Question

我写了这个UIImage的简单扩展，从预定义的颜色和大小开始绘制图像。

这是代码：

extension UIImage {

    class func image(color:UIColor, size:CGSize)->UIImage {

        UIGraphicsBeginImageContextWithOptions(size, true, 2.0);

        let context = UIGraphicsGetCurrentContext()
        let rect = CGRectMake(0, 0, size.width, size.height)

        color.set()

        CGContextFillRect(context, rect)
        var image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image
    }
}

如果我在控制器的ViewDidLoad方法中启动此代码，我会收到此错误

Oct 31 16:48:02 iPhone Budjet_v2[3387] <Error>: 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.
Oct 31 16:48:02 iPhone Budjet_v2[3387] <Error>: 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.
Oct 31 16:48:02 iPhone Budjet_v2[3387] <Error>: CGContextFillRects: 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.
fatal error: unexpectedly found nil while unwrapping an Optional value

我无法理解我的代码有什么问题。

Answer 1

这似乎是iOS 7中引入的错误。答案here中列出了创建此错误的完整方法列表。

此问题的建议行动方案是向CGPostError添加一个符号断点，以便在发生此错误时分析堆栈，以确定触发此错误的内容。

此错误可能由多种情况触发，如果没有进一步研究，无法确定哪种情况会触发错误。

祝你好运！

Answer 2

    if (!(CGSizeEqualToSize(size, CGSