iPhone 和模拟器上的 EXC_BAD_ACCESS 问题

Question

我在自己的代码之外得到了 EXC_BAD_ACCESS 。目前我的代码通过 shareURLCache 对象获取 URL，然后启动 url 连接。一旦我离开启动 url 连接的方法，我就会遇到 EXC_BAD_ACCESS。我尝试使用仪器来查找任何僵尸，并且分析了内存泄漏，但也没有出现。此时我完全陷入困境。

下面是加载 url 并

- (void)locationManager:(CLLocationManager *)manager 
didUpdateToLocation:(CLLocation *)newLocation 
       fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"At new location: %@",newLocation);

    MKCoordinateRegion region = 
            MKCoordinateRegionMakeWithDistance([newLocation coordinate], 750, 750);

    [mapView setRegion:region animated:YES];
    [location stopUpdatingLocation];

    CLLocationCoordinate2D coord = [newLocation coordinate];
    NSURL *url = [urlCache getReccomendationForUID:@"12345" atLat:coord.latitude 
                                         atLon:coord.longitude forCategories:nil];


    // Create the request.
    NSURLRequest *request = [NSURLRequest requestWithURL:url
                                         cachePolicy:NSURLRequestUseProtocolCachePolicy
                                     timeoutInterval:60.0];


// create the connection with the request
// and start loading the data
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
    if (connection) {
        // Create the NSMutableData to hold the received data.
        // xmlData is an instance variable declared elsewhere.
        xmlData = [[NSMutableData alloc]init];
    } else {
        NSLog(@"Could not create connection");
    }
}

从返回 url 的共享 URLCache 中启动 url 连接方法的代码

-(NSURL *)getReccomendationForUID:(NSString *)u atLat:(double)lat atLon:(double)lon forCategories:(NSArray *)cat
{
    if(remote) {
        NSMutableString *categories = [[NSMutableString alloc]init];
        for(NSString *s in cat) {
            [categories appendString:@"&cat="];
            [categories appendString:s];
        }
        NSString *s = [NSString stringWithFormat:@"%@/recommendation?uid=%@&psw=null&lat=%f&lon=%f?%@",
                   apiRoot,u,lat,lon,categories];
        [categories release];
        return [NSURL URLWithString:s];
    } else {
        return [[NSBundle mainBundle] URLForResource:@"XMLTest" withExtension:@"xml"];;
    }
}

Answer 1

只需首先注释掉代码并运行，看看是否可以让内存错误消失，然后再次开始添加代码，直到它出现，然后您就可以更好地了解问题出在哪里。它可能位于代码中的任何位置，因为其中似乎有许多对象未传入“位置”等。

[location stopUpdatingLocation];

Answer 2

我有同样的内存问题，

[mapView setRegion:region animated:YES];

这种方法不喜欢快速更新......