DWIntrosPage 簡單定製引導頁

前言：

該框架代碼很是簡單，僅需幾行代碼便可用於項目。 一、目前支持動態圖（GIF）、靜態圖，將來還會支持視頻、緩存、橫向等。 二、頁面切換時帶漸變效果，體驗感更強 三、支持最後一頁右移消失和前面頁面直接跳過 四、支持額外自定義，顯示頁面底下dots以及skip按鈕與否。 五、更低的內存佔用、CPU佔用 六、支持直接使用圖片名字，框架自動識別圖片類型 七、支持cocopods安裝以及手動拖進項目

一、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;
}
複製代碼

上面爲使用靜態圖方式，動態圖方式與此大同小異，故很少說。

二、框架目錄

該框架主要有兩大類：

• DWIntrosPageContentViewController引導頁的每個詳情頁面
• DWIntrosPagesViewController至關於引導頁的容器，承載引導頁的每個詳情頁面。

下面摘取部分代碼 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];
}
複製代碼

設置每一頁的詳情，不一樣類型不一樣設置方式

+ (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;

}
複製代碼

判斷圖片是否有後綴，有後綴直接使用，沒有後綴則嘗試加上後綴名去[NSBundle mainBundle]尋找

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. （表示已經不能繼續往左）
    }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; // (表示已經不能繼續往右）
    }else {
        NSInteger nextPageIndex = [self.viewControllers indexOfObject:viewController] + 1;
//        NSLog(@"%ld", (long)nextPageIndex);
        return self.viewControllers[nextPageIndex];
    }
}
複製代碼

判斷控制器數組中的控制器，若是是首頁或者尾頁，則返回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.
    // 確保轉換完成才改變底下的小圓點
    if (completed) {
        _currentPage = [pageViewController.viewControllers lastObject];
        NSInteger currentIndex = [self.viewControllers indexOfObject:_currentPage];
        [self.pageControl setCurrentPage:currentIndex];
    }
}
複製代碼

等頁面切換完成後才切換底下的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： 不要弄亂下面兩句順序 [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. // 最後一頁往右也不能出現下面兩個按鈕 if ((scrollView.contentOffset.x > self.historyX)) { self.skipButton.alpha = 0; self.pageControl.alpha = 0; if (scrollView.contentOffset.x - self.historyX > 45) { [self skipButtonCliked]; } } } } 複製代碼

根據移動的偏移值，對切換中的先後兩個頁面進行透明度的改變，從而達到漸變效果。

最後

總體而言，代碼很是簡單，請各位大佬輕拍。

代碼地址