设置横屏与竖屏的方法
找到RootViewController.m这个文件，打开
找到这个方法
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// return YES for the supported orientations
// Only landscape 仅支持横向
// return ( UIInterfaceOrientationIsLandscape( interfaceOrientation ) );
// Only portrait 仅支持竖向
// return ( ! UIInterfaceOrientationIsLandscape( interfaceOrientation ) );
// All orientations 既支持竖向又支持横向
// return YES;
}