直接上代码了：
写在父类UINavigationController中的
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
if (@available(iOS 11.0, *)) {
//关键适配
UIImage *backButtonImage = [[UIImage imageNamed:@"nav_arrow"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
self.navigationBar.backIndicatorImage = backButtonImage;
self.navigationBar.backIndicatorTransitionMaskImage = backButtonImage;
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(-kScreenWidth, 0)forBarMetrics:UIBarMetricsDefault];//UIOffsetMake(-kScreenWidth, 0)zh只要横向偏移，纵向偏移返回图标也会偏移
}
else{
//设置返回按钮的图片
UIImage *backButtonImage = [[UIImage imageNamed:@"nav_arrow"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 30, 0, 0)];
[[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
//将返回按钮的文字position设置不在屏幕上显示
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(-kScreenWidth, -kScreenHeight)forBarMetrics:UIBarMetricsDefault];
}
if (self.childViewControllers.count > 0) {
//哥么你要想隐藏.那么必须在我push之前给我设置
viewController.hidesBottomBarWhenPushed = YES;
}
//调用父类的方法
[super pushViewController:viewController animated:animated];
}
-(void)back
{
[self popViewControllerAnimated:YES];
}
