Question

I’m trying to scroll the pdf file by page

here is my code

-(void)viewDidLoad{

NSString *path = [[NSBundle mainBundle] pathForResource:@"myPdffile" ofType:@"pdf"];

NSURL *url = [NSURL fileURLWithPath:path];

NSURLRequest *urlrequest = [NSURLRequest requestWithURL:url];

[webview loadRequest:urlrequest];

webview.scalesPageToFit = YES;

[super viewDidLoad];

}

//goto next page

-(IBAction)nextpage{

        [webview stringByEvaluatingJavaScriptFromString: ?????? ];
}

//goto previous page

-(IBAction)prevpage {

       ?????
}

what should i put after stringByEvaluatingJavaScriptFromString?

do i put same code in “prevpage”?

thanks!

Answer 1

In iOS 5 you can use this statement for page jumping

[[webView scrollView] setContentOffset:CGPointMake(0,y) animated:YES];

and in below iOS 5 you can use this statement

[webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"window.scrollTo(0.0, %f)", y]];

Where y is the height where you’re going to jump.

Here i am writing some sample code for next and previous page

-(IBAction) nextPage: (id) sender
{
    if (currentPage < numberOfPages) 
    {
        float y =  pageHeight * currentPage++;

        if (isIOSAbove4) 
        {
            [[webView scrollView] setContentOffset:CGPointMake(0,y) animated:YES];
        }
        else
        {
            [webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"window.scrollTo(0.0, %f)", y]];
        }
    }
}

For previous page:

-(IBAction) prevPage: (id) sender
{   
    if (currentPage - 1)
    {
        float y = --currentPage * pageHeight - pageHeight;
        if (isIOSAbove4) 
        {
            [[webView scrollView] setContentOffset:CGPointMake(0,y) animated:YES];
        }
        else
        {
            [webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"window.scrollTo(0.0, %f)", y]];
        }
    }
}

in above sample code isIOSAbove4 is defined in pch file

#define isIOSAbove4 ([[[UIDevice currentDevice] systemVersion] floatValue] >= 5.0)

Hope above code will solve your problem