App crashes when exporting as PDF on iPad

• Bug report: https://forum.inkdrop.app/t/pdf-export-crashes-inkdrop-on-ipad/4279

Exception

Exception	NSException *	"UIPopoverPresentationController (<UIPopoverPresentationController: 0x1611467a0>) should have a non-nil sourceView or barButtonItem set before the presentation occurs."	0x0000600000e3d740

Solutions

• How to present UIActivityViewController on iPhone and iPad | by Dushyant Bansal | Medium

  The error message is self explanatory. UIActivityViewController is presented in a popover on iPad. Even documentations mentions this

  On iPad, you must present the view controller in a popover.
  

  Therefore, on iPad, you must configure popoverPresentationController by providing either a sourceView and sourceRect or a barButtonItem.

It works!

diff --git a/ios/Inkdrop/PDFExporter.m b/ios/Inkdrop/PDFExporter.m
index 8a2047a..2115ae6 100644
--- a/ios/Inkdrop/PDFExporter.m
+++ b/ios/Inkdrop/PDFExporter.m
@@ -37,6 +37,11 @@ RCT_EXPORT_METHOD(exportAsPDF:(NSString* __nonnull)title
           UIActivityViewController* activityViewController = [[UIActivityViewController alloc] initWithActivityItems:dataToShare applicationActivities:nil];
           if (activityViewController != nil) {
             AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
+            if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
+              CGRect screenRect = [[UIScreen mainScreen] bounds];
+              activityViewController.popoverPresentationController.sourceView = delegate.window.rootViewController.view;
+              activityViewController.popoverPresentationController.sourceRect = CGRectMake(screenRect.size.width / 2, screenRect.size.height, 10, 10);
+            }
             [delegate.window.rootViewController presentViewController:activityViewController animated:YES completion:^() {
             }];
           }

• Commit: https://github.com/inkdropapp/xxxxxx/commit/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx