源码在底下

前言：

该框架代码非常简单，仅需几行代码即可用于项目。 1、目前支持动态图（GIF）、静态图，未来还会支持视频、缓存、横向等。 2、页面切换时带渐变效果，体验感更强 3、支持最后一页右移消失和前面页面直接跳过 4、支持额外自定义，显示页面底下dots以及skip按钮与否。 5、更低的内存占用、CPU占用 6、支持直接使用图片名字，框架自动识别图片类型 7、支持cocopods安装以及手动拖进项目

1、使用方式：

- (UIViewController *)setupDynamicVC {
    
    DWIntrosPageContentViewController *page1 = [DWIntrosPageContentViewController introsPageWithBackgroundImageWithName:@"gif01"];
    DWIntrosPageContentViewController *page2 = [DWIntrosPageContentViewController introsPageWithBackgroundImageWithName:@"gif02"];
    DWIntrosPageContentViewController *page3 = [DWIntrosPageContentViewController introsPageWithBackgroundImageWithName:@"gif03"];
    DWIntrosPagesViewController *introsPage = [DWIntrosPagesViewController dwIntrosPagesWithPageArray:@[page1, page2, page3]];
    __weak typeof(self) weakSelf = self;
    introsPage.skipButtonClickedBlock = ^{
        NSLog(@"clicked skip button");
        [weakSelf setupHomeVC];
    };
    return introsPage;
}

上面为使用静态图方式，动态图方式与此大同小异，故不多说。

2、框架目录

该框架主要有两大类：

• DWIntrosPageContentViewController引导页的每一个详情页面
• DWIntrosPagesViewController相当于引导页的容器，承载引导页的每一个详情页面。

下面摘取部分代码 DWIntrosPageContentViewController

+ (instancetype)introsPageWithBackgroundImageWithName:(NSString *)imgName {
    if ([imgName.pathExtension isEqualToString:@"jpg"] || [imgName.pathExtension isEqualToString:@"png"]) {
        return [[self alloc] initWithBackgroundImageWithName:imgName];
    }
    NSData *data = [self gainFullImageWithName:imgName];
    if ([_imagePathExtension((__bridge CFDataRef)(data)) isEqualToString:@"GIF"]) {
        return [[self alloc] initWithBackgroundGIFWithData:data];
    }else if([_imagePathExtension((__bridge CFDataRef)(data)) isEqualToString:@"JPG"]) {
        return [[self alloc] initWithBackgroundNormalImageWithData:data];
    }
    return [[self alloc] initWithBackgroundImageWithName:imgName];
}

设置每一页的详情，不同类型不同设置方式

+ (NSData *)gainFullImageWithName:(NSString *)name {
    if (name.length == 0) return nil;
    
    NSString *res = name.stringByDeletingPathExtension;
    NSString *ext = name.pathExtension;
    NSString *path = nil;
    NSArray *exts = ext.length > 0 ? @[ext] : @[@"", @"png", @"jpeg", @"jpg", @"gif", @"webp", @"apng"];
    for (NSString *e in exts) {
        path = [[NSBundle mainBundle] pathForResource:res ofType:e];
        if (path) break;
    }
    NSData *data = [NSData dataWithContentsOfFile:path];
    if (data.length == 0) return nil;
    return data;

}

判断图片是否有后缀，有后缀直接使用，没有后缀则尝试加上后缀名去[NSBundle mainBundle]寻找

DWIntrosPagesViewController

#pragma mark ------ UIPageViewControllerDelegate && DataSource ------
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController {
   
    if (viewController == [self.viewControllers firstObject]) {
        return nil; // Return 'nil' to indicate that no more progress can be made in the given direction. （表示已经不能继续往左）
    }else {
        NSInteger lastPageIndex = [self.viewControllers indexOfObject:viewController] - 1;
        NSLog(@"%ld", (long)lastPageIndex);
        return [self.viewControllers objectAtIndex:lastPageIndex];
    }
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {
    if (viewController == [self.viewControllers lastObject]) {
        return nil; // (表示已经不能继续往右）
    }else {
        NSInteger nextPageIndex = [self.viewControllers indexOfObject:viewController] + 1;
//        NSLog(@"%ld", (long)nextPageIndex);
        return self.viewControllers[nextPageIndex];
    }
}

判断控制器数组中的控制器，如果是首页或者尾页，则返回nil

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers transitionCompleted:(BOOL)completed {
    // We need to confirm the transition completed and to do other things.
    // 确保转换完成才改变底下的小圆点
    if (completed) {
        _currentPage = [pageViewController.viewControllers lastObject];
        NSInteger currentIndex = [self.viewControllers indexOfObject:_currentPage];
        [self.pageControl setCurrentPage:currentIndex];
    }
}

等页面切换完成后才切换底下的dots

#pragma mark ------ changeAlpha ------
- (void)changeAlphaWithRatio:(CGFloat)ratio scrollView:(UIScrollView *)scrollView {

    if (ratio == 0) {
        return;
    }
   
    // figure out alpha
    // next page alpha equals to the ratio
    CGFloat nextPageAlpha = ratio;
    CGFloat currentPageAlpha = 1 - ratio;
    
    // warning: don't mix up the order of the two sentences
    //注意： 不要弄乱下面两句顺序
    [self.nextPage updateAlpha:nextPageAlpha];
    [self.currentPage updateAlpha:currentPageAlpha];
    
    // change the alpha of skip button and pageControl dots
    if (_nextPage == [self.viewControllers lastObject] ) {
        self.skipButton.alpha = currentPageAlpha;
        self.pageControl.alpha = currentPageAlpha;
    }
    if (_currentPage == [self.viewControllers lastObject]) {
        self.skipButton.alpha = nextPageAlpha;
        self.pageControl.alpha = nextPageAlpha;
        // The last page will not show the skill button and page dots.
        // 最后一页往右也不能出现下面两个按钮
        if ((scrollView.contentOffset.x > self.historyX)) {
            self.skipButton.alpha = 0;
            self.pageControl.alpha = 0;
            if (scrollView.contentOffset.x - self.historyX > 45) {
                [self skipButtonCliked];
            }
        }
    }

}

根据移动的偏移值，对切换中的前后两个页面进行透明度的改变，从而达到渐变效果。

最后

整体而言，代码非常简单，请各位大佬轻拍。

代码地址