Could not create UIManagedDocument - ios

Question

I'm trying to make an iPhone app using Core Data. I have to use NSManagedObjectContext to access data and in order to do this i use UIManagedDocument. But if I try to create a document with UIManagedDocument, document's openWithCompletionHandler isn't success. This why my NSManagedObjectContext is always nil and Xcode says could not create document at etc. Here are the classes:
AddUserViewController.h
#import <UIKit/UIKit.h>
#interface AddUserViewController : UIViewController
#property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;
#property (nonatomic,strong) UIManagedDocument *document;
#end
AddUserViewController.m
#import "AddUserViewController.h"
#import "User.h"
#import "User+Create.h"
#interface AddUserViewController ()
#property (weak, nonatomic) IBOutlet UITextField *nameField;
#property (weak, nonatomic) IBOutlet UITextField *ageField;
#property (weak, nonatomic) IBOutlet UITextField *sexField;
#property (weak, nonatomic) IBOutlet UITextField *weightField;
#property (weak, nonatomic) IBOutlet UITextField *activityField;
#end
#implementation AddUserViewController
-(void)setManagedObjectContext:(NSManagedObjectContext *)managedObjectContext{
_managedObjectContext = managedObjectContext;
}
-(void)createOrWriteDocument{
NSURL *url = [[[NSFileManager defaultManager]URLsForDirectory:NSDocumentationDirectory inDomains:NSUserDomainMask]firstObject];
url = [url URLByAppendingPathComponent:#"Activities"]; // edited mistakenly deleted
self.document = [[UIManagedDocument alloc] initWithFileURL:url];
if ([[NSFileManager defaultManager] fileExistsAtPath:[url path]]) {
[self.document openWithCompletionHandler:^(BOOL success) {
if (success) [self documentIsReady];
if (!success){
NSLog(#"could not open document at %#",url);
}
}];
} else {
[self.document saveToURL:url
forSaveOperation:UIDocumentSaveForCreating
completionHandler:^(BOOL success) {
if (success) {
[self documentIsReady];
}
if (!success){
NSLog(#"could not create document at %#",url);
}
}];
}
}
- (void)documentIsReady
{
if (self.document.documentState == UIDocumentStateNormal) {
self.managedObjectContext = self.document.managedObjectContext;
} }
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
if (!self.managedObjectContext) {
[self createOrWriteDocument];
}
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(dismissKeyboard)];
[self.view addGestureRecognizer:tap];
}
-(void)dismissKeyboard{
[self.nameField resignFirstResponder];
[self.ageField resignFirstResponder];
[self.sexField resignFirstResponder];
[self.weightField resignFirstResponder];
[self.activityField resignFirstResponder];
}
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([segue.identifier isEqualToString:#"setUser:"]) {
//User *user = [[User alloc]init];
User *user = [User createUserWithname:self.nameField.text
withAge:[NSNumber numberWithDouble:[self.ageField.text doubleValue]]
withSex:self.sexField.text
withWeight:[NSNumber numberWithDouble:[self.weightField.text doubleValue]]
withActivity:self.activityField.text
inManagedObjectContext:self.managedObjectContext];
if ([segue.destinationViewController respondsToSelector:#selector(setUser:)]) {
[segue.destinationViewController performSelector:#selector(setUser:) withObject:user];
}
}
}
#end
EDIT
I solved the problem.Problem is at the NSURL *url = [[[NSFileManager defaultManager]URLsForDirectory:NSDocumentationDirectory inDomains:NSUserDomainMask]firstObject];
line. Instead of NSDocumentationDirectory, I used NSDocumentDirectory and it solved the problem.

Answer 1

You can try this code to create you managedobjectcontext.
- (NSManagedObjectContext *) managedObjectContext
{
if (_managedObjectContext != nil) {
return _managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
[_managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return _managedObjectContext;
}

