Question

编辑：我在项目中使用ARC

我从plist加载注释：

[NSThread detachNewThreadSelector:@selector(loadPList) toTarget:self withObject:nil];

...

- (void) loadPList
{

    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *path = [[documentPaths lastObject] stringByAppendingPathComponent:@"test.plist"];

    NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path]; // memory leak here

    NSMutableArray *annotations = [[NSMutableArray alloc]init];


    dispatch_async(dispatch_get_main_queue(), ^{


        NSMutableArray * annotationsToRemove = [ mapView.annotations mutableCopy ] ;
        [ annotationsToRemove removeObject:mapView.userLocation ] ;
        [ mapView removeAnnotations:annotationsToRemove ] ;



        if ([[NSUserDefaults standardUserDefaults] boolForKey:@"blackKey"])
        {

            NSArray *ann = [dict objectForKey:@"Black"];

            for(int i = 0; i < [ann count]; i++) {

                NSString *coordinates = [[ann objectAtIndex:i] objectForKey:@"Coordinates"];

                double realLatitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:1] doubleValue];
                double realLongitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:0] doubleValue];

                MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];
                CLLocationCoordinate2D theCoordinate;
                theCoordinate.latitude = realLatitude;
                theCoordinate.longitude = realLongitude;

                myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);        
                myAnnotation.title = [[ann objectAtIndex:i] objectForKey:@"Name"];
                myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:@"Address"];
                myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:@"Icon"];

                [mapView addAnnotation:myAnnotation];
                [annotations addObject:myAnnotation];

            }

        }   


    });


}

所有载荷都很好，但内存泄漏工具向我显示泄漏。

leak screenshot

Answer 1

您需要将@autoreleasepool放在方法的开头 - 在其外部进行dictionaryWithContentsOfFile:调用，您将创建一个没有池的自动释放对象，因此它会泄漏。 Per the threading programming guide：

如果您的应用程序使用托管内存模型，请创建一个自动释放池应该是你在线程入口中做的第一件事常规。同样，破坏这个自动释放池应该是你在线程中做的最后一件事。

另外，我可以问你为什么要使用NSThread加载plist而不是dispatch_async()使用全局队列？我经常看不到dispatch_async()嵌套在一个线程分离中，所以只是好奇。

修改

要修复内存泄漏，不要打扰线程/ GCD混合，请按以下方式调用您的方法：

[NSThread detachNewThreadSelector:@selector(loadPList) toTarget:self withObject:nil];

并按照以下方式实施：

- (void) loadPList { @autoreleasepool { NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES); NSString *path = [[documentPaths lastObject] stringByAppendingPathComponent:@"test.plist"]; NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path]; // memory leak here NSMutableArray *annotations = [[NSMutableArray alloc]init]; dispatch_async(dispatch_get_main_queue(), ^{ NSMutableArray * annotationsToRemove = [ mapView.annotations mutableCopy ] ; [ annotationsToRemove removeObject:mapView.userLocation ] ; [ mapView removeAnnotations:annotationsToRemove ] ; if ([[NSUserDefaults standardUserDefaults] boolForKey:@"blackKey"]) { NSArray *ann = [dict objectForKey:@"Black"]; for(int i = 0; i < [ann count]; i++) { NSString *coordinates = [[ann objectAtIndex:i] objectForKey:@"Coordinates"]; double realLatitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:1] doubleValue]; double realLongitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:0] doubleValue]; MyAnnotation *myAnnotation = [[MyAnnotation alloc] init]; CLLocationCoordinate2D theCoordinate; theCoordinate.latitude = realLatitude; theCoordinate.longitude = realLongitude; myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude); myAnnotation.title = [[ann objectAtIndex:i] objectForKey:@"Name"]; myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:@"Address"]; myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:@"Icon"]; [mapView addAnnotation:myAnnotation]; [annotations addObject:myAnnotation]; } } } ); } }

Answer 2

如果没有别的，你需要一个自动释放池。要引用detachNewThreadSelector的文档，“方法aSelector负责为新分离的线程设置自动释放池，并在该池退出之前释放该池。”

就个人而言，我可能只是通过GCD而不是loadPlist调用detachNewThreadSelector，然后您不必担心自动释放池：

dispatch_async(get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    [self loadPlist];
});

Answer 3

NSMutableArray *annotations = [[NSMutableArray alloc]init]; // Never released
NSMutableArray * annotationsToRemove = [ mapView.annotations mutableCopy ] ; // Never released
MyAnnotation *myAnnotation = [[MyAnnotation alloc] init]; // Never released

您的方法应如下所示：

- (void) loadPList {
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *path = [[documentPaths lastObject] stringByAppendingPathComponent:@"test.plist"];
    NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path]; // memory leak here
    NSMutableArray *annotations = [[[NSMutableArray alloc] init] autorelease];
    dispatch_async(dispatch_get_main_queue(), ^{
        NSMutableArray * annotationsToRemove = [[mapView.annotations mutableCopy] autorelease];
        [annotationsToRemove removeObject:mapView.userLocation] ;
        [mapView removeAnnotations:annotationsToRemove] ;
        if ([[NSUserDefaults standardUserDefaults] boolForKey:@"blackKey"])
        {

            NSArray *ann = [dict objectForKey:@"Black"];

            for(int i = 0; i < [ann count]; i++) {

                NSString *coordinates = [[ann objectAtIndex:i] objectForKey:@"Coordinates"];

                double realLatitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:1] doubleValue];
                double realLongitude = [[[coordinates componentsSeparatedByString:@","] objectAtIndex:0] doubleValue];

                MyAnnotation *myAnnotation = [[[MyAnnotation alloc] init] autorelease];
                CLLocationCoordinate2D theCoordinate;
                theCoordinate.latitude = realLatitude;
                theCoordinate.longitude = realLongitude;

                myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);
                myAnnotation.title = [[ann objectAtIndex:i] objectForKey:@"Name"];
                myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:@"Address"];
                myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:@"Icon"];

                [mapView addAnnotation:myAnnotation];
                [annotations addObject:myAnnotation];

            }
        }   
    });
}

有人可以帮我解决内存泄漏吗？

3 个答案: