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

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

其他回答

我得到了代码错误

UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:pointA];
[path addLineToPoint:pointB];
[path addLineToPoint:pointC];
[[UIColor colorWithHexString:@"EFEFEF"] set];
[path fill];
[path closePath];

CAShapeLayer *triangle = [CAShapeLayer layer];
triangle.fillColor = [UIColor colorWithHexString:@"EFEFEF"].CGColor;
triangle.path = path.CGPath;

return triangle;

并在删除代码后

[[UIColor colorWithHexString:@"EFEFEF"] set];
[path fill];

世界变得寂静

2016-03-23 08:27:13

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

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

这有点俗气，但对我很管用。

我在UITableViewCell的init中设置了UIImageView，给它一个大小和约束。

然后在我的视图控制器的cellForRowAtIndexPath中我这样做:

let img = PFImageView(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
img.setImage(withFile: nil, defaultText: message.senderUsername)
cell.profileImageView?.image = img.image

这避免了错误，在函数下面，我为UIImageView设置了实际图像。上面的代码是一个很好的默认值

2018-09-05 15:17:33

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

无效上下文0x0在iOS 7.0和系统降级

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