UIDocumentPickerViewController copied files disappear on download to test iPad - ipad

Question

I am using UIDocumentPickerViewController to allow the user to select files that will be "attached" and available within the App. The concept is allow the user to send detail via email with the selected file attachments.
As each file is attached, I copy the file from the tmp Inbox (where fileManager puts the imported file) to a directory I create within the App document directory called "fileAttachments".
I list the files in a UITableView and the user can select each entry and preview the content within a QLPreviewController view using the path stored in the file object fileOJ.filePath.
It all works swimmingly well, until a reload of the project down to my test iPad, then all the files seem to disappear. My list of the files is still fine, but there is no file at the path location.
Any help with just what is happenning would be greatly appreciated.
- (IBAction)selectFilesAction:(UIBarButtonItem *)sender {
NSArray *UTIs = [NSArray arrayWithObjects:#"public.data", nil];
[self openFilePicker:UTIs];
}
- (void)openFilePicker:(NSArray *)UTIs {
UIDocumentPickerViewController *documentPicker = [[UIDocumentPickerViewController alloc] initWithDocumentTypes:UTIs inMode:UIDocumentPickerModeImport];
documentPicker.delegate = self;
documentPicker.allowsMultipleSelection = FALSE;
documentPicker.popoverPresentationController.barButtonItem = self.selectFilesButton;
[self presentViewController:documentPicker animated:TRUE completion:nil];
}
- (void)documentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(NSArray <NSURL *>*)urls {
NSLog(#"picked URLs %#", urls);
// selecting multiple documents is cool, but requires iOS 11
for (NSURL *documentURL in urls) {
//get file details
NSDictionary *attr = [documentURL resourceValuesForKeys:#[NSURLFileSizeKey,NSURLCreationDateKey] error:nil];
NSLog(#"object: %#", attr);
NSNumber *fileSize = [attr valueForKey:NSURLFileSizeKey];
NSDate *dateFileCreated = [attr valueForKey:NSURLCreationDateKey];
NSDateFormatter *storageDateFormat = [[NSDateFormatter alloc] init];
[storageDateFormat setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSString *createdDateString = [storageDateFormat stringFromDate:dateFileCreated];
MMfile *fileObj = [[MMfile alloc]init];
fileObj.fileName = documentURL.lastPathComponent;
fileObj.meetingID = _meetingID;
fileObj.fileSize = fileSize;
fileObj.fileCreateDate = createdDateString;
//move file to new directory
fileObj.filePath = [self movefile:documentURL.lastPathComponent sourceFilePath:documentURL.path directory:#"fileAttachments"];
//save file details
[self.meetingModel saveFile:fileObj];
//refresh array and reload table
self.fileArray = [self.meetingModel getFiles:self.meetingID];
[self.tableView reloadData];
}
}
- (void)documentPickerWasCancelled:(UIDocumentPickerViewController *)controller {
NSLog(#"cancelled");
}
-(NSString *)movefile:(NSString *)filename sourceFilePath:(NSString *)sourcePath directory:(NSString *)directoryName{
// Move file from tmp Inbox to the destination directory
BOOL isDir;
NSError *error;
NSFileManager *fileManager= [NSFileManager defaultManager];
//get directory path
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString* directoryPath;
if (paths>0) {
NSString *documentsDirectory = [paths objectAtIndex:0];
directoryPath = [NSString stringWithFormat:#"%#/%#",documentsDirectory,directoryName];
}
if(![fileManager fileExistsAtPath:directoryPath isDirectory:&isDir])
if(![fileManager createDirectoryAtPath:directoryPath withIntermediateDirectories:NO attributes:nil error:NULL])
NSLog(#"Error: Create folder failed %#", directoryPath);
NSString *destinationPath = [NSString stringWithFormat:#"%#/%#",directoryPath,filename];;
BOOL success = [fileManager moveItemAtPath:sourcePath toPath:destinationPath error:&error];
if (success) {
NSLog(#"moved file");
}else{
NSLog(#"error %#",error.description);
}
return destinationPath;
}

Answer 1

Found the issue. When the project is rebuilt and downloaded to the iPad the AppID changes, and as the documents path includes the AppID, so the documents path changes. Key is not to save the file path, only the file name and rebuild the path each instance. After having found the issue, I now see other similar posts I didn't find earlier. Also see Document directory path change when rebuild application