“ [[[NSBundle mainBundle] objectForInfoDictionaryKey：]”有时返回nil

Question

I'm trying to retrieve some URLs from the infoDictionary . 9 times out of 10, the URLs are returned correctly. However, very occasionally, the URLs will return nil. Any idea what might be causing this behavior?

[NSBundle mainBundle] and [[NSBundle mainBundle] infoDictionary] are both not nil when this strange behavior occurs. Only the URLs return nil.

Answer 1

In iOS it is not possible to write to the app bundle so trying to do so will fail. Typically data is written to and read from a file in the app's document directory which can be obtained as follows:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths firstObject];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:myFileName];