复制自定义对象

Question

我有一个名为Layer的对象,它有一些属性和一些方法.

我需要将Layer传递给第二个视图控制器:

SecondVC *view = [self.storyboard instantiateViewControllerWithIdentifier:@"2VC"];
view.Layer = [[Layer alloc] initWithMapLayer:self.Layer];
view.delegate = self;

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:view];
navController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

[self presentModalViewController:navController animated:YES];

在SecondVC中,我可能会更改属性.然后我通过委托返回Layer对象;

-(void)done
{
    [self.delegate returnLayer:self.layer];

    [self dismissModalViewControllerAnimated:YES];
}

现在我的问题是我将指针传递给我的第一个视图控制器的Layer对象,当我更新第二个视图控制器中的Layer时,我的第一个视图控制器的Layer对象也正在更新.

因为这个,我无法判断它是否已被更改(如果有,我需要运行一些代码).

我如何创建我的Layer对象的副本并将其传递给我的第一个视图控制器的Layer对象而不是指针？

编辑:

我尝试使用第二个init方法:

-(id)initWithLayer:(Layer *)Layer
{
    if (self = [super init])
    {
        self.call = [[FunctionCall alloc] init];        
        self.HUD = [[MBProgressHUD alloc] init];

        self.Layers = [[NSMutableDictionary dictionaryWithDictionary:Layer.Layers] copy];
        self.nameList = [[NSArray arrayWithArray:Layer.nameList] copy];
    }
    return self;
}

没有成功.

EDIT2:

试着

Layer *copyLayer = [self.myLayer copy];

layerView.myLayer = copyLayer;

并得到错误

-[layer copyWithZone:]: unrecognized selector sent to instance 0xfc72c40
2012-06-12 11:15:28.584 Landscout[8866:1fb07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Layer copyWithZone:]: unrecognized selector sent to instance 0xfc72c40'

解决了:

我在initWithLayer方法中添加了一个深层副本:

for (id key in layer.layers)
{
    [newLayers setValue:[[layer.layers objectForKey:key] mutableCopy] forKey:[key mutableCopy]];
}

for (id name in layer.nameList)
{
    [newList addObject:[name mutableCopy]];
}

这给了我一个Layer对象的副本

Answer 1

您需要为copy对象实现函数

在你的Layer.m中

- (id)copy
{
    Layer *layerCopy = [[Layer alloc] init];

    //YOu may need to copy these values too, this is a shallow copy
    //If YourValues and someOtherValue are only primitives then this would be ok
    //If they are objects you will need to implement copy to these objects too
    layerCopy.YourValues = self.YourValues;
    layerCopy.someOtherValue = self.someOtherValue;

    return layerCopy;
}

现在在你的通话功能

//instead of passing self.Layer pass [self.Layer copy]
view.Layer = [[Layer alloc] initWithMapLayer:[self.Layer copy]];