这篇文章主要介绍了iOS如何实现PDF文件浏览功能，具有一定借鉴价值，感兴趣的朋友可以参考下，希望大家阅读完这篇文章之后大有收获，下面让小编带着大家一起了解一下。
创新互联技术团队10多年来致力于为客户提供网站设计、成都网站设计、成都品牌网站建设、成都全网营销推广、搜索引擎SEO优化等服务。经过多年发展，公司拥有经验丰富的技术团队，先后服务、推广了成百上千家网站，包括各类中小企业、企事单位、高校等机构单位。
iOS开发，显示PDF格式文件方法有很多：
最简单的应该是UIWebView，可以加载本地或网络PDF文件，支持上下滑动浏览、缩放。优化一点的是用系统的QLPreviewController加载，实现起来也比较方便，支持上下滑动浏览，左后滑动可多PDF文件切换，同时支持原生的分享打印，QLPreviewController支持的文档格式也比较多，如pdf、doc、docx、xls、xlsx、txt、ppt、mp4...上面两种都没有足够的自定义空间，不在这里做过多的介绍了，另外一种也就是本篇用到的iOS核心图形库：Core Graphics，绘制PDF文档。
简单说一下逻辑，根据本地路径获取到CGPDFDocumentRef，在drawRect中绘制上下文，画出PDF文件。通过UIScrollView实现缩放，添加UIGestureRecognizer实现单击、双击、左滑、右滑功能。基于CATransition实现翻页动画。
下面贴上核心代码：
承载PDF文件视图的控制器：HWPDFBrowseVC
#import @interface HWPDFBrowseVC : UIViewController@property (nonatomic, copy) NSString *filePath;@property (nonatomic, copy) NSString *fileName;@end/*** ---------------分割线--------------- ***/#import "HWPDFBrowseVC.h"#import "HWPDFBrowseView.h"#import "HWPDFBrowseToolBar.h"#import "HWPDFBrowseScrollView.h"#define KPicMaxScale 3.0#define KMainW [UIScreen mainScreen].bounds.size.width#define KMainH [UIScreen mainScreen].bounds.size.height@interface HWPDFBrowseVC ()@property (nonatomic, weak) HWPDFBrowseScrollView *scrollView;@property (nonatomic, weak) HWPDFBrowseView *browseView;@property (nonatomic, weak) HWPDFBrowseToolBar *toolBar;@property (nonatomic, assign) CGFloat minZoomScale;@property (nonatomic, assign) CGFloat lastScrContX;@end@implementation HWPDFBrowseVC- (void)viewDidLoad { [super viewDidLoad]; //初始化 self.view.backgroundColor = [UIColor whiteColor]; self.navigationItem.title = _fileName; //创建控件 [self creatControl];}- (void)viewWillDisappear:(BOOL)animated{ [super viewWillDisappear:animated]; //防止隐藏导航时，左滑返回导航消失 CGRect temNavBarFrame = self.navigationController.navigationBar.frame; temNavBarFrame.origin.y = 20; self.navigationController.navigationBar.frame = temNavBarFrame;}- (void)creatControl{ //导航右侧按钮 UIButton *deleteBtn = [[UIButton alloc] initWithFrame:CGRectMake(9, 0, 40, 40)]; deleteBtn.titleLabel.font = [UIFont systemFontOfSize:16.f]; [deleteBtn setTitle:@"跳页" forState:UIControlStateNormal]; [deleteBtn setTitleColor:[UIColor blueColor] forState:UIControlStateNormal]; [deleteBtn addTarget:self action:@selector(navBtnOnClick) forControlEvents:UIControlEventTouchUpInside]; UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)]; [rightView addSubview:deleteBtn]; self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:rightView]; //scrollView HWPDFBrowseScrollView *scrollView = [[HWPDFBrowseScrollView alloc] initWithFrame:[UIScreen mainScreen].bounds]; scrollView.delegate = self; scrollView.backgroundColor = [UIColor blackColor]; scrollView.maximumZoomScale = KPicMaxScale; scrollView.showsVerticalScrollIndicator = NO; scrollView.showsHorizontalScrollIndicator = NO; [self.view addSubview:scrollView]; _scrollView = scrollView; //pdf视图 HWPDFBrowseView *browseView = [[HWPDFBrowseView alloc] initWithFilePath:_filePath]; [scrollView addSubview:browseView]; _browseView = browseView; //绘制pdf视图后缩放至屏幕完全居中显示 CGRect frame = browseView.frame; frame.size.width = browseView.frame.size.width > KMainW ? KMainW : browseView.frame.size.width; frame.size.height = frame.size.width * (browseView.frame.size.height / browseView.frame.size.width); if (frame.size.height > KMainH) { frame.size.height = KMainH; frame.size.width = KMainH * (browseView.frame.size.width / browseView.frame.size.height); } //根据缩放调整 _minZoomScale = frame.size.width / browseView.frame.size.width; scrollView.allowScrollScale = _minZoomScale; scrollView.minimumZoomScale = _minZoomScale; scrollView.zoomScale = _minZoomScale; //底部工具栏 HWPDFBrowseToolBar *toolBar = [[HWPDFBrowseToolBar alloc] initWithFrame:CGRectMake(0, KMainH - 49, KMainW, 49) currentPage:_browseView.currentPage totalPage:_browseView.totalPages]; toolBar.delegate = self; [self.view addSubview:toolBar]; _toolBar = toolBar; //单击 UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(click)]; tap.numberOfTouchesRequired = 1; tap.numberOfTapsRequired = 1; [scrollView addGestureRecognizer:tap]; //双击 UITapGestureRecognizer *tapDouble = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleClick)]; tapDouble.numberOfTapsRequired = 2; [scrollView addGestureRecognizer:tapDouble]; [tap requireGestureRecognizerToFail:tapDouble]; //右滑手势 UISwipeGestureRecognizer *rightSwip = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(nextPage)]; rightSwip.direction = UISwipeGestureRecognizerDirectionLeft; [scrollView addGestureRecognizer:rightSwip]; //左滑手势 UISwipeGestureRecognizer *leftSwip = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(forwardPage)]; leftSwip.direction = UISwipeGestureRecognizerDirectionRight; [scrollView addGestureRecognizer:leftSwip];}- (void)navBtnOnClick{ [_toolBar showWindow];}//单击屏幕显示隐藏菜单- (void)click{ CGFloat navBarY = _toolBar.frame.origin.y == KMainH - 49 ? -64 : 20; CGFloat toolBarY = _toolBar.frame.origin.y == KMainH - 49 ? KMainH : KMainH - 49; [UIView animateWithDuration:0.25 animations:^{ CGRect temNavBarFrame = self.navigationController.navigationBar.frame; temNavBarFrame.origin.y = navBarY; self.navigationController.navigationBar.frame = temNavBarFrame; CGRect temToolBarFrame = _toolBar.frame; temToolBarFrame.origin.y = toolBarY; _toolBar.frame = temToolBarFrame; }];}//双击屏幕放大缩小图片- (void)doubleClick{ [UIView animateWithDuration:0.25f animations:^{ _scrollView.zoomScale = _scrollView.zoomScale == _minZoomScale ? KPicMaxScale : _minZoomScale; }];}//左滑事件- (void)nextPage{ [_browseView nextPage]; _toolBar.currentPage = _browseView.currentPage;}//右滑事件- (void)forwardPage{ [_browseView prePage]; _toolBar.currentPage = _browseView.currentPage;}#pragma mark - UICouseBrowseToolBarDelegate- (void)browseToolBar:(HWPDFBrowseToolBar *)browseToolBar didClickFinishButtonWithPage:(NSString *)page{ _browseView.currentPage = [page integerValue]; [_browseView reloadView]; [_toolBar dismissKeyboard]; _scrollView.zoomScale = _minZoomScale;}- (void)browseToolBar:(HWPDFBrowseToolBar *)browseToolBar didPageButtonWithAction:(BOOL)nextPage{ if (nextPage) { [self nextPage]; }else { [self forwardPage]; } _scrollView.zoomScale = _minZoomScale;}#pragma mark - UIScrollViewDelegate- (void)scrollViewDidZoom:(UIScrollView *)scrollView{ CGFloat offsetX = (scrollView.bounds.size.width > scrollView.contentSize.width) ? (scrollView.bounds.size.width - scrollView.contentSize.width) * 0.5 : 0.0; CGFloat offsetY = (scrollView.bounds.size.height > scrollView.contentSize.height) ? (scrollView.bounds.size.height - scrollView.contentSize.height) * 0.5 : 0.0; _browseView.center = CGPointMake(scrollView.contentSize.width * 0.5 + offsetX, scrollView.contentSize.height * 0.5 + offsetY - 64);}- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{ return _browseView;}- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ if (scrollView.isZooming) return; //允许翻页的偏移量 CGFloat movePadding = 