不知道原来作者去什么地方了，现在显示不出来的可以这样解决的 about ltnavigationbar

[langhua9527]

`- (void)lt_setBackgroundColor:(UIColor *)backgroundColor
{
if (!self.overlay) {
[self setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
self.overlay = [[UIView alloc] initWithFrame:CGRectMake(0, -20, [UIScreen mainScreen].bounds.size.width, CGRectGetHeight(self.bounds) + 20)];
self.overlay.userInteractionEnabled = NO;
self.overlay.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
}

self.overlay.backgroundColor = backgroundColor;
dispatch_async(dispatch_get_main_queue(), ^{
    [self insertSubview:self.overlay atIndex:0];
});

}`

just try it , i fix it

[yhjiang]

- (void)lt_setBackgroundColor:(UIColor *)backgroundColor
{
    if (!self.overlay) {
        [self setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
        self.overlay = [[UIView alloc] initWithFrame:CGRectMake(0, -20, [UIScreen mainScreen].bounds.size.width, CGRectGetHeight(self.bounds) + 20)];
        self.overlay.userInteractionEnabled = NO;
        self.overlay.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
    }
    self.overlay.backgroundColor = backgroundColor;
    dispatch_async(dispatch_get_main_queue(), ^{
        [self insertSubview:self.overlay atIndex:0];
    });
}

楼上的这个方法亲测可以解决，我iOS10.2系统 xcode8.2跑的