修改导航条的背景色和下面view的一样，并隐藏黑色的线

[self.navigationController.navigationBarsetBackgroundImage:[[UIImagealloc]init]forBarMetrics:UIBarMetricsDefault];

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

[self.navigationController.navigationBarsetBackgroundColor:[UIColorcolorWithRed:0green:184/255.0blue:183/255.0alpha:1]];

self.navigationController.navigationBar.translucent=YES;

//这一句很重要

- (void)viewWillAppear:(BOOL)animated{

self.navigationController.navigationBar.translucent=NO;

}