index 0 beyond bounds for empty array while getting to the documents directory

问题

I use the following code to get to the documents directory.

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

Why would my app be crashing with the following message?

*** -[__NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array

I can't see how my NSArray (immutable array) can be empty. The function is supposed to return the documents folder in an array. Any ideas?

回答1:

1) Are you sure the crash is there?

2) Not totally related but can help.

回答2:

The array returned by NSSearchPathForDirectoriesInDomains has zero elements in it. It's empty. Exactly what the error message says.

回答3:

Not answering why, but since Xcode 5:

NSString *documentsDirectory = [paths firstObject];

If it's empty, it won't raise an exception, it will return nil. No crash.

回答4:

Try using NSHomeDirectory() instead... It is a nicer way to get the applications home directory.

Note: If you are after the Documents Directory then you may need to append @"Documents/" to the string

来源：https://stackoverflow.com/questions/12938962/index-0-beyond-bounds-for-empty-array-while-getting-to-the-documents-directory