设置导航栏样式以及系统返回按钮样式

- (void)customizeInterface {
    UINavigationBar *navigationBarAppearance = [UINavigationBar appearance];
    [navigationBarAppearance setTintColor:[UIColor whiteColor]];

    NSDictionary *attributes=[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],NSForegroundColorAttributeName,[UIFont boldSystemFontOfSize:18],NSFontAttributeName, nil];
    
    [navigationBarAppearance setBackgroundImage:[UIImage imageNamed:@"P_NavbgColor"] forBarMetrics:UIBarMetricsDefault];

    [navigationBarAppearance setTitleTextAttributes:attributes];
    UIBarButtonItem *
    barItemInNavigationBarAppearanceProxy = [UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil];
    //设置字体为加粗的12号系统字，自己也可以随便设置。
    [barItemInNavigationBarAppearanceProxy
     setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIFont boldSystemFontOfSize:12], NSFontAttributeName,nil] forState:UIControlStateNormal];
}