iOS開發筆記——PDF的顯示和瀏覽

       今天的任務是：在iOS上加載顯示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.實現簡單

        2.還是實現簡單

弊：1.僅能瀏覽，拿不到任何回調，safari不會鳥任何人。

        2.固定豎版拖動，想實現翻頁動效果就扒瞎

        

        下面的方法可以解決webview 顯示pdf的弊，相對的，要付出一些汗水作爲代價了。

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);
}

這樣顯示出來的pdf單頁是倒立的，Quartz座標系和UIView座標系不一樣所致，調整座標系，使pdf正立：

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

配合iOS5強大的UIPageViewController實現翻頁瀏覽

- (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];
}

後續將完成塗鴉pdf後保存創建新pdf的功能。

特別感謝cclv的幫助和指點。