在某个需要改变navi上面控件属性的vc

#pragma mark - 视图即将出现
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];

self.navigationController.navigationBar.barTintColor = [UIColor whiteColor];

NSDictionary *dic = @{
                      NSForegroundColorAttributeName:kRGBColor(51, 51, 51),
                      NSFontAttributeName:[UIFont systemFontOfSize:16 * SCALE_WIDTH]
                      };
self.navigationController.navigationBar.titleTextAttributes = dic;

//按钮颜色
self.navigationController.navigationBar.tintColor = kRGBColor(51, 51, 51);

}

#pragma mark - 视图即将消失
- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];

self.navigationController.navigationBar.barTintColor = kRGBColor(41, 148, 231);
NSDictionary *dic = @{
                      NSForegroundColorAttributeName:[UIColor whiteColor],
                      NSFontAttributeName:[UIFont systemFontOfSize:16 * SCALE_WIDTH]
                      };
self.navigationController.navigationBar.titleTextAttributes = dic;
//按钮颜色
self.navigationController.navigationBar.tintColor = [UIColor whiteColor];
}