iOS设置导航栏渐变颜色

桃扇骨 2023-10-17 15:13 62阅读 0赞

[Demo下载地址][Demo]

之前也写过一篇关于导航渐变的博客，链接地址如下：

[http://blog.csdn.net/minggeqingchun/article/details/52571810][http_blog.csdn.net_minggeqingchun_article_details_52571810]

但是这篇博客所写的文章和目前这篇原理差不多，都是在滑动时，根据滑动的Y值改变去改变导航颜色的alpha值，但是测试多次发现还是偶尔会浮现一些bug出来，因此优化了一下直接给UINavigationBar增加分类

- (void)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 insertSubview:self.overlay atIndex:0];
            
            //去掉一横线
            if ([self respondsToSelector:@selector( setBackgroundImage:forBarMetrics:)]){
                NSArray *list = self.subviews;
                for (id obj in list) {
                    if ([obj isKindOfClass:[UIImageView class]]) {
                        UIImageView *imageView=(UIImageView *)obj;
                        NSArray *list2=imageView.subviews;
                        for (id obj2 in list2) {
                            if ([obj2 isKindOfClass:[UIImageView class]]) {
                                UIImageView *imageView2=(UIImageView *)obj2;
                                imageView2.hidden=YES;
                            }
                        }
                    }
                }
            }
        }
        self.overlay.backgroundColor = backgroundColor;
    }

![Center][]

[Demo]: https://github.com/RookieForMingge/NavigationAlpha
[http_blog.csdn.net_minggeqingchun_article_details_52571810]: http://blog.csdn.net/minggeqingchun/article/details/52571810
[Center]: https://img-blog.csdn.net/20170819104345932?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvTWluZ2dlUWluZ2NodW4=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center