iOS實現pdf文件預覽，上下翻頁、縮放，讀取pdf目錄

最近有個朋友想作一個pdf預覽，要求可以上下滑動翻頁、帶縮放、目錄跳轉功能。

由於以前我只作過簡單的預覽，那時直接用uiwebview實現的，此次找了下資料，發現一個比較好的庫。

其原理實現：

自定義uiview來顯示pdf+使用的是蘋果官方的api讀取目錄+uiscrollview實現縮放及翻頁。

 

不過這個庫是左右翻頁的，我不是很習慣，就改爲了上下滑動翻頁，而且在底部添加了頁碼顯示（1/10格式）。

效果圖以下：

 

 

其中幾段核心代碼：

一、加載pdf文件

CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), (__bridge CFStringRef)@"002.pdf", NULL, NULL);
    pdfDocument = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
    CFRelease(pdfURL);

 

二、獲取pdf文件目錄

#pragma mark 獲取pdf文件目錄
- (NSArray *)getPDFContents: (CGPDFDocumentRef) myDocument
{
    
    CGPDFDictionaryRef mycatalog= CGPDFDocumentGetCatalog(myDocument);
    CommentNode *rootNode = [[CommentNode alloc] initWithCatalog:mycatalog];
    CommentNode *rootOutlineNode = [rootNode childrenForName:@"/Outlines"];
    CommentNode *pagesNode = [rootNode childrenForName:@"/Pages"];
    NSArray *pagesArray = [self getPagesFromPagesNode:pagesNode];
    CommentNode *destsNode = [rootNode childrenForName:@"/Dests"];
    
    return [self getContentsForOutlineNode:rootOutlineNode pages:pagesArray destsNode:destsNode];
}

- (NSArray *)getContentsForOutlineNode:(CommentNode *)rootOutlineNode pages:(NSArray *)pagesArray destsNode:(CommentNode *)destsNode
{
    NSMutableArray *outlineArray = [[NSMutableArray alloc] init];
    CommentNode *firstOutlineNode = [rootOutlineNode childrenForName:@"/First"];
    CommentNode *outlineNode = firstOutlineNode;
    while (outlineNode) {
        NSString *title = [[outlineNode childrenForName:@"/Title"] value];
        CommentNode *destNode = [outlineNode childrenForName:@"/Dest"];
        NSMutableDictionary *outline = [NSMutableDictionary dictionaryWithDictionary:@{@"Title": title}];
        int index = 0;
        if (destNode) {
            if ([[destNode typeAsString] isEqualToString:@"Array"]) {
                CGPDFObjectRef dest = (__bridge CGPDFObjectRef)[[[destNode children] objectAtIndex:0] object];
                index = [self getIndexInPages:pagesArray forPage:dest];
            } else if ([[destNode typeAsString] isEqualToString:@"Name"]) {
                NSString *destName = [destNode value];
                CGPDFObjectRef dest = (__bridge CGPDFObjectRef)[[[[[destsNode childrenForName:destName] childrenForName:@"/D"] children] objectAtIndex:0] object];
                index = [self getIndexInPages:pagesArray forPage:dest];
            }
        } else {
            CommentNode *aNode = [outlineNode childrenForName:@"/A"];
            if (aNode) {
                CommentNode *dNode = [aNode childrenForName:@"/D"];
                if (dNode) {
                    CommentNode *d0Node = [[dNode children] objectAtIndex:0];
                    if ([[d0Node typeAsString] isEqualToString:@"Dictionary"]) {
                        CGPDFObjectRef dest = (CGPDFObjectRef)[d0Node object];
                        index = [self getIndexInPages:pagesArray forPage:dest];
                    }
                }
            }
        }
        [outline setObject:@(index) forKey:@"Index"];
        NSArray *subOutlines = [self getContentsForOutlineNode:outlineNode pages:pagesArray destsNode:destsNode];
        [outline setObject:subOutlines forKey:@"SubContents"];
        [outlineArray addObject:outline];
        outlineNode = [outlineNode childrenForName:@"/Next"];
    }
    return outlineArray;
}

- (NSArray *)getPagesFromPagesNode:(CommentNode *)pagesNode
{
    NSMutableArray *pages = [NSMutableArray new];
    CommentNode *kidsNode = [pagesNode childrenForName:@"/Kids"];
    for (CommentNode *node in [kidsNode children]) {
        NSString *type = [[node childrenForName:@"/Type"] value];
        if ([type isEqualToString:@"/Pages"]) {
            NSArray *kidsPages = [self getPagesFromPagesNode:node];
            [pages addObjectsFromArray:kidsPages];
        } else {
            [pages addObject:node];
        }
    }
    return pages;
}

- (int)getIndexInPages:(NSArray *)pages forPage:(CGPDFObjectRef)page
{
    for (int k = 0; k < pages.count; k++) {
        CommentNode *node = [pages objectAtIndex:k];
        if ([node object] == page)
            return k+1;
    }
    return 1;
}

 

源碼獲取：https://github.com/TangledHusky/YJ-PDFReader/tree/master

 

特別鳴謝：

參考文獻：https://blog.csdn.net/shenshucong520/article/details/51578695