Answer 2

Take a look at the example below. This works for me, sorry don't have time to take a closer look to see the differences, I am using iCloud options so remove them but try setting the other persistentStoreOptions. And also post details of the error are you getting?
// This gets called when the user has done one of the following:
// 1. Created a new file and entered a new file name. We have then created the fileURL
// using the /Documents directory, the filename and appending '_UUID_'+uuid to ensure that
// avoid duplicate file names in case the user used the same file name on another device.
// 2. Selected an existing file from the file browser
//
- (void)createNewFile:(NSURL*)fileURL {
//FLOG(#"createNewFile called with url %#", fileURL);
_creatingNewFile = YES; // Ignore any file metadata scan events coming in while we do this because some iCloud
// files get created by Core Data before the local files are created and our scanning
// picks up new iCloud files and attempts to create local copies and we don't want this
// if this devices is busy creating the new iCloud file
_document = [[OSManagedDocument alloc] initWithFileURL:fileURL];
// Set oberving on this file to monitor the state (we don't use it for anything other than debugging)
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self
selector:#selector(documentStateChanged:)
name:UIDocumentStateChangedNotification
object:_document];
_openedVersion = [NSFileVersion currentVersionOfItemAtURL:fileURL];
_openedVersionDate = _openedVersion.modificationDate;
_openedVersionDevice = _openedVersion.localizedNameOfSavingComputer;
//FLOG(#" file version date: %#", _openedVersionDate);
//FLOG(#" file version device: %#", _openedVersionDevice);
NSString *fileName = [[fileURL URLByDeletingPathExtension] lastPathComponent];
[_document setPersistentStoreOptions:#{NSPersistentStoreUbiquitousContentNameKey:fileName,
NSMigratePersistentStoresAutomaticallyOption:#YES,
NSInferMappingModelAutomaticallyOption:#YES,
NSSQLitePragmasOption:#{ #"journal_mode" : #"DELETE" }}];
_managedObjectContext = _document.managedObjectContext;
if ([[NSFileManager defaultManager] fileExistsAtPath:[fileURL path]]) {
//FLOG(#" file exists so open it: %#",fileURL);
[_document openWithCompletionHandler:^(BOOL success){
if (!success) {
// Handle the error.
LOG(#" error creating file");
} else {
//LOG(#" file opened");
[self fileOpened]; // Now initialise the UI and let the user continue...
}
}];
}
else {
// File does not exist so that means the user has created a new one and we need to
// load some initialisation data into the Core Data store (codes tables, etc.)
//
// At this stage we have a database in memory so we can just use the _document.managedObjectContext
// to add objects prior to attempting to write to disk.
//LOG(#" file DOES NOT exist so add initial data");
[self addInitialData];
// Just checking if anything has been written to disk, nothing should not exist on disk yet.
// Debugging use only
if ([[NSFileManager defaultManager] fileExistsAtPath:[fileURL path]])
LOG(#" file exists but keep going anyway :-(");
else
LOG(#" file still does not exist :-)");
// OK now save a copy to disk using UIManagedDocument
// NOTE: the iCloud files are written before the UIManagedDocument.fileURL, presumably because Core Data does this setup
// in response to the [moc save:]. Make sure we don't pick this up in our iCloud metaData scan and attempt to create
// it as if it were a new iCloud file created by some other device.
//
[_document saveToURL:_document.fileURL forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success){
if (!success) {
// Handle the error.
LOG(#" error saving file :-(");
}
// We close the file and wait for it to appear in the file browser and then
// let the user select it from the browser to open it and start using it.
// Skip this if you want to open it directly and [self fileopened] but
// bear in mind the fileListController will not be correctly set up when we return to it.
[_document closeWithCompletionHandler:^(BOOL success){
if (!success) {
// Handle the error.
LOG(#" error closing file after creation :-(");
FLOG(#" file URL is %#", [fileURL path]);
} else {
FLOG(#" file closed %#", fileName);
_creatingNewFile = NO; // OK we are done, so let metaData scanning go ahead as normal
// Tell our UITableView file list that we are done and trigger scanning of local and iCloud files
// The fileListController will the add the new file itself and the user will then pick the
// file from this list in order to open it.
// To open the file automatically use the callback in the fileListController
// to select and then open the file so it looks seamless to the user.
[self.fileListController fileHasBeenCreated:fileURL];
// Stop observing now
[center removeObserver:self
name:UIDocumentStateChangedNotification
object:_document];
}
}];
}];
}
}
Oh and also create a subclass of UIManagedDocument so you can get the errors, if you don't already have one. All you need is the following in the subclass.
#implementation OSManagedDocument
- (id)contentsForType:(NSString *)typeName error:(NSError *__autoreleasing *)outError
{
LOG(#"Auto-Saving Document");
return [super contentsForType:typeName error:outError];
}
- (void)handleError:(NSError *)error userInteractionPermitted:(BOOL)userInteractionPermitted
{
FLOG(#" error: %#", error.localizedDescription);
NSArray* errors = [[error userInfo] objectForKey:NSDetailedErrorsKey];
if(errors != nil && errors.count > 0) {
for (NSError *error in errors) {
FLOG(#" Error: %#", error.userInfo);
}
} else {
FLOG(#" error.userInfo = %#", error.userInfo);
}
}
#end
This is the method to get the /Documents directory on the device. The file name is appended to this path.
- (NSURL*)documentsDirectoryURL
{
_dataDirectoryURL = [NSURL fileURLWithPath:NSHomeDirectory() isDirectory:YES];
return [_dataDirectoryURL URLByAppendingPathComponent:#"Documents"];
}
Here is a link to more information http://ossh.com.au/design-and-technology/software-development/uimanageddocument-icloud-integration/