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。

 

pdfViewController.h

 

#import <UIKit/UIKit.h>
#import "PDFView.h"

@interface pdfViewController : UIViewController {
	IBOutlet PDFView *pdfview;
}

- (IBAction)goNextPage:(id)sender;
- (IBAction)goPrePage:(id)sender;
@end

 

pdfViewController.m

 

#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

 

#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

 

PDFView.m

 

#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