我有一个贴纸类，我正在将贴纸对象保存到NSMutableDictionary中。贴纸类别如下：
#import "Sticker.h"
@implementation Sticker
-(instancetype)initWithTitle:(NSString *)title stickerNO:(int)stickerNO image:(UIImage *)image {
self=[super init];
if(self){
self.title=title;
self.stickerNO=[NSNumber numberWithInt:stickerNO];;
self.image=image;
}
return self;
}
//CODING METHODS//////////////
-(void)encodeWithCoder:(NSCoder *)aCoder{
//choose what we save, these are objects
[aCoder encodeObject:self.title forKey:@"title"];
[aCoder encodeObject:self.stickerNO forKey:@"stickerNO"];
[aCoder encodeObject:self.image forKey:@"image"];
}
-(instancetype)initWithCoder:(NSCoder *)aDecoder
{
self=[super init];
if(self){
self.title=[aDecoder decodeObjectForKey:@"title"];
self.stickerNO=[aDecoder decodeObjectForKey:@"stickerNO"];
self.image=[aDecoder decodeObjectForKey:@"image"];
}
return self;
}
@end
字典由StickerManager:类管理
@implementation StickerManager
-(instancetype)init {
self = [super init];
//load the dictionary
NSString *path = [self itemArchivePath];
self.stickerDictionary=[NSKeyedUnarchiver unarchiveObjectWithFile:path];
//if there is no dictionary create it and add the default
if(!self.stickerDictionary) {
NSLog(@"Creating dictionary and adding default");
self.stickerDictionary=[[NSMutableDictionary alloc] init];
[self addDefaultStickers];
[self saveStickerDictionary];
}
//if empty fill it
else if ([self.stickerDictionary count]==0){
NSLog(@"Dictionary exists but it empty");
[self addDefaultStickers];
[self saveStickerDictionary];
}
return self;
}
//add the stickers included in the app bundle
-(void)addDefaultStickers {
Sticker *sticker = [[Sticker alloc] initWithTitle:@“Batman” stickerNO:1 image:[UIImage imageNamed:@“batman.png"]];
[self.stickerDictionary setObject:sticker forKey:sticker.title];
}
-(BOOL)saveStickerDictionary{
NSLog(@"Saving stickers");
//get the path from above
NSString *path = [self itemArchivePath];
return [NSKeyedArchiver archiveRootObject:self.stickerDictionary toFile:path];
}
-(NSString *)itemArchivePath
{
//get the directory
NSArray *documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//set it to a string
NSString *documentDirectory = [documentDirectories firstObject];
//here we call the file items.archive
return [documentDirectory stringByAppendingPathComponent:@"stickers.archive"];
}
@end
如果StickerManager是init，如果它是空的或不存在，它将通过调用addDefaultStickers创建并用默认的贴纸填充字典。这适用于我在代码中的一个贴纸。我可以加载和恢复字典，并使用NSLog检查内容。贴纸在那里，但由于某种原因，UIImage为空，我无法显示它。我真的不确定为什么，我已经为它使用了encodeWithCoder，所以它不应该工作吗？奇怪的是，如果我从Parse.com下载一个贴纸（我在上面有一个相同的类），然后将该图像从NSData转换为png并保存它就可以了。有人能告诉我这里可能出了什么问题吗？感谢
编辑这是我从Parse.com下载的代码：
- (void)getNewStickersWithCompletionHandler:(stickerCompletionHandler)handler
{
__weak StickerManager *weakSelf = self;
PFQuery *stickersQuery = [PFQuery queryWithClassName:@"sticker"];
[stickersQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if(!error) {
for( PFObject *object in objects) {
NSString *title = object[@"title"];
int stickerNO = [[object objectForKey:@"stickerNO"] intValue];
//DOWNLOAD IMAGE CODE
PFFile *image = object[@"image"];
[image getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if(!error){
UIImage *image = [UIImage imageWithData:data];
Sticker *sticker = [[Sticker alloc] initWithTitle:title stickerNO:stickerNO image:image];
[weakSelf.stickerDictionary setObject:sticker forKey:sticker.title];
[self saveStickerDictionary];
handler(YES,nil);
}
}];//end get image block
}//end for
}
}];//end download stickers block
}
如果我以这种方式将贴纸保存到字典中，就没有问题，并且我可以显示图像。这几乎与addDefaultStickers相同，我正在保存UIImage，而不是保存NSData。不知道上面是什么。。
仅供他人参考，问题在于没有首先将UIImage转换为NSData。我将aCoder方法中的UIImage行更改为以下行：
[aCoder encodeObject:UIImagePNGRepresentation(self.image) forKey:@"image"];
在aDecoder:self.image = [UIImage imageWithData:[aDecoder decodeObjectForKey:@"image"]]; 中
我不完全理解为什么它适用于之前被转换为解析下载的UIImage的NSData，但现在一切都正常了。