我有点疯狂地试图归档和取消归档一个 UIImageView,它有许多子视图,这些子视图是从 UIImageView 派生的自定义视图。这是我所做的:
为项目添加一个类别以允许 UIImage 不符合 NSCoding 的事实:
#import "UIImage-NSCoding.h"
#define kEncodingKey @"UIImage"
@implementation UIImage(NSCoding)
- (id)initWithCoder:(NSCoder *)decoder
{
if ((self = [super init]))
{
NSData *data = [decoder decodeObjectForKey:kEncodingKey];
self = [self initWithData:data];
}
return self;
}
- (void)encodeWithCoder:(NSCoder *)encoder
{
NSData *data = UIImagePNGRepresentation(self);
[encoder encodeObject:data forKey:kEncodingKey];
}
@end
我正在归档的 UIImageView 是我的主视图控制器的一个属性,称为“背景”。我这样保存:
NSData *dataToSave = [NSKeyedArchiver archivedDataWithRootObject:self.background];
[dataToSave dataWithContentsOfFile:imagePath options:NSDataWritingAtomic error:nil];
然后我像这样解压它:
NSData *savedData = [NSData dataWithContentsOfFile:imagePath];
UIImageView *restoredImageView = [NSKeyedUnarchiver unarchiveObjectWithData:savedData];
self.background.image = restoredImageView.image; // this works - archived image is displayed
现在我想让我的子视图(或至少其中一个!)与未归档的根对象一起显示:
NSLog(@"Subviews: %d", [restoredImageView.subviews count]); // this tells me my subviews have been archived along with the root object
NSLog(@"Subview 0: %@", [restoredImageView.subviews objectAtIndex:0]); // and they exist as expected
NSLog(@"Subviews: %d", [self.background.subviews count]); // at this point no subviews are present
[self.background addSubview:[restoredImageView.subviews objectAtIndex:0]]; // subview is not visible on screen
NSLog(@"Subviews: %d", [self.background.subviews count]); // count is one, but where is it?
ORUImageView *oru = [[ORUImageView alloc] init]; // I try creating the subview myself
oru = [self.background.subviews objectAtIndex:0];
[self.background addSubview:oru]; // it still doesn't show on screen
[self.background bringSubviewToFront:oru]; // makes no difference
NSLog(@"String: %@", oru.testString); // this correctly logs the test string I added to my custom class
这是我添加到我的 ORUImageView 子类的内容:
- (void)encodeWithCoder:(NSCoder *)aCoder
{
[super encodeWithCoder:aCoder];
[aCoder encodeObject:self.testString forKey:@"theString"];
[aCoder encodeObject:self.image forKey:@"theImage"]; // not sure if this is needed
}
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
[self setTestString:[aDecoder decodeObjectForKey:@"theString"]];
[self setImage:[aDecoder decodeObjectForKey:@"theImage"]]; // not sure if this is needed
return self;
}
我已经尝试过使用和不使用 image 属性的编码。
我怀疑问题与此属性有关,因为我显然将子视图添加到未归档视图中 - 它只是不可见!我觉得图像属性没有设置,但我找不到自己设置的方法,也找不到任何告诉我正确方法的东西。