CODEWITHSUNDEEP
iphoneiosobjective-cios5
Raju
Raju

Reputation: 451

Application crashing after 10 second or executing "renderInContext" 12 or more times

I am using the following code to convert HTML to PDF.

UIGraphicsBeginPDFContextToFile(self.filePath, CGRectZero, nil);    //creating PDF

    int i = 0;
    for (; i < pages; i++)
    {
        if (pageHeight * (i+1) > height)
        {
            CGRect f = [myWebPage frame];
            f.size.height -= (((i+1) * pageHeight) - height);
            [myWebPage setFrame: f];
        }
        // Specify the size of the pdf page
        UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, width, pageHeight), nil);
        CGContextRef currentContext =  UIGraphicsGetCurrentContext();
        [[[myWebPage subviews] lastObject] setContentOffset:CGPointMake(0, pageHeight * i) animated:NO];
        [myWebPage.layer renderInContext: currentContext];
        NSLog(@"I = %d",i);
    }

UIGraphicsEndPDFContext();
[[[myWebPage subviews] lastObject] setContentOffset:CGPointMake(0, 0) animated:NO];
[myWebPage setFrame:origframe];

but the loop is getting crashed after 10 second or for i >= 12,

its getting crashed at : 

 [myWebPage.layer renderInContext: currentContext];

i have tried with "CGContextRelease(currentContext);" also but its not working..

May I please know why is it crashing and how to prevent crashing of app.

Console output:

2013-06-06 10:15:26.179 app[8084:907] Width : 980.000000
2013-06-06 10:15:26.180 app[8084:907] NUMBER OF PAGES : 15
2013-06-06 10:15:26.382 app[8084:907] I = 0
2013-06-06 10:15:28.400 app[8084:907] I = 1
2013-06-06 10:15:28.903 app[8084:907] I = 2
2013-06-06 10:15:30.330 app[8084:907] I = 3
2013-06-06 10:15:31.524 app[8084:907] I = 4
2013-06-06 10:15:32.641 app[8084:907] I = 5
2013-06-06 10:15:33.470 app[8084:907] I = 6
2013-06-06 10:15:34.634 app[8084:907] I = 7
2013-06-06 10:15:35.791 app[8084:907] I = 8
2013-06-06 10:15:36.970 app[8084:907] I = 9
2013-06-06 10:15:38.108 app[8084:907] I = 10
2013-06-06 10:15:38.927 app[8084:907] I = 11

and app getting crashed in iPhone (Working properly in simulator )

(UPDATED) : and in other case its showing : 

2013-06-06 11:17:33.023 app[8202:907] Width : 320.000000
2013-06-06 11:17:33.024 app[8202:907] NUMBER OF PAGES : 2
2013-06-06 11:17:38.200 app[8202:907] I = 0
2013-06-06 11:17:41.390 app[8202:907] I = 1
2013-06-06 11:17:44.028 app[8202:2103] void SendDelegateMessage(NSInvocation *): delegate (webView:didFinishLoadForFrame:) failed to return after waiting 10 seconds. main    run loop mode: kCFRunLoopDefaultMode
(lldb)

and 

 libsystem_kernel.dylib`mach_msg_trap:
 0x3aa45e1c:  mov    r12, sp
 0x3aa45e20:  push   {r4, r5, r6, r8}
 0x3aa45e24:  ldm    r12, {r4, r5, r6}
 0x3aa45e28:  mvn    r12, #30
 0x3aa45e2c:  svc    #128
 0x3aa45e30:  pop    {r4, r5, r6, r8}  <=== Thread 1: singal SIGSTOP
 0x3aa45e34:  bx     lr

Please help me out..

Upvotes: 0

Views: 1366

Answers (2)

Warren Burton
Warren Burton

Reputation: 17378

A WebView has a delegate protocol frameLoadDelegate which conforms to WebFrameLoadDelegate

One of the methods that you may implement is

- (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame

Your crash is showing

2013-06-06 11:17:44.028 app[8202:2103] void SendDelegateMessage(NSInvocation *): delegate (webView:didFinishLoadForFrame:) failed to return after waiting 10 seconds. main run loop mode: kCFRunLoopDefaultMode

Which indicates perhaps theres an issue with the default implementation

You may wish to set your frameLoadDelegate on myWebPage to SomeArbitraryObject (maybe the object which owns myWebPage ) and implement that method as empty 

- (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame
{
//nothing to see here, move along
}

Upvotes: 0

Walt Sellers
Walt Sellers

Reputation: 3939

Your loop is blocking the main thread for too long. The iOS watchdog process will kill your app with exception 0x8badfood when the main thread does not respond to the watchdog for 10 seconds.

You need to break the work up into pieces so the main thread gets time to talk to the iOS every 8 or 9 seconds. Or move work to other threads.

Upvotes: 1

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