我能够使用以下代码解决我的问题：）

I was able to solve my issue using this line of code :)

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSArray *pdfs = [[NSBundle bundleWithPath:[paths objectAtIndex:0]] pathsForResourcesOfType:@"pdf" inDirectory:nil];