A.m
- (CAShapeLayer *)createIndicatorWithColor:(UIColor *)color andPosition:(CGPoint)point {
CAShapeLayer *layer = [CAShapeLayer new];
UIBezierPath *bezierPath = [UIBezierPath bezierPath];
[bezierPath moveToPoint:CGPointMake(0, 0)];
[bezierPath addLineToPoint:CGPointMake(4, 5)];
[bezierPath addLineToPoint:CGPointMake(8, 0)];
[bezierPath stroke];//ios12 崩溃
layer.strokeColor = [kSelectedColor CGColor];
//设置填充颜色 如果只要边 可以把里面设置成[UIColor ClearColor]
layer.fillColor = [[UIColor clearColor]CGColor];
layer.path = bezierPath.CGPath;
layer.lineWidth = 1.0;
CGPathRef bound = CGPathCreateCopyByStrokingPath(layer.path, nil, layer.lineWidth, kCGLineCapButt, kCGLineJoinMiter, layer.miterLimit);
layer.bounds = CGPathGetBoundingBox(bound);
CGPathRelease(bound);
layer.position = point;
return layer;
}
B.m
/*
*开始绘制
*/
-(void) drawTextInRect:(CGRect)requestedRect
{
[self initAttributedString];
//排版
if (attributedString==nil) {
return;
}
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);
CGMutablePathRef leftColumnPath = CGPathCreateMutable();
CGPathAddRect(leftColumnPath, NULL ,CGRectMake(0 , 0 ,self.bounds.size.width , self.bounds.size.height));
CTFrameRef leftFrame = CTFramesetterCreateFrame(framesetter,CFRangeMake(0, 0), leftColumnPath , NULL);
//翻转坐标系统（文本原来是倒的要翻转下）
CGContextRef context = UIGraphicsGetCurrentContext();
UIGraphicsPushContext(context);//别忘了调UIGraphicsPopContext();
CGContextSetTextMatrix(context , CGAffineTransformIdentity);
CGContextTranslateCTM(context , 0 ,self.bounds.size.height);
CGContextScaleCTM(context, 1.0 ,-1.0);
//画出文本
CTFrameDraw(leftFrame,context);
//释放
CGPathRelease(leftColumnPath);
CFRelease(framesetter);
// UIGraphicsPushContext(context);
// push：UIGraphicsPushContext(context)把context压入栈中，并把context设置为当前绘图上下文
// pop：UIGraphicsPopContext将栈顶的上下文弹出，恢复先前的上下文，但是绘图状态不变
// 不实现UIGraphicsPopContext();会和 [bezierPath stroke];冲突程序crash
UIGraphicsPopContext();
}
B.m类中别人写的代码只调用了UIGraphicsPushContext(context);，忘记调用UIGraphicsPopContext();。
结果造成了奇葩问题：
当执行B后再执行A，在iOS12中，A.m中调用[bezierPath stroke];时程序crash。
What the fuck！
