ios7适配--隐藏status bar

//viewDidload
if ([self respondsToSelector:@selector(setNeedsStatusBarAppearanceUpdate)]) {
// iOS 7
[self prefersStatusBarHidden];
[self performSelector:@selector(setNeedsStatusBarAppearanceUpdate)];
} else {
// iOS 6
[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationSlide];
}

// Add this Method
- (BOOL)prefersStatusBarHidden
{
return YES;
}