最近有个朋友想做一个pdf预览，要求能够上下滑动翻页、带缩放、目录跳转功能。

因为之前我只做过简单的预览，那时直接用uiwebview实现的，这次找了下资料，发现一个比较好的库。

其原理实现：

自定义uiview来显示pdf+使用的是苹果官方的api读取目录+uiscrollview实现缩放及翻页。

 

不过这个库是左右翻页的，我不是很习惯，就改成了上下滑动翻页，并且在底部添加了页码显示（1/10格式）。

效果图如下：

 

 

其中几段核心代码：

1、加载pdf文件

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

 

2、获取pdf文件目录

#pragma mark 获取pdf文件目录- (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;}

 

源码获取：

 

特别鸣谢：

参考文献：https://blog.csdn.net/shenshucong520/article/details/51578695