摘要:
1、UIManagedDocument-(void)saveToURL:(NSURL *)url forSaveOperation:(UIDocumentSaveOperation)saveOperation completionHandler:(void (^)(BOOL success))completionHandler-(void)openWithCompletionHandler:(void (^)(BOOL success))completionHandleropen和save方法都是异步的asynchronous,所以其需要一个completionBlock来执行open或sav 阅读全文