Switching Views from a AlertView Buttons

Question

Application :

It has 3 views Views A,B,C. There is a Alert on View B with 2 buttons on it.

What I do is:

I go from View A to View B. On B, I click on the Alert button to take me back on View A.

Problem:

When i click on the button to again go to View B then it gives an error related to "isValid" property of timer. Timer is declared and used in View B In Other cases, when i use custom button to switch between A & B then it works fine.

The Line where i get Error: BOOL dec = [timer isValid];

What could be Wrong??

Thanks in advance. Your Suggestions are most Welcome

Answer 1

Can you post some code that is responsible for switching views? Also output from log about the error would be usefull for diagnosis.

Answer 2

Hi reecon here is the code information you wanted.

THE CODE FOR ALERT VIEW BUTTON TO SWITCH VIEWS IS

-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {

        if(buttonIndex == 0)
        {
             [self dismissModalViewControllerAnimated:YES];
          }

}

THE CODE WHERE THE PROBLEM OCCURS WHEN SWITCHING BACK TO SAME VIEW IS

-(void)viewWillAppear:(BOOL)animated {

BOOL dec = [timer isValid];

NSLog(@"TIMER CHECK");

    if (dec == YES)
    {
        [timer invalidate];
    }   
}

ERROR THAT IS DISPLAYED IN NSLOG IS :

-[NSCFType isValid]: unrecognized selector sent to instance 0x5996870 2010-10-04 15:49:00.630 sqlite[5263:207] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFType isValid]: unrecognized selector sent to instance 0x5996870' * Call stack at first throw: ( 0 CoreFoundation 0x023e9919 __exceptionPreprocess + 185 1 libobjc.A.dylib 0x025665de objc_exception_throw + 47 2 CoreFoundation 0x023eb42b -[NSObject(NSObject) doesNotRecognizeSelector:] + 187 3 CoreFoundation 0x0235b116 __forwarding + 966 4 CoreFoundation 0x0235acd2 _CF_forwarding_prep_0 + 50 5 sqlite 0x0000393b -[sqliteViewController viewWillAppear:] + 622 6 UIKit 0x0055775d -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:] + 5402 7 UIKit 0x0036e769 -[UIViewController presentModalViewController:withTransition:] + 2937 8 UIKit 0x00367a5e -[UIViewController _tryRecursivelyPresentModalViewController:withTransition:] + 134 9 UIKit 0x0036df42 -[UIViewController presentModalViewController:withTransition:] + 850 10 sqlite 0x00005d8a -[StartPageViewController startQuiz:] + 68 11 UIKit 0x002c2e14 -[UIApplication sendAction:to:from:forEvent:] + 119 12 UIKit 0x0034c6c8 -[UIControl sendAction:to:forEvent:] + 67 13 UIKit 0x0034eb4a -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527 14 UIKit 0x0034d6f7 -[UIControl touchesEnded:withEvent:] + 458 15 UIKit 0x002e62ff -[UIWindow _sendTouchesForEvent:] + 567 16 UIKit 0x002c81ec -[UIApplication sendEvent:] + 447 17 UIKit 0x002ccac4 _UIApplicationHandleEvent + 7495 18 GraphicsServices 0x02c04afa PurpleEventCallback + 1578 19 CoreFoundation 0x023cadc4 CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 52 20 CoreFoundation 0x0232b737 __CFRunLoopDoSource1 + 215 21 CoreFoundation 0x023289c3 __CFRunLoopRun + 979 22 CoreFoundation 0x02328280 CFRunLoopRunSpecific + 208 23 CoreFoundation 0x023281a1 CFRunLoopRunInMode + 97 24 GraphicsServices 0x02c032c8 GSEventRunModal + 217 25 GraphicsServices 0x02c0338d GSEventRun + 115 26 UIKit 0x002d0b58 UIApplicationMain + 1160 27 sqlite 0x00002910 main + 102 28 sqlite 0x000028a1 start + 53 ) terminate called after throwing an instance of 'NSException'

Waiting for your reply. Thanks in advance

Answer 3

Got the reason for it. I was trying to invalidate an already invalidated timer. Thanks Anyways