- (void)viewWillAppear:(BOOL)animated{//设置导航栏背景图片为一个空的image，这样就透明了[self.navigationController.navigationBar setBackgroundImage:[[UIImagealloc] init] forBarMetrics:UIBarMetricsDefault];//去掉透明后导航栏下边的黑边[self.navigationController.navigationBar setShadowImage:[[UIImagealloc] init]];}
- (void)viewWillDisappear:(BOOL)animated{// 如果不想让其他页面的导航栏变为透明 需要重置[self.navigationController.navigationBar setBackgroundImage:nilforBarMetrics:UIBarMetricsDefault]; [self.navigationController.navigationBar setShadowImage:nil];}