70.f; //仿苹果原生相册，图片放大后，滑动前在边界时在可以翻页，这里加了±10的偏移量 if (scrollView.contentOffset.x < - movePadding && _lastScrContX < 10) { _scrollView.zoomScale = _minZoomScale; [self forwardPage]; } if (scrollView.contentSize.width - scrollView.contentOffset.x < KMainW - movePadding && scrollView.contentSize.width != 0 && fabsf(_lastScrContX + KMainW - scrollView.contentSize.width) < 10) { _scrollView.zoomScale = _minZoomScale; [self nextPage]; }}//滑动自然停止时调用- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{ _lastScrContX = scrollView.contentOffset.x;}//滑动手动停止时调用- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ _lastScrContX = scrollView.contentOffset.x;}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}@end
PDF文件视图：HWPDFBrowseView
#import @interface HWPDFBrowseView : UIView{ CGPDFDocumentRef pdfDocumentRef;}@property (nonatomic, assign) NSInteger currentPage;@property (nonatomic, assign) NSInteger totalPages;- (id)initWithFilePath:(NSString *)filePath;- (void)reloadView;- (void)prePage;- (void)nextPage;@end/*** ---------------分割线--------------- ***/#import "HWPDFBrowseView.h"@implementation HWPDFBrowseView- (id)initWithFilePath:(NSString *)filePath{ pdfDocumentRef = [self createPDFFromExistFile:filePath]; self = [super initWithFrame:CGPDFPageGetBoxRect(CGPDFDocumentGetPage(pdfDocumentRef, 1), kCGPDFMediaBox)]; return self;}- (CGPDFDocumentRef)createPDFFromExistFile:(NSString *)aFilePath{ CFStringRef path = CFStringCreateWithCString(NULL, [aFilePath UTF8String], kCFStringEncodingUTF8); CFURLRef urlRef = CFURLCreateWithFileSystemPath(NULL, path, kCFURLPOSIXPathStyle, NO); CFRelease(path); CGPDFDocumentRef document = CGPDFDocumentCreateWithURL(urlRef); CFRelease(urlRef); _totalPages = CGPDFDocumentGetNumberOfPages(document); _currentPage = 1; if (_totalPages == 0) return NULL; return document;}- (void)reloadView{ [self setNeedsDisplay];}- (void)drawRect:(CGRect)rect{ CGContextRef context = UIGraphicsGetCurrentContext(); [[UIColor whiteColor] set]; CGContextFillRect(context, rect); CGContextTranslateCTM(context, 0.0, rect.size.height); CGContextScaleCTM(context, 1.0, -1.0); CGPDFPageRef page = CGPDFDocumentGetPage(pdfDocumentRef, _currentPage); CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, rect, 0, true); CGContextConcatCTM(context, pdfTransform); CGContextDrawPDFPage(context, page);}//上一页- (void)prePage{ if(_currentPage < 2) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"提示" message:@"已经第一页了！" delegate:self cancelButtonTitle:@"确定" otherButtonTitles: nil ]; [alert show]; return; } --_currentPage; [self reloadView]; [self transitionWithType:@"pageUnCurl" WithSubtype:kCATransitionFromRight ForView:self];}//下一页- (void)nextPage{ if(_currentPage >= _totalPages) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"提示" message:@"已经最后一页了！" delegate:self cancelButtonTitle:@"确定" otherButtonTitles: nil ]; [alert show]; return; } ++_currentPage; [self reloadView]; [self transitionWithType:@"pageCurl" WithSubtype:kCATransitionFromRight ForView:self];}//设置翻页动画效果- (void)transitionWithType:(NSString *)type WithSubtype:(NSString *)subtype ForView:(UIView *)view{ CATransition *animation = [CATransition animation]; animation.duration = 0.7f; animation.type = type; if (subtype) animation.subtype = subtype; animation.timingFunction = UIViewAnimationOptionCurveEaseInOut; [view.layer addAnimation:animation forKey:@"animation"];}@end
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