当我尝试打印当前屏幕截图(对于iPad视图)时,我在控制台窗口中遇到这个奇怪的错误：
找不到PDF标题：找不到％PDF.
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.
解决方法
这将有助于知道哪条线确切地导致控制台输出.您可以在调试器中单步执行以查找.
我的猜测是调用 – [UIPrintInteractionController canPrintData：].如果您阅读the documentation for that method,您将看到它必须检查该数据是否包含PDF.它看起来像尝试和失败,沿途打印一条消息.