iOS开发笔记——PDF的显示和浏览

       今天的任务是：在iOS上加载显示pdf文件。

方法一：利用webview

-(void)loadDocument:(NSString *)documentName inView:(UIWebView *)webView
{
    NSString *path = [[NSBundle mainBundle] pathForResource:documentName ofType:nil];
    NSURL *url = [NSURL fileURLWithPath:path];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [webView loadRequest:request];
}

利：1.实现简单

        2.还是实现简单

弊：1.仅能浏览，拿不到任何回调，safari不会鸟任何人。

        2.固定竖版拖动，想实现翻页动效果就扒瞎

        

        下面的方法可以解决webview 显示pdf的弊，相对的，要付出一些汗水作为代价了。

方法二：利用CGContextDrawPDFPage

CGPDFDocumentRef GetPDFDocumentRef(NSString *filename)
{
    CFStringRef path;
    CFURLRef url;
    CGPDFDocumentRef document;
    size_t count;
    
    path = CFStringCreateWithCString (NULL, [filename UTF8String], kCFStringEncodingUTF8);
    url = CFURLCreateWithFileSystemPath (NULL, path, kCFURLPOSIXPathStyle, 0);
    
    CFRelease (path);
    document = CGPDFDocumentCreateWithURL (url);
    CFRelease(url);
    count = CGPDFDocumentGetNumberOfPages (document);
    if (count == 0) {
        printf("[%s] needs at least one page!\n", [filename UTF8String]);
        return NULL; 
    } else {
        printf("[%ld] pages loaded in this PDF!\n", count);
    }
    return document;
}

void DisplayPDFPage (CGContextRef myContext, size_t pageNumber, NSString *filename)
{
    CGPDFDocumentRef document;
    CGPDFPageRef page;
    
    document = GetPDFDocumentRef (filename);
    page = CGPDFDocumentGetPage (document, pageNumber);
    CGContextDrawPDFPage (myContext, page);
    CGPDFDocumentRelease (document);
}

这样显示出来的pdf单页是倒立的，Quartz坐标系和UIView坐标系不一样所致，调整坐标系，使pdf正立：

    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(context, 80, self.frame.size.height-60);
    CGContextScaleCTM(context, 1, -1);

配合iOS5强大的UIPageViewController实现翻页浏览

- (PDFViewController *)viewControllerAtIndex:(NSUInteger)index 
{
    //Return the PDFViewController for the given index.
    if (([self.pagePDF count] == 0 )|| (index > [self.pagePDF count]) ) {
        return nil;
    }
    
    //Create a new view controller and pass suitable data.
    PDFViewController *dataViewController = [[PDFViewController alloc]initWithNibName:@"PDFViewController" bundle:nil];
    //dataViewController.pdfview = [self.pagePDF objectAtIndex:index];
    dataViewController.pdfview = [[PDFView alloc]initWithFrame:self.view.frame atPage:index];
    [dataViewController.view addSubview:dataViewController.pdfview];
    NSLog(@"index = %d",index);
    return dataViewController;
}

- (NSUInteger) indexOfViewController:(PDFViewController *)viewController
{
    return [self.pagePDF indexOfObject:viewController.pdfview];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
    NSUInteger index = [self indexOfViewController:(PDFViewController *)viewController];
    if ((index == 0 ) || (index == NSNotFound)){
        return nil;
    }
    
    index--;
    return  [self viewControllerAtIndex:index];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger index = [self indexOfViewController:(PDFViewController *)viewController];
    if (index == NSNotFound)
    {
        return nil;
    }
    
    index++;
    
    if (index == [self.pagePDF count]){
        return  nil;
    }
    
    return [self viewControllerAtIndex:index];
}

后续将完成涂鸦pdf后保存创建新pdf的功能。

特别感谢cclv的帮助和指点。