objective-c - PSPDFKit がエラー「documentRef is nil , cannot get pageRef」を出すのに時間がかかる

Question

私はこのコードを使用しました：

NSURL *documentURL= [NSURL fileURLWithPath:aStrPrintPdfPath isDirectory:NO];
PSPDFDocument *document = [PSPDFDocument documentWithURL:documentURL];

PSPDFViewController *pdfController = [[PSPDFViewController alloc] initWithDocument:document];
pdfController.pageTransition = PSPDFPageTransitionCurl;
pdfController.renderingMode = PSPDFPageRenderingModeFullPageBlocking;
[pdfController setUpdateSettingsForRotationBlock:^(PSPDFViewController *aPDFController, UIInterfaceOrientation toInterfaceOrientation) {
    // conditionally set depending on rotation
    if (UIInterfaceOrientationIsLandscape(toInterfaceOrientation)) {
        aPDFController.pageMode = PSPDFPageModeDouble;
    }  else {
        aPDFController.pageMode = PSPDFPageModeSingle;
    }

}];

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:pdfController];
[self presentViewController:navController animated:YES completion:NULL];
pdfController.title = @"";
[pdfController release];
[navController release];

エラー: NSError *PSPDFError(NSInteger, NSString *_ strong problem, NSError * _autoreleasing *)/35 Error 210: for page 1.そして、30 to 50 secondsdocumentRef is nil; cannot get pageRefhanging my UI completetlyopenspdfControllernothing