导航栏和页面融合的渐变色

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我是靠谱客的博主尊敬魔镜，最近开发中收集的这篇文章主要介绍导航栏和页面融合的渐变色，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (scrollView == self.mainTableView) {//滚动距离判定
        if (scrollView.contentOffset.y > 135) {
            self.title = @"书籍详情";
            [self changeStatusBarColorToDark:NO];
            self.shareButton.selected = YES;
            [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@""]
                                                          forBarMetrics:UIBarMetricsDefault];
        }else {
            self.title = @"";
            self.shareButton.selected = NO;
            [self changeStatusBarColorToDark:YES];
            [self.navigationController.navigationBar setBackgroundImage:self.statusBarImage
                                                          forBarMetrics:UIBarMetricsDefault];
        }

        if (scrollView.contentOffset.y > 0 && scrollView.contentOffset.y < 135) {
            self.backgroundImg.frame = CGRectMake(0, -scrollView.contentOffset.y, SWIDTH, 135);
        }
    }
}

- (void)changeStatusBarColorToDark:(BOOL)dark {
    [[NSNotificationCenter defaultCenter] postNotificationName:kChangeStatusBarColorNotificatonName
                                                        object:nil
                                                      userInfo:@{@"dark":@(dark)}];
}

//导航栏图片
- (void)statusBarSetImage:(UIImage *)img {
    UIImage *orgImage = [img applyBlurWithRadius:25 tintColor:[UIColor colorWithWhite:1 alpha:0.6] saturationDeltaFactor:1.8 maskImage:nil];
    UIImage *clipImg = [orgImage clipWithImageRect:CGRectMake(100, 0, SWIDTH, 64)];
    clipImg = [clipImg resizableImageWithCapInsets:UIEdgeInsetsZero resizingMode:UIImageResizingModeStretch];
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.navigationController.navigationBar setBackgroundImage:clipImg
                                                      forBarMetrics:UIBarMetricsDefault];
        self.backgroundImg.image = [orgImage clipWithImageRect:CGRectMake(100, 64, SWIDTH, 135)];


    });
    self.statusBarImage = clipImg;
}

//渐变layer
- (void)insertTransparentGradient {
    UIColor *colorOne = [UIColor colorWithWhite:1.0 alpha:0.0];
    UIColor *colormid = [UIColor colorWithWhite:1.0 alpha:0.1];
    UIColor *colorTwo = [UIColor colorWithWhite:1.0 alpha:1.0];
    NSArray *colors = [NSArray arrayWithObjects:(id)colorOne.CGColor,colormid.CGColor, colorTwo.CGColor, nil];
    NSNumber *stopOne = [NSNumber numberWithFloat:0.0];
    NSNumber *stopMid = [NSNumber numberWithFloat:0.3];
    NSNumber *stopTwo = [NSNumber numberWithFloat:1.0];
    NSArray *locations = [NSArray arrayWithObjects:stopOne, stopMid, stopTwo, nil];

    //crate gradient layer
    CAGradientLayer *headerLayer = [CAGradientLayer layer];

    headerLayer.colors = colors;
    headerLayer.locations = locations;
    headerLayer.frame = self.backgroundImg.bounds;
    [self.backgroundImg.layer insertSublayer:headerLayer atIndex:0];
}