Core Data相关之配置数据存储
本代码是在应用沙盒目录下创建一个Stores文件夹，然后在文件夹中创建Grocery-Dude.sqlite文件。
1.获取应用程序文档路径（两种方法，注意两种方法返回路径不同）
//这是应用程序文档目录的路径
/Users/apple/Library/Application Support/iPhone Simulator/4.3/Applications/550AF123-1711-3124-881B-54329FAA32B7/Documents
- (NSString *)applicationDocumentsDirectory {
return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES) lastObject];
}
//这是应用程序目录的路径
/Users/apple/Library/Application Support/iPhone Simulator/4.3/Applications/550AF26D-174B-42E6-881B-B7499FAA32B7/
- (NSString *)applicationDirectory{
return NSHomeDirectory();
}
2.在程序文档目录中添加名为Stores的子目录，并将其路径放在URL中返回，若Stores目录尚未建立，则建立。
api详解：
//判断路径是否有效
- (BOOL)fileExistsAtPath:(NSString *)path;
//根据url创建目录
//createIntermediates为YES可以创建多级目录,NO创建一级目录
//attributes字典类型，配置这个文件信息如创建时间，读写等
//error如果创建失败，可以通过error打印失败原因
- (BOOL)createDirectoryAtURL:(NSURL *)url
withIntermediateDirectories:(BOOL)createIntermediates
attributes:(NSDictionary *)attributes
error:(NSError **)error
- (NSURL *)applicationStoresDirectory {
NSURL *storesDirectory =
[[NSURL fileURLWithPath:[self applicationDocumentsDirectory]]URLByAppendingPathComponent:@"Stores"];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath:[storesDirectory path]]) {
NSError *error = nil;
if ([fileManager createDirectoryAtURL:storesDirectory
withIntermediateDirectories:YES
attributes:nil
error:&error]) {
if (debug==1) {
NSLog(@"Successfully created Stores directory");}
}
else {NSLog(@"FAILED to create Stores directory: %@", error);}
}
return storesDirectory;
}
3.将Grocery-Dude.sqlite添加到URL路径中并返回
- (NSURL *)storeURL {
return [[self applicationStoresDirectory]URLByAppendingPathComponent:storeFilename];
//返回的是一个具体到Grocery-Dude.sqlite的URL
}
4.配置数据存储
//storeTypeg共四种类型SQLite，XML，Binary，InMemory
//storeURL及数据存储在文档中的URL地址
//- (NSPersistentStore *)addPersistentStoreWithType:(NSString *)storeType
configuration:(NSString *)configuration
URL:(NSURL *)storeURL
options:(NSDictionary *)options
error:(NSError **)error;
数据存储的声明
@property (nonatomic, readonly) NSPersistentStore *store;
_store = [_coordinator addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil
URL:[self storeURL]
options:nil error:&error];
参考资料：
「Learning Core Data for iOS」示例代码