-(void)viewWillAppear:(BOOL)animated{

    [superviewWillAppear:animated];

    //防止push的时候动画过渡不自然

    [self.navigationController setNavigationBarHidden:YES animated:animated];

}

-(void)viewWillDisappear:(BOOL)animated{

    [superviewWillDisappear:animated];

   //防止push的时候动画过渡不自然

    [self.navigationController setNavigationBarHidden:NO animated:animated];

}