将navigationBar全透明,并去掉底部黑线

1.3333.png代表全透明图片

[self.navigationController.navigationBarsetBackgroundImage:[UIImageimageNamed:@"3333.png"]forBarMetrics:UIBarMetricsDefault];

self.navigationController.navigationBar.barStyle=UIBarStyleBlackTranslucent;

[self.navigationController.navigationBarsetShadowImage:[[UIImagealloc]init]];