iOS: Objective-C - having trouble previewing attachment files (QLPreviewController, UIDocumentInteractionController, and UIWebView.)

I am trying to preview an attachment (word, doc, or pdf) in a view controller. When a place attachment is selected, PlaceAttachment_ViewController should be called and display/preview the selected place attachment. This is working on iPhone 11 and 13 but not iPhone 7 or 8, running iOS 15.5.

I have tried using the following approaches to preview an attachment file: QLPreviewController, UIDocumentInteractionController, and UIWebView.

Here is sample code that I used for each of those:

QLPreviewController:

QLPreviewController* ql = [QLPreviewController new];

ql.dataSource = self;

ql.delegate = self;

// [self.navigationController pushViewController:ql animated:TRUE];

ql.currentPreviewItemIndex = 0;

 [self presentViewController:ql animated:NO completion:nil];

- (BOOL)previewController:(QLPreviewController *)controller shouldOpenURL:(NSURL *)url forPreviewItem:(id <QLPreviewItem>)item {

  return YES;

}

- (NSInteger) numberOfPreviewItemsInPreviewController: (QLPreviewController 😉 controller {

  return 1;

}

- (id <QLPreviewItem>) previewController: (QLPreviewController 😉 controller previewItemAtIndex: (NSInteger) index {

  NSString *filePath = [[MetrixPublicCache instance] getItem:@"filePath"];

  NSString *fileExtension = [[MetrixPublicCache instance] getItem:@"fileExtension"];

  NSString *fullFilePath = [@"file://" stringByAppendingString: filePath];

  NSString* test = @"/Users/sybaus/Library/Developer/CoreSimulator/Devices/ACFA5AE2-EB97-4F35-920A-C52132308569/data/Containers/Data/Application/D928D9C0-F2DF-4353-B3F2-2DA63E9FC067/Documents/attachments/20833%20Chattanooga,%20TN%201%20Feb%202016%20-%20106609-02,%20RevB%20Acoustical%20Measurements.xls";

  // NSURL *testURL = [[NSURL alloc] initFileURLWithPath:filePath];

   NSString *path = [[NSBundle mainBundle] pathForResource:filePath ofType:fileExtension];

  NSURL *url = [NSURL fileURLWithPath:path];

   return url;

  // NSString *filePath = [NSString stringWithFormat:@"%@/%@",[[MetrixAttachmentManager sharedMetrixAttachmentManager] getAttachmentPath], attachmentName];

// return [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:filePath ofType:fileExtension]];

  // return [NSURL fileURLWithPath:path];

}

Using QLPreviewController gives me the following error:

Exception    NSException *    "*** -[NSURL initFileURLWithPath:]: nil string parameter"    0x000060000365eb80

UIDocumentInteractionController:

// Initialize Document Interaction Controller

self.controller = [UIDocumentInteractionController interactionControllerWithURL:URL];

 // Configure Document Interaction Controller

 [self.controller setDelegate:self];

// Preview PDF

[self.controller presentPreviewAnimated:YES];

- (UIViewController *)documentInteractionControllerViewControllerForPreview:(UIDocumentInteractionController *)controller {

    return self;

}

- (void)documentInteractionController:(UIDocumentInteractionController *)controller willBeginSendingToApplication:(NSString *)application {

    NSLog(@"Starting to send this puppy to %@", application);

}

- (void)documentInteractionController:(UIDocumentInteractionController *)controller didEndSendingToApplication:(NSString *)application {

    NSLog(@"We're done sending the document.");

}

This gives me the following error:

Exception    NSException *    "*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[2]"    0x000060000204e2b0

UIWebView:

    NSURL *targetURL = [NSURL URLWithString: urlTextEscaped]; // only returns url if I pass in urlTextEscaped

                 NSURLRequest *request = [NSURLRequest requestWithURL:targetURL];

                 self.mywebview.scalesPageToFit = YES;

                 [self.mywebview loadRequest:request];

This will result in a blank screen being loaded instead of the attached file. See screenshot below:

I am calling the following methods to display PlaceAttachment_ViewController:

        [MetrixActivityHelper startNewViewControllerByName:self newViewControllerName:@"PlaceAttachment_ViewController"];

        PlaceAttachment_ViewController *vc = [[PlaceAttachment_ViewController alloc] init];

        [vc.navigationItem setTitle:nav_title];

        vc.attachmentQuery = attachmentQuery;

        [MetrixActivityHelper startNewViewControllerAndFinish:self newViewController:vc];

Any suggestions on resolving this issue?