IOS7 system View Height has been 480 (upper and lower part of the black screen)

Today encountered a wonderful problem, that is, in iOS7 above the system operation, through

UIScreen *screen = [UIScreen mainscreen];

CGRect rect = [screen bounds];

The screen height obtained is 480.

Tangled for a long time, the Internet to check the next, Http://blog.csdn.net/wsk_123_123/article/details/24969975 said is the project to start the cause of the picture,

Then go to the project start picture set up, sure enough, but this is why? I don't think I understand.

IOS7 system View Height has been 480 (upper and lower part of the black screen)