存档和取消存档会导致访问权限错误 [英] Archiving and Unarchiving results in Bad Access

问题描述

我在设置模型对象时遇到问题，无法在iPhone的简单图形应用程序中保存用户生成的CALayers的可视状态。

I'm having trouble setting up a model object to save the visual state of user generated CALayers in a simple graphics application for the iphone.

通过将这些属性传递到实现NSCoding协议的模型对象，然后到应用程序代理拥有的NSMutableArray，保存屏幕上所有当前图层的背景颜色和框架。然后我使用NSKeyedArchiver归档数组，并将其存储在NSUserDefaults中。

I'm attempting to save the background color and frame of all the current layers on screen by passing those properties to model objects which implement the NSCoding protocol and then into an NSMutableArray which the app delegate owns. Then I archive the array with NSKeyedArchiver and store it in the NSUserDefaults.

每个CALayer的backgroundColor属性都被转换为UIColor，我认为我unarchiving阵列不正确或没有正确地从未归档的数组恢复状态。当我试图访问存储在模型对象中的UIColor对象时，我得到一个EXC_BAD_ACCESS。

Each CALayer's backgroundColor property is converted to a UIColor to be encoded by the model object for storage. I think that I'm unarchiving the array incorrectly or not restoring state from the unarchived array correctly. When I attempt to access the UIColor object that was store in the model object, I get an EXC_BAD_ACCESS.

我认为这可能是编码UIColor对象的错误，所以试图通过CGColorGetComponents函数从CGColorRef中提取值，并将它们存储在数组中进行编码和存档，

I thought it was possibly a bug with encoding UIColor objects so tried pulling the values out of the CGColorRef with the CGColorGetComponents function and storing them in an array to encode and archive, but I had the same result of bad access after unarchiving, so I think I'm just doing it wrong.

这是我的模型对象：

@interface AILayerData : NSObject <NSCoding> {

    UIColor*    color;
    CGRect      frame;
}

@property (retain) UIColor* color;
@property (assign) CGRect   frame;

@end


@implementation AILayerData

@synthesize color;
@synthesize frame;

- (void)encodeWithCoder:(NSCoder *)coder; 
{
    [coder encodeObject:color forKey:@"color"];
    [coder encodeCGRect:frame forKey:@"frame"];
}


- (id)initWithCoder:(NSCoder *)coder;
{
    self = [[AILayerData alloc] init];
    if (self != nil)
    {
        color = [coder decodeObjectForKey:@"color"];
        frame = [coder decodeCGRectForKey:@"frame"];
    }
    return self;
}

@end

这是我的归档实现：

@implementation AppDelegate

- (void)applicationWillTerminate:(UIApplication *)application {

    NSArray *layersArray = viewController.view.layer.sublayers;

    dataArray = [NSMutableArray array]; 

    for(AILayer *layer in layersArray)
    {
        AILayerData *layerData = [[AILayerData alloc] init];

        layerData.frame = layer.frame;

        UIColor *layerColor = [UIColor colorWithCGColor:layer.backgroundColor];

        layerData.color = layerColor;               

        [dataArray addObject:layerData];

        [layerData release];

    }

    [[NSUserDefaults standardUserDefaults] setObject:[NSKeyedArchiver archivedDataWithRootObject:layerDataArray] forKey:@"savedArray"];
}

@end

状态：

@implementation ViewController

- (void)viewDidLoad 
{    
    [super viewDidLoad];

    spaceView = [[AISpaceView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    self.view = spaceView;

    [spaceView release];

    spaceView.delegate = self;

    NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];

    NSData *dataRepresentingSavedArray = [currentDefaults objectForKey:@"savedArray"];

    if (dataRepresentingSavedArray != nil) {

        [self restoreStateWithData:dataRepresentingSavedArray];

    }
}

- (void)restoreStateWithData:(NSData *)data 
{   
    NSArray *savedLayers = [NSKeyedUnarchiver unarchiveObjectWithData:data];

    if (savedLayers != nil) {

        NSArray *restoredLayers = [[NSArray alloc] initWithArray:savedLayers];

        for(AILayerData *layerDataObject in restoredLayers) {                       

            UIColor *layerColor = layerDataObject.color;

            AILayer *newLayer = [[AILayer alloc] init];         

            newLayer.backgroundColor = layerColor.CGColor;

            newLayer.frame = layerDataObject.frame;         

            newLayer.isSelected = NO;

            [self.view.layer addSublayer:newLayer];

            [newLayer release];                                 
        }

        [restoredLayers release];

        [spaceView.layer layoutSublayers];      
    }
}

@end

帮助这是非常感谢。我几乎是一个noob。我正在编码，归档和解除NSNumbers的NSArray从颜色的浮动以非常相同的方式转换，并获得访问不良。

Any help with this is greatly appreciated. I'm pretty much a noob. I was encoding, archiving and unarching an NSArray of NSNumbers converted from the color's floats in pretty much the same way and getting bad access.

推荐答案

p>你肯定希望保留initWithCoder中的颜色：

You certainly want to retain the color in initWithCoder:

color = [[coder decodeObjectForKey:@"color"] retain];

或将点语法作为颜色声明为 retain 属性：

or, with the dot syntax as color was declared as a retain property:

self.color = [coder decodeObjectForKey:@"color"];

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