[iOS] transparent navigation bar

transparentNavigationBar.m

UINavigationController *tempNavCont = [[UINavigationController alloc] initWithRootViewController:tempVC];
[tempNavCont.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
tempNavCont.navigationBar.shadowImage = [UIImage new];
tempNavCont.navigationBar.translucent = YES;
tempNavCont.view.backgroundColor = [UIColor clearColor];
tempNavCont.navigationBar.backgroundColor = [UIColor clearColor];