CGContextStrokePath launches EXC_BAD_ACCESS on iOS> 5

Question

I have a custom UIButton class that adds a gradient and glitter effect to UIButton, the code works fine in iOS 4 and on the iOS5 simulator, but when I run it on iOS 5 devices, it gives me an EXC_BAD_ACCESS exception, the exception is triggered by the line:

CGContextStrokePath(context); 

any help really appreciated here is my code

 - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGFloat actualBrightness = _brightness; if (self.selected) { actualBrightness -= 0.10; } CGColorRef blackColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0].CGColor; CGColorRef highlightStart = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.7].CGColor; CGColorRef highlightStop = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0].CGColor; CGColorRef outerTop = [UIColor colorWithHue:_hue saturation:_saturation brightness:1.0*actualBrightness alpha:1.0].CGColor; CGColorRef outerBottom = [UIColor colorWithHue:_hue saturation:_saturation brightness:0.80*actualBrightness alpha:1.0].CGColor; CGFloat outerMargin = 7.5f; CGRect outerRect = CGRectInset(self.bounds, outerMargin, outerMargin); CGMutablePathRef outerPath = createRoundedRectForRect(outerRect, 6.0); // Draw gradient for outer path CGContextSaveGState(context); CGContextAddPath(context, outerPath); CGContextClip(context); drawLinearGradient(context, outerRect, outerTop, outerBottom); CGContextRestoreGState(context); if (!self.selected) { CGRect highlightRect = CGRectInset(outerRect, 1.0f, 1.0f); CGMutablePathRef highlightPath = createRoundedRectForRect(highlightRect, 6.0); CGContextSaveGState(context); CGContextAddPath(context, outerPath); CGContextAddPath(context, highlightPath); CGContextEOClip(context); drawLinearGradient(context, CGRectMake(outerRect.origin.x, outerRect.origin.y, outerRect.size.width, outerRect.size.height/3), highlightStart, highlightStop); CGContextRestoreGState(context); drawCurvedGloss(context, outerRect, 180); CFRelease(highlightPath); } else { //reverse non-curved gradient when pressed CGContextSaveGState(context); CGContextAddPath(context, outerPath); CGContextClip(context); drawLinearGloss(context, outerRect, TRUE); CGContextRestoreGState(context); } if (!_toggled) { //bottom highlight CGRect highlightRect2 = CGRectInset(self.bounds, 6.5f, 6.5f); CGMutablePathRef highlightPath2 = createRoundedRectForRect(highlightRect2, 6.0); CGContextSaveGState(context); CGContextSetLineWidth(context, 0.5); CGContextAddPath(context, highlightPath2); CGContextAddPath(context, outerPath); CGContextEOClip(context); drawLinearGradient(context, CGRectMake(self.bounds.origin.x, self.bounds.size.height-self.bounds.size.height/3, self.bounds.size.width, self.bounds.size.height/3), highlightStop, highlightStart); CGContextRestoreGState(context); CFRelease(highlightPath2); } else { //toggle marker CGRect toggleRect= CGRectInset(self.bounds, 5.0f, 5.0f); CGMutablePathRef togglePath= createRoundedRectForRect(toggleRect, 8.0); CGContextSaveGState(context); CGContextSetLineWidth(context, 3.5); CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor); CGContextAddPath(context, togglePath); CGContextStrokePath(context); CGContextRestoreGState(context); CFRelease(togglePath); } // Stroke outer path CGContextSaveGState(context); CGContextSetLineWidth(context, 0.5); CGContextSetStrokeColorWithColor(context, blackColor); CGContextAddPath(context, outerPath); CGContextStrokePath(context); CGContextRestoreGState(context); CFRelease(outerPath); } 

what i really want now is it really connected with iOS 5, or am i doing something else wrong?

Answer 1

The crash occurs because UIColors are already freed when accessing CGColorRefs.

An easy way to avoid this is to use

 UIColor* blackColor = [UIColor blackColor]; CGContextSetStrokeColorWithColor(context, [blackColor CGColor]); 

instead

 CGColorRef* blackColor = [[UIColor blackColor] CGColor]; CGContextSetStrokeColorWithColor(context, blackColor); 

therefore, ARC will not be able to release UIColor objects early.