iphone – 控制台错误：找不到PDF标题：找不到`％PDF’

我想知道为什么在控制台窗口中触发此错误？为什么它提到了与PDF相关的东西,虽然我没有在整个项目中使用任何PDF相关的东西.

用于打印屏幕截图的代码是：

- (IBAction)print:(id)sender {

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
        UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,NO,[UIScreen mainScreen].scale);
     else
         UIGraphicsBeginImageContext(self.view.bounds.size);

     [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

     UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

     UIGraphicsEndImageContext();


    //saving the file to documents directory

     NSData * imageData = UIImagePNGRepresentation(viewImage);
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
     NSString *documentsDirectory = [paths objectAtIndex:0];
     documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@"Screenshot.png"];
     [imageData writeToFile:documentsDirectory atomically:YES];

     NSString *myFilePath = [documentsDirectory stringByAppendingPathComponent:@"Screenshot.png"];
    UIImage *screenShot = [UIImage imageWithData:imageData];
    NSData *myData = [NSData dataWithData:UIImagePNGRepresentation(screenShot)];

     self.pic = [UIPrintInteractionController sharedPrintController];
      if (self.pic && [UIPrintInteractionController canPrintData:myData] ) {

         self.pic.delegate = self;

        //filling up print info
         UIPrintInfo *printInfo = [UIPrintInfo printInfo];
         printInfo.outputType = UIPrintInfoOutputGeneral;
         printInfo.jobName = [myFilePath lastPathComponent];
         printInfo.duplex = UIPrintInfoDuplexLongEdge;
         self.pic.printInfo = printInfo;

         self.pic.showsPageRange = YES;
         self.pic.printingItem = myData;

        void (^completionHandler)(UIPrintInteractionController *,BOOL,NSError *) =
         ^(UIPrintInteractionController *pic,BOOL completed,NSError *error) {

             if (!completed && error)
                 NSLog(@"FAILED! due to error in domain %@ with error code %u",error.domain,error.code);
             };

        [self.pic presentFromRect:self.printButton.frame inView:self.view animated:YES completionHandler: completionHandler];    // iPad


        }

    }

文件路径(Screenshot.png)是正确的,并且它已正确保存到文档目录.