隐藏状态栏

-(void)viewWillDisappear:(BOOL)animated

{
[super viewWillDisappear:animated];
[[UIApplication sharedApplication] setStatusBarHidden:NO];

}
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[[UIApplication sharedApplication] setStatusBarHidden:YES];
}