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

    NSMutableDictionary *attrs = [NSMutableDictionary dictionary];

    attrs[NSForegroundColorAttributeName] = [UIColor whiteColor];

    attrs[NSFontAttributeName] = [UIFont systemFontOfSize:17];

    [self.navigationController.navigationBar setTitleTextAttributes:attrs];

 UIBarButtonItem *leftItem = [[UIBarButtonItem alloc] initWithTitle:@"left" style:UIBarButtonItemStylePlain target:self action:@selector(left)];

  self.navigationItem.leftBarButtonItem = leftItem;

  UIBarButtonItem *rightItem = [[UIBarButtonItem alloc] initWithTitle:@"right" style:UIBarButtonItemStylePlain target:self action:@selector(right)];   

    self.navigationItem.rightBarButtonItem = rightItem;

 self.navigationController.navigationBar.tintColor = [UIColor redColor];如果要不同item不同顏色，那么item要帶一個自定義按鈕，在設置按鈕屬性

    UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:self action:@selector(back)];

 self.navigationItem.backBarButtonItem = backItem;

 self.view.backgroundColor = [UIColor greenColor];如果透明看到的就是綠色。然后在分別設置

 [self.navigationController.navigationBar setBackgroundImage:[self imageWithBgColor:[UIColor colorWithRed:1 green:1 blue:1 alpha:0]] forBarMetrics:UIBarMetricsDefault];

   [self.navigationController.navigationBar setShadowImage:[self imageWithBgColor:[UIColor colorWithRed:1 green:1 blue:1 alpha:0]]];這樣就是透明的了

如果要監聽滾動而使導航欄顏色漸變，那么可以在scrollView的代理方法中添加這樣的代碼

-(void)scrollViewDidScroll:(UIScrollView *)scrollView

{

     [self.navigationController.navigationBar setBackgroundImage:[self imageWithBgColor:[UIColor colorWithRed:1 green:0 blue:0 alpha:self.tableView.contentOffset.y / 100]] forBarMetrics:UIBarMetricsDefault];

}
這邊用的imageWithBgColor方法

-(UIImage *)imageWithBgColor:(UIColor *)color {

    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);

    UIGraphicsBeginImageContext(rect.size);

    CGContextRef context = UIGraphicsGetCurrentContext();    

    CGContextSetFillColorWithColor(context, [color CGColor]);

    CGContextFillRect(context, rect);

     UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

     return image;

}
最后大致的效果點左邊是默認顏色，點右邊透明，滾動漸變，就在這記下這些了，希望有可以幫助到的地方~~