我正在为 iPhone 应用程序编写一些代码,但在正确加载默认数据时遇到问题。我的代码基于 Ray Wenderlich 的“Learning Cocos2d”一书中的一些示例。
似乎即使当我彻底删除应用程序并尝试从新数据开始时,应用程序也不一致地不尝试加载数据,或者错误地认为有数据并加载 null。
我正在使用 containsValueForKey 检查值是否存在,然后加载它或加载一些默认值,但即使在全新安装时, containsValueForKey 也会找到数据并且不加载默认值。在 xcode 的管理器中,我检查了我设备的文件结构和我指定保存的 Documents 文件夹,它看起来不包含任何文件,所以我不确定它在抓取什么。
我的猜测是问题与 initWithCoder 函数有关。它有时似乎神秘地通过了该功能,但并非一直如此。另一个奇怪的事情是,[[GameManager sharedGameManager] save]
当玩家获得高分时我会调用(此处未显示,但代码与此objectiveList 完全相同,只是一个int)并且它似乎正确保存了它。
现在代码:
GC数据库.h
#import <Foundation/Foundation.h>
id loadData(NSString * filename);
void saveData(id theData, NSString *filename);
GC数据库.m
#import "GCDatabase.h"
NSString * pathForFile(NSString *filename) {
// 1
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
// 2
NSString *documentsDirectory = [paths objectAtIndex:0];
// 3
return [documentsDirectory stringByAppendingPathComponent:filename];
}
id loadData(NSString * filename) {
NSString *filePath = pathForFile(filename);
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSData *data = [[[NSData alloc] initWithContentsOfFile:filePath] autorelease];
NSKeyedUnarchiver *unarchiver = [[[NSKeyedUnarchiver alloc] initForReadingWithData:data] autorelease];
id retval = [unarchiver decodeObjectForKey:@"Data"];
[unarchiver finishDecoding];
return retval;
}
return nil;
}
void saveData(id theData, NSString *filename) {
NSMutableData *data = [[[NSMutableData alloc] init] autorelease];
NSKeyedArchiver *archiver = [[[NSKeyedArchiver alloc] initForWritingWithMutableData:data] autorelease];
[archiver encodeObject:theData forKey:@"Data"];
[archiver finishEncoding];
[data writeToFile:pathForFile(filename) atomically:YES];
}
游戏管理器.h
@interface GameManager : NSObject <NSCoding>{
NSMutableArray *objectiveDescriptions;
}
@property (nonatomic, retain) NSMutableArray * objectiveDescriptions;
+(GameManager*)sharedGameManager;
-(void)save;
-(void)load;
-(void)encodeWithCoder:(NSCoder *)encoder;
-(id)initWithCoder:(NSCoder *)decoder;
@end
GameManager.m(我添加了加载功能,试图强制它加载,但它似乎不起作用)
+(GameManager*)sharedGameManager {
@synchronized([GameManager class])
{
if(!sharedGameManager) {
sharedGameManager = [loadData(@"GameManager") retain];
if (!sharedGameManager) {
[[self alloc] init];
}
}
return sharedGameManager;
}
return nil;
}
+(id)alloc {
@synchronized([GameManager class]){
NSAssert(sharedGameManager == nil, @"Attempted to allocate a second instance of the Game Manager singleton");
sharedGameManager = [super alloc];
return sharedGameManager;
}
return nil;
}
- (void)dealloc {
[objectiveList release];
[super dealloc];
}
- (void)save {
saveData(self, @"GameManager");
}
-(void)load {
loadData(@"GameManager");
}
- (void)encodeWithCoder:(NSCoder *)encoder {
[encoder encodeObject:objectiveList forKey:@"objectiveList"];
}
- (id)initWithCoder:(NSCoder *)decoder {
self = [super init];
if (self != nil) {
if ([decoder containsValueForKey:@"objectiveList"]) {
objectiveList = [decoder decodeObjectForKey:@"objectiveList"];
} else {
[objectiveList addObjectsFromArray:[NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5", nil]];
}
}
return self;
}
@end