关于这个可怕的问题,我已经阅读了尽可能多的搜索结果,不幸的是,每个搜索结果似乎都集中在一个特定的函数调用上。

我的问题是,我从多个函数得到相同的错误,我猜是从我使用的函数回调的。

更糟糕的是,实际的代码是在另一个项目中导入的自定义私有框架中,因此,调试不是那么简单吗?

有人能告诉我正确的方向吗?我有一种感觉,我正在错误地调用某些方法或与坏的上下文,但xcode的输出在这一点上不是很有帮助。

: CGContextSetFillColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextSetStrokeColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. CGContextSaveGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextSetFlatness: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextAddPath: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextDrawPath: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextRestoreGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextGetBlendMode: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.

当呈现自定义视图或其继承的类之一时,可能会发生这些错误。这时它们会生成多次,直到键盘不再提供任何输入。触摸事件仍然被注册,但是系统变慢,最终可能导致未分配对象错误。

编辑#1:我确实可以访问正在导入的框架,但我没有看到导致问题的类中有任何奇怪的东西。

编辑#2:我刚刚收到一封电子邮件,iOS 7.1已经发布给开发者了。我很好奇这种情况是否会消失,或者变得更糟,或者是否能得到解决。


当前回答

如果在使用UIBezierPath并为描边或填充设置颜色时发生错误,请将设置的颜色代码放在drawRect函数中而不是其他地方。

其他回答

当我在UIActivity子类的activityImage方法中输入错误的图像名称时,我得到了它

- (UIImage *)activityImage
{
    return [UIImage imageNamed:@"img.png"];
}

输入正确的图像为我解决了这个问题。

这些类型的错误是历史上调用核心图形函数的结果,而不是在一个上下文中建立的drawRect或调用之间,如UIGraphicsBeginImageContext和UIGraphicsEndImageContext(或其他UIKit函数,如开始和结束一个上下文)。

话虽如此,但bilobatum说的没错,这一系列错误可能是他在回答中提到的iOS 7漏洞造成的。如果在你的iOS6目标中没有看到这些错误,或者在快速扫描这个私有框架后,你没有发现任何可疑的核心图形调用,这可能只是iOS 7的错误。接得好,双叶巴坦!

我使用下面的代码从上下文创建UIImage:

    UIGraphicsBeginImageContext(size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetFillColorWithColor(context, color.CGColor);
    CGContextFillRect(context, (CGRect){.size = size});

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

这样我就得到了错误。

所以我删除了派生数据内容,重新启动XCode。这招奏效了。

我在自定义CALayer实现的drawInContext(..)方法中得到了这个错误。UIBezierPath尝试使用UIGraphicsGetCurrentContext(),在自定义层中默认为nil。网上的文档解释得很清楚

但是,如果你没有使用UIView对象来绘图,你必须手动使用UIGraphicsPushContext函数将一个有效的上下文推入堆栈。

下面是最终与我的注释内联工作的代码(Swift代码,但解决方案是相同的不管)

override func drawInContext(ctx: CGContext!) {  
    var path = UIBezierPath()

    // 1. Make sure you push the CGContext that was first passed into you.
    UIGraphicsPushContext(ctx)
    path.moveToPoint(CGPoint(x: 0, y: 0))
    path.addLineToPoint(CGPoint(x: 150, y: 150))
    var lineColor = UIColor.blueColor()
    lineColor.setStroke()
    path.lineWidth = 2
    path.stroke(
    // 2. Pop the context after you are done.
    UIGraphicsPopContext()
}

对我来说,答案是我不必要地释放了drawRect:中的图形上下文。在CGPostError上抛出一个符号断点使我找到了罪魁祸首。