读取PDF（二）
以前写了一篇文章：读取PDF，这篇文章实现了同样的功能，在原来的基础上增加了上一页和下一页的功能。
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pdfViewController.h
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#import <UIKit/UIKit.h>#import "PDFView.h"@interface pdfViewController : UIViewController {IBOutlet PDFView *pdfview;}- (IBAction)goNextPage:(id)sender;- (IBAction)goPrePage:(id)sender;@end?pdfViewController.m
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#import "pdfViewController.h"@implementation pdfViewController- (void)viewDidLoad {pdfview = [[PDFView alloc] initWithFrame:pdfview.frame andFileName:@"metro.pdf"]; [self.view addSubview:pdfview]; [pdfview release]; [super viewDidLoad];}- (IBAction)goNextPage:(id)sender{ [pdfview goDownPage];}- (IBAction)goPrePage:(id)sender{ [pdfview goUpPage];}@end?
PDFView.h
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#import <UIKit/UIKit.h>@interface PDFView : UIView {//这个类封装了PDF画图的所有信息CGPDFDocumentRef pdf;//PDFDocument中的一页CGPDFPageRef page;//总共页数int totalPages;//当前的页面int currentPage;}//当前视图初始化类，在该方法中会创建一个CGPDFDocuemntRef对象，传递一个PDF文件的名字和所需要页面的大小- (id)initWithFrame:(CGRect)frame andFileName:(NSString *)fileName;//创建一个PDF对象，此方法在初始化方法中被调用- (CGPDFDocumentRef)createPDFFromExistFile:(NSString *)aFilePath;- (void)reloadView;//页面之间的跳转- (void)goUpPage; - (void)goDownPage;@end?
#import "PDFView.h"@implementation PDFView- (id)initWithFrame:(CGRect)frame andFileName:(NSString *)fileName {if (self = [super initWithFrame:frame]) {NSString *dataPathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:fileName];pdf = [self createPDFFromExistFile:dataPathFromApp];self.backgroundColor = [UIColor clearColor];}return self;}- (CGPDFDocumentRef)createPDFFromExistFile:(NSString *)aFilePath {CFStringRef path;CFURLRef url;CGPDFDocumentRef document;path = CFStringCreateWithCString(NULL, [aFilePath UTF8String], kCFStringEncodingUTF8);url = CFURLCreateWithFileSystemPath(NULL, path, kCFURLPOSIXPathStyle, NO);CFRelease(path);document = CGPDFDocumentCreateWithURL(url);CFRelease(url);totalPages = CGPDFDocumentGetNumberOfPages(document);currentPage = 1; if (totalPages == 0) {return NULL;}return document;}- (void)drawRect:(CGRect)rect {//得到绘图上下文环境 CGContextRef context = UIGraphicsGetCurrentContext();//得到一个PDF页面 page = CGPDFDocumentGetPage(pdf, currentPage);//进行坐标转换，这是因为Quartz的坐标系统是以左下角为起始点，但iPhone视图是以左上角为起始点 CGContextTranslateCTM(context, 0.0,self.bounds.size.height); //转变坐标系 CGContextScaleCTM(context, 1.0, -1); CGContextDrawPDFPage(context, page);}- (void)dealloc { [super dealloc];}- (void)reloadView {[self setNeedsDisplay];}- (void)goUpPage {if(currentPage < 2)return;--currentPage;[self reloadView];}- (void)goDownPage {if(currentPage >= totalPages)return;++currentPage;[self reloadView];}@end