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I have a custom UIButton class that adds a gradient and a gloss effect to the UIButton the code works perfectly in iOS 4 and on iOS5 simulator but when i run it on iOS 5 devices it gives me the exception EXC_BAD_ACCESS , the exception is triggered by the line :
CGContextStrokePath(context);
any help is really appreciated , here's 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 wanna now is that is it really related to iOS 5 or am i doing something else wrong ?
The crash happens because the UIColors are already deallocated when you access the CGColorRefs.
An easy way to avoid this is to use
UIColor* blackColor = [UIColor blackColor];
CGContextSetStrokeColorWithColor(context, [blackColor CGColor]);
instead of
CGColorRef* blackColor = [[UIColor blackColor] CGColor];
CGContextSetStrokeColorWithColor(context, blackColor);
so ARC doesn't get the chance to deallocate the UIColor objects early.
来源:https://stackoverflow.com/questions/11229362/cgcontextstrokepath-triggers-exc-bad-access-in-ios-5