NSMutableArray线程安全(NSMutableArray thread safety)

 在我的应用程序中，我正在从多个线程访问和更改可变数组。 在开始时，当我尝试访问objectAtIndex对象时发生崩溃，因为索引超出了范围（该索引处的对象已经从另一个线程中的数组中移除）。 我在互联网上搜索如何解决这个问题，我决定尝试这个解决方案 。我做了一个NSMutableArray属性的类，请参阅以下代码： 
 
@interface SynchronizedArray()
@property (retain, atomic) NSMutableArray *array;
@end

@implementation SynchronizedArray

- (id)init
{
    self = [super init];
    if (self)
    {
        _array = [[NSMutableArray alloc] init];
    }
    return self;
}

-(id)objectAtIndex:(NSUInteger)index
{
    @synchronized(_array)
    {
        return [_array objectAtIndex:index];
    }
}

-(void)removeObject:(id)object
{
    @synchronized(_array)
    {
        [_array removeObject:object];
    }
}

-(void)removeObjectAtIndex:(NSUInteger)index
{
    @synchronized(_array)
    {
        [_array removeObjectAtIndex:index];
    }
}

-(void)addObject:(id)object
{
    @synchronized(_array)
    {
        [_array addObject:object];
    }
}

- (NSUInteger)count
{
    @synchronized(_array)
    {
        return [_array count];
    }
}

-(void)removeAllObjects
{
    @synchronized(_array)
    {
        [_array removeAllObjects];
    }
}

-(id)copy
{
    @synchronized(_array)
    {
        return [_array copy];
    }
}
 
 我使用这个类而不是旧的可变数组，但该应用程序仍在这条线上崩溃： return [_array objectAtIndex:index]; 我也试过这种方法与NSLock ，但没有运气。 我做错了什么以及如何解决这个问题？ 

In my app I'm accessing and changing a mutable array from multiple threads. At the beginning it was crashing when I was trying to access an object with objectAtIndex, because index was out of bounds (object at that index has already been removed from array in another thread). I searched on the internet how to solve this problem, and I decided to try this solution .I made a class with NSMutableArray property, see the following code:
 
@interface SynchronizedArray()
@property (retain, atomic) NSMutableArray *array;
@end

@implementation SynchronizedArray

- (id)init
{
    self = [super init];
    if (self)
    {
        _array = [[NSMutableArray alloc] init];
    }
    return self;
}

-(id)objectAtIndex:(NSUInteger)index
{
    @synchronized(_array)
    {
        return [_array objectAtIndex:index];
    }
}

-(void)removeObject:(id)object
{
    @synchronized(_array)
    {
        [_array removeObject:object];
    }
}

-(void)removeObjectAtIndex:(NSUInteger)index
{
    @synchronized(_array)
    {
        [_array removeObjectAtIndex:index];
    }
}

-(void)addObject:(id)object
{
    @synchronized(_array)
    {
        [_array addObject:object];
    }
}

- (NSUInteger)count
{
    @synchronized(_array)
    {
        return [_array count];
    }
}

-(void)removeAllObjects
{
    @synchronized(_array)
    {
        [_array removeAllObjects];
    }
}

-(id)copy
{
    @synchronized(_array)
    {
        return [_array copy];
    }
}
 
and I use this class instead of old mutable array, but the app is still crashing at this line: return [_array objectAtIndex:index]; I tried also this approach with NSLock, but without a luck. What I'm doing wrong and how to fix this?

原文：https://stackoverflow.com/questions/21139581