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

直接回答: 这个问题是因为你已经使用了核心图形元素，如CGContext等，而不是- (void)drawRect:(CGRect)rect这个方法。

现在请将代码移到该方法。它将停止给你警告/错误。

2015-05-14 06:49:28

其他回答

我有这个问题在一个UITextField，当我持有一个空白字段与占位符文本的触摸。我使用以下方法来消除空白字段:

-(void)textFieldDidBeginEditing:(UITextField *)textField{

        textField.text=[@" " stringByAppendingString:textField.text];

        //other stuff here
}


-(BOOL)textFieldShouldReturn:(UITextField *)textField{

         if(textField.text.length>0){
             if([[textField.text substringToIndex:1] isEqualToString:@" "])
                 textField.text=[textField.text substringFromIndex:1];
         }
         //  other stuff here
}

2014-02-17 09:03:52

对我来说，我得到这个错误，因为我正在释放CGContextRef，如下所示:

- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();

    // DRAW BACKGROUND CIRCLE
    CGContextSetFillColorWithColor(context, [[UIColor gray] colorWithAlphaComponent:0.6].CGColor);
    CGContextFillEllipseInRect(context, rect);

//    CGContextRelease(context);
}

删除版本解决了这个问题

2014-08-26 17:41:33

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!

2013-10-25 21:26:38

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()
}

2015-01-16 18:59:43

在某些情况下，你可能需要包含一行#import <QuartzCore/QuartzCore.h>。

2014-07-17 06:46:26

无效上下文0x0在iOS 7.0和系统降级

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