Question

I am showing a custom alert view which is derived from UIAlertView in my view controller, and when I rotate the device for like 2-3 times, both the view controller and the alert view gets rotated. But then the app crashes with no clear clues. I have a breakpoint on All Exceptions but it can’t catch it.

This crash is not happening if I use a standard UIAlertView. I found the custom alertview’s code from someone else. Is there something misimplemented here? Or how can I get more clues of what’s happening?

@implementation CustomAlertView


- (void) setBackgroundColor:(UIColor *) background 
            withStrokeColor:(UIColor *) stroke
{
    if(fillColor != nil)
    {
        [fillColor release];
        [borderColor release];
    }

    fillColor = [background retain];
    borderColor = [stroke retain];
}

- (id)initWithFrame:(CGRect)frame
{
    if((self = [super initWithFrame:frame]))
    {
        if(fillColor == nil)
        {

        }
    }

    return self;
}

- (void)layoutSubviews
{
    for (UIView *sub in [self subviews])
    {
        if([sub class] == [UIImageView class] && sub.tag == 0)
        {
            // The alert background UIImageView tag is 0, 
            // if you are adding your own UIImageView's 
            // make sure your tags != 0 or this fix 
            // will remove your UIImageView's as well!
            [sub removeFromSuperview];
            break;
        }
    }
}

- (void)drawRect:(CGRect)rect
{   
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextClearRect(context, rect);
    CGContextSetAllowsAntialiasing(context, true);
    CGContextSetLineWidth(context, 0.0);
    CGContextSetAlpha(context, 0.8); 
    CGContextSetLineWidth(context, 2.0);
    CGContextSetStrokeColorWithColor(context, [borderColor CGColor]);
    CGContextSetFillColorWithColor(context, [fillColor CGColor]);

    // Draw background
    CGFloat backOffset = 2;
    CGRect backRect = CGRectMake(rect.origin.x + backOffset, 
                                 rect.origin.y + backOffset, 
                                 rect.size.width - backOffset*2, 
                                 rect.size.height - backOffset*2);

    [self drawRoundedRect:backRect inContext:context withRadius:8];
    CGContextDrawPath(context, kCGPathFillStroke);

    // Clip Context
    CGRect clipRect = CGRectMake(backRect.origin.x + backOffset-1, 
                                 backRect.origin.y + backOffset-1, 
                                 backRect.size.width - (backOffset-1)*2, 
                                 backRect.size.height - (backOffset-1)*2);

    [self drawRoundedRect:clipRect inContext:context withRadius:8];
    CGContextClip (context);

    //Draw highlight
    CGGradientRef glossGradient;
    CGColorSpaceRef rgbColorspace;
    size_t num_locations = 2;
    CGFloat locations[2] = { 0.0, 1.0 };
    CGFloat components[8] = { 1.0, 1.0, 1.0, 0.35, 1.0, 1.0, 1.0, 0.06 };
    rgbColorspace = CGColorSpaceCreateDeviceRGB();
    glossGradient = CGGradientCreateWithColorComponents(rgbColorspace, 
                                                        components, locations, num_locations);

    CGRect ovalRect = CGRectMake(-130, -115, (rect.size.width*2), 
                                 rect.size.width/2);

    CGPoint start = CGPointMake(rect.origin.x, rect.origin.y);
    CGPoint end = CGPointMake(rect.origin.x, rect.size.height/5);

    CGContextSetAlpha(context, 1.0); 
    CGContextAddEllipseInRect(context, ovalRect);
    CGContextClip (context);

    CGContextDrawLinearGradient(context, glossGradient, start, end, 0);

    CGGradientRelease(glossGradient);
    CGColorSpaceRelease(rgbColorspace); 
}

- (void) drawRoundedRect:(CGRect) rrect inContext:(CGContextRef) context 
              withRadius:(CGFloat) radius
{
    CGContextBeginPath (context);

    CGFloat minx = CGRectGetMinX(rrect), midx = CGRectGetMidX(rrect), 
    maxx = CGRectGetMaxX(rrect);

    CGFloat miny = CGRectGetMinY(rrect), midy = CGRectGetMidY(rrect), 
    maxy = CGRectGetMaxY(rrect);

    CGContextMoveToPoint(context, minx, midy);
    CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
    CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
    CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
    CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
    CGContextClosePath(context);
}

- (void)disableDismissForIndex:(int)index_{

    canIndex = index_;
    disableDismiss = TRUE;
}

- (void)dismissAlert{

    [self dismissWithClickedButtonIndex:[self cancelButtonIndex] animated:YES];

}

- (void)vibrateAlert:(float)seconds{
    canVirate = TRUE;

    [self moveLeft];

    [self performSelector:@selector (stopVibration) withObject:nil afterDelay:seconds];
}

-(void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated {

    if (disableDismiss == TRUE && canIndex == buttonIndex){

    }else {


    [super dismissWithClickedButtonIndex:buttonIndex animated:animated];

    }
}


- (void)hideAfter:(float)seconds{

    [self performSelector:@selector (dismissAlert) withObject:nil afterDelay:seconds];

}

- (void)moveRight{

    if (canVirate){

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:0.05];

        self.transform = CGAffineTransformMakeTranslation(-10.0, 0.0);

        [UIView commitAnimations];

        [self performSelector:@selector (moveLeft) withObject:nil afterDelay:0.05];

    }

}
- (void)moveLeft{

    if (canVirate){

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.05];

    self.transform = CGAffineTransformMakeTranslation(10.0, 0.0);

    [UIView commitAnimations];

  [self performSelector:@selector (moveRight) withObject:nil afterDelay:0.05];

    }
}

- (void)stopVibration{

    canVirate = FALSE;

    self.transform = CGAffineTransformMakeTranslation(0.0, 0.0);
}

@end

Answer 1

OK now I found it. In layoutViews method, replacing [sub removeFromSuperview]; line with ((UIImageView*)sub).image = nil; fixed the problem for me. Still I’m not sure about the exact reason though.