我正在使用UIManagedDocument
来阅读和写入CoreData
。我有Document
课。这是一些教程中的文档:
·H
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
typedef void (^OnDocumentReady) (UIManagedDocument *document);
@interface Document : NSObject
@property (strong, nonatomic) UIManagedDocument *document;
+ (Document *)sharedDocument;
- (void)performWithDocument:(OnDocumentReady)onDocumentReady;
@end
的.m
@interface Document ()
- (void)objectsDidChange:(NSNotification *)notification;
- (void)contextDidSave:(NSNotification *)notification;
@end;
@implementation Document
@synthesize document = _document;
static Document*_sharedInstance;
+ (Document *)sharedDocument
{
static dispatch_once_t once;
dispatch_once(&once, ^{
_sharedInstance = [[self alloc] init];
});
return _sharedInstance;
}
- (id)init {
self = [super init];
if (self) {
NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
url = [url URLByAppendingPathComponent:@"Document"];
self.document = [[UIManagedDocument alloc] initWithFileURL:url];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
self.document.persistentStoreOptions = options;
// Register for notifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(objectsDidChange:)
name:NSManagedObjectContextObjectsDidChangeNotification
object:self.document.managedObjectContext];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(contextDidSave:)
name:NSManagedObjectContextDidSaveNotification
object:self.document.managedObjectContext];
}
return self;
}
- (void)performWithDocument:(OnDocumentReady)onDocumentReady
{
void (^OnDocumentDidLoad)(BOOL) = ^(BOOL success) {
onDocumentReady(self.document);
};
if (![[NSFileManager defaultManager] fileExistsAtPath:[self.document.fileURL path]]) {
[self.document saveToURL:self.document.fileURL
forSaveOperation:UIDocumentSaveForCreating
completionHandler:OnDocumentDidLoad];
} else if (self.document.documentState == UIDocumentStateClosed) {
[self.document openWithCompletionHandler:OnDocumentDidLoad];
} else if (self.document.documentState == UIDocumentStateNormal) {
OnDocumentDidLoad(YES);
}
}
- (void)objectsDidChange:(NSNotification *)notification
{
#ifdef DEBUG
NSLog(@"NSManagedObjects did change.");
#endif
}
- (void)contextDidSave:(NSNotification *)notification
{
#ifdef DEBUG
NSLog(@"NSManagedContext did save.");
#endif
}
@end
然后在ViewController
我有NSURLConnection
:
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
DataParser *parser = [[DataParser alloc] init];
[parser startParsingData:self.myMutableData withContext:self.moc];
}
我在这里打开文件:
-(void)initDocument {
if (!self.moc) {
[[Document sharedDocument] performWithDocument:^(UIManagedDocument *document) {
self.moc = document.managedObjectContext;
[[NSNotificationCenter defaultCenter] postNotificationName:UIDocumentStateChangedNotification object:self];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:@"someURL"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60];
[NSURLConnection connectionWithRequest:request delegate:self];
}];
}
}
然后我尝试解析数据:
-(void)startParsingData:(NSData*)data withContext:(NSManagedObjectContext*)context {
self.moc = context;
self.startDate = [NSDate date];
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
parser.delegate = self;
[parser parse];
}
在XML
解析后尝试将其加载到核心数据中:
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
if([elementName isEqualToString:@"Item"]) {
[self.moc performBlockAndWait:^{
TestEntity *te = [NSEntityDescription insertNewObjectForEntityForName:@"TestEntity" inManagedObjectContext:self.moc];
te.surname = @"5433fds";
te.name = @"5342fdsfsd";
}];
}
}
我看到了日志:
2014-01-24 16:21:21.692 Ce[85149:70b] NSManagedObjects did change.
2014-01-24 16:21:36.696 Ce[85149:70b] NSManagedContext did save.
所以我假设这应该在sqlite文件中,但是当我尝试读取它时它是完全空的。 awl
文件有一些更大的大小,但persistentStore有0行。为什么?
答案 0 :(得分:3)
第二次启动应用时会发生什么,您能否在应用中看到数据?
在iOS 7中,SQLite现在启用了日记功能。我想知道日志是否会引起混淆(数据存在,但在sqlite文件中却没有)。
我还会质疑你使用UIManagedDocument
的原因。看来你正在以单例模式使用核心数据(这很糟糕),然后在该单例模式中使用UIManagedDocument
(更糟糕)。
UIManagedDocument
适用于基于文档的应用。如果您构建了标准的Core Data堆栈,那么您可能会对该类中的某些“自动”功能进行犯规,这些功能很容易被清除。
您可以考虑关闭日记功能,为NSPersistentStoreCoordinator
添加真空选项或切换到标准核心数据堆栈。
答案 1 :(得分:0)
这可能是因为iOS 7中使用了新的SQLite日记帐模式。如果您将其设置为旧模式,如以下SO问题的答案所示,您应该再次看到您的数据。