view即将显示的时候，view消失的时候

- (void)viewWillAppear: (BOOL)animated

{

[super viewWillAppear:animated];

self.tabBarController.tabBar.hidden = YES;

}

- (void)viewWillDisappear: (BOOL)animated

{

[super viewWillDisappear:animated];

self.tabBarController.tabBar.hidden = NO;

}