone 置于 sleep 模式，等一下，唤醒你的 iPhone，启动应用程序(唤醒它):崩溃，EXC_BAD_ACCESS。做同样的事情，不要让 iPhone 进入休眠模式:不会崩溃。不是等待一分钟而是几秒钟，没有崩溃。 10 秒，没有崩溃，20 秒，没有崩溃，将近 30 秒，可能会崩溃，将近一分钟，崩溃!

第二个问题(奖励 :-))， 可以与第一个问题联系起来，但这并不是这个问题的真正核心:我用来实现 userPinLocation 更新的解决方案/to the blue pin 似乎有一个非常糟糕的副作用:当你在街上移动时，userLocation 不会在 map 上移动。对于第二个问题的任何答案，如果它与崩溃没有直接关系，请使用评论而不是答案。这不是问题的核心……我认为……

为了找到错误代码，我已将我的应用程序缩减到最低限度。这给出了以下代码(源代码中的一些提示作为注释):

EXC_BAD_ACCESS_TestViewController.h

#import <MapKit/MapKit.h>

@interface EXC_BAD_ACCESS_TestViewController : UIViewController<CLLocationManagerDelegate> {

    CLLocationManager* locationMgr;
    NSMutableArray* customAnnotations;
    CLLocationDirection userHeading;
    MKMapView* myMapView;
}

@property(nonatomic, retain) CLLocationManager* locationMgr;
@property(nonatomic, retain) NSMutableArray* customAnnotations;
@property(nonatomic, assign) CLLocationDirection userHeading;
@property(nonatomic, retain) IBOutlet MKMapView* myMapView;

- (void) loadAnnotations;

@end

EXC_BAD_ACCESS_TestViewController.m

// On first launch, due to code simplification, the app may crash when asked authorization to use geo hardware. Just kill/relaunch after accepting.
// Breakpoints on each method entry : EXC_BAD_ACCESS crash without any break-stop

#import "EXC_BAD_ACCESS_TestViewController.h"
#import "CustomAnnotation.h"

@implementation EXC_BAD_ACCESS_TestViewController

@synthesize locationMgr, customAnnotations, myMapView, userHeading;

// ===========================================================================================================
-(id) initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (!self) return nil;

    self.userHeading = -1;

    return self;
}

// ===========================================================================================================
- (void) viewDidLoad
{
    [self loadAnnotations];

    self.myMapView.mapType = MKMapTypeStandard;
    self.myMapView.showsUserLocation = YES;

    // -----------------------------------------------
    // Just comment this sole line : no more crash
    // -----------------------------------------------
    for (CustomAnnotation* pin in self.customAnnotations) [self.myMapView addAnnotation:pin];

    // locationManager
    self.locationMgr = [[CLLocationManager alloc] init];
    self.locationMgr.desiredAccuracy = kCLLocationAccuracyBest;
    self.locationMgr.distanceFilter = 1.0;
    self.locationMgr.headingFilter = 1.0;
    self.locationMgr.purpose = @"Some purpose.";
    self.locationMgr.delegate = self;
    [self.locationMgr startUpdatingHeading];

    [super viewDidLoad];
}

// ===========================================================================================================
- (void) loadAnnotations
{   
    // Code for testing, real code gets the datas using another way of doing, as simple as this one
    self.customAnnotations = [NSMutableArray array];
    double latitude = 45.0;
    double longitude = -45.0;

    for (int i=1; i<=400; i++) {
        CLLocationCoordinate2D pinLocation = CLLocationCoordinate2DMake(latitude, longitude);
        CustomAnnotation* pin = [[[CustomAnnotation alloc] initWithCoordinate:pinLocation] autorelease];            
        [self.customAnnotations addObject:pin];

        latitude += 0.01;
        longitude += 0.01;
    }
}

// ===========================================================================================================
- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
    MKAnnotationView* pinView = nil;
    NSString* annotationIdentifier;
    UIImage* pinImage;
    BOOL canShowCallout;

    // User location
    if ([annotation isKindOfClass:[MKUserLocation class]] && self.userHeading >= 0) {
        annotationIdentifier = @"UserLocationAnnotation";
        pinImage = [UIImage imageNamed:@"custom_userlocation.png"];
        canShowCallout = NO;
    }
    // Custom Pin
    else if ([annotation isKindOfClass:[CustomAnnotation class]]) {
        annotationIdentifier = @"CustomAnnotation";
        pinImage = [UIImage imageNamed:@"custom_pin.png"];
        canShowCallout = YES;
    }
    // Others
    else {
        return nil;
    }

    pinView = (MKAnnotationView*)[mapView dequeueReusableAnnotationViewWithIdentifier:annotationIdentifier];

    if (pinView) {
        pinView.annotation = annotation;
    }
    else {
        pinView = [[[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:annotationIdentifier] autorelease];
        if (pinView) {
            pinView.image = pinImage;
            pinView.canShowCallout = canShowCallout;

            if (canShowCallout) {
                pinView.calloutOffset = CGPointMake(-5, 5);
                pinView.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            }
        }
    }

    return pinView;
}

// -----------------------------------------------
// Just comment this method : no more crash
// -----------------------------------------------
// ===========================================================================================================
- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading
{
    if (!self.myMapView) return;
    if (!self.myMapView.userLocation) return;

    CLLocationDirection compassHeading_True = newHeading.trueHeading;
    CLLocationDirection compassHeading_Magnetic = newHeading.magneticHeading;

    CLLocationDirection heading;
    if (compassHeading_True == -1)              heading = compassHeading_Magnetic;
    else if (newHeading.headingAccuracy >= 0)   heading = compassHeading_True;
    else                                        heading = -1;

    // If we get/loose the heading, update pin image
    // I didn't found any other solution to force the user pin to update its display.
    if ((self.userHeading == -1 || heading == -1) && self.userHeading != heading) {
        [self.myMapView removeAnnotation:self.myMapView.userLocation];
        self.userHeading = heading;
        [self.myMapView addAnnotation:self.myMapView.userLocation];
    }

    self.userHeading = heading;

    // ------------------------------------
    // Some non bugued code was there
    // ------------------------------------
}

// ===========================================================================================================
- (void) dealloc
{   
    self.myMapView = nil;
    self.customAnnotations = nil;
    self.locationMgr = nil;

    [super dealloc];
}

@end

自定义注释.h

#import <MapKit/MapKit.h>

@interface CustomAnnotation : NSObject<MKAnnotation> {
    CLLocationCoordinate2D coordinate;
}

@property(nonatomic, assign) CLLocationCoordinate2D coordinate;

- (id)initWithCoordinate:(CLLocationCoordinate2D) c;
@end

自定义注释.m

#import "CustomAnnotation.h"

@implementation CustomAnnotation

@synthesize coordinate;

// ===========================================================================================================
- (id)initWithCoordinate:(CLLocationCoordinate2D) c
{
    self = [super init];
    if (!self) return nil;

    self.coordinate = c;

    return self;
}

// ===========================================================================================================
- (NSString*)subtitle 
{
    return @"";
}

// ===========================================================================================================
- (NSString*)title 
{
    return @"";
}

@end

我在每种方法中都尝试了断点，尝试使用环境变量启用 Zombies(但由于这需要在设备上运行，我不确定它们是否真的被激活)，没有任何解决方案的开始......我仍然不知道出了什么问题。

您知道如何解决 EXC_BAD_ACCESS 问题吗？
对于第二个问题的任何答案，如果不能解决崩溃，请使用评论而不是答案。据我所知，这个问题不是问题的核心。

提示:我在上面的代码中添加了 2 条注释，在那里我找到了一些解决方案。有 2 个地方似乎没有连接，可以从代码中取出一个或另一个来解决问题。让我抓狂的是手术室。

在 iPhone 4 ios 4.2.1 上运行

Answer 1

[self.myMapView removeAnnotation:self.myMapView.userLocation];

这条线导致堆栈跟踪崩溃，这是我所看到的。

当我看到 exc_bad_access 时，我在 gdb 中做了一个 bt。我添加了 Guard Malloc 断点。查看它所说的关于删除注释的堆栈。