无效上下文0x0在iOS 7.0和系统降级

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

其他人会要求你在访问核心图形上下文的地方发布代码，但我怀疑这是问题所在。这些无效的上下文0x0错误消息很常见，很容易在iOS 7中重现。事实上，我可以使用零代码的故事板重现错误。我在IB中拖动UITextField到画布上，运行应用程序，双击文本字段内。

在许多情况下，我很难认真对待无效上下文0x0错误消息。我不知道您的情况是否值得更大的关注(我同意Rob Napier的观点，这是值得研究的，特别是如果您显式地使用图形上下文)。

在我自己的项目中，我希望有一天这些错误会神奇地消失(但这一天并没有伴随着7.0.3)。

更新:在安装Xcode 5.1并瞄准iOS 7.1后，我再也不能通过双击空文本字段来重现错误。

2013-10-25 21:26:16

其他回答

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

确定尺寸。宽度或大小。高度不为0，

你可以在CGPostError中添加符号断点来检查

2014-03-11 07:46:21

I have had cases where the context returned from UIGraphicsGetCurrentContext() is NULL, and if you try using it for anything this message appears. It is the view's responsibility to push a context using UIGraphicsPushContext prior to calling drawRect:, if you call drawRect: directly instead of [view setNeedsDisplay] you risk the context not being set yet. My hunch is that prior to iOS 7 the context was pushed for the view on init, and now on iOS 7 the context isn't pushed until the first time drawRect: is about to be called. I suspect some UIKit code is calling drawRect: directly and this is why there are issues with some code even when no custom drawing is being done.

解决方案(如果做自定义绘图):

不要直接调用drawRect:，使用[view setNeedsDisplay]，或者如果你需要立即绘图，使用[view。层画) 在你的drawRect:获取上下文，但不要在if语句体之外使用if (context) {<do drawing here>}

2014-01-14 17:54:33

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。

2014-04-03 22:10:10

我也有同样的问题。在我的项目中，我尝试创建一个文本字段，并将其添加到我的pdf文件。旧的代码:

- (void) drawInContext:(CGContextRef)context {
    //Otherwise we're upside-down
    CGContextSetTextMatrix(context, CGAffineTransformMake(1.0,0.0, 0.0, -1.0, 0.0, 0.0));

    CGContextSetTextDrawingMode(context, kCGTextFill); // This is the default
    [[UIColor blackColor] setFill]; // ***This is the problem ***

    CGFloat x = self.rect.origin.x;
    CGFloat y = self.rect.origin.y + self.font.pointSize;
    [self.text drawAtPoint:CGPointMake(x, y)
            withAttributes:@{NSFontAttributeName:[UIFont fontWithName:@"Arial" size:12]}];
}

解决此问题后，代码更改为:

old:[[UIColor blackColor] setFill]; 

new:CGContextSetFillColorWithColor(context, [[UIColor blackColor] CGColor]);

我发现解决方案在UIColor SetFill不工作。谢谢那个帮手。

2014-12-03 07:41:18

从模拟器卸载应用程序，并再次运行

2014-09-12 09:43:30

无效上下文0x0在iOS 7.0和系统降级

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