导航栏背景透明

////导航栏背景透明
    [self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
    //导航栏底部线清楚
    self.navigationController.navigationBar.barStyle = UIBarStyleBlack;
    self.navigationController.navigationBar.translucent = YES;
    [self.navigationController.navigationBar setShadowImage:[UIImage new]];

将导航设为透明后,再push跳转的页面导航栏也是透明的,该怎么改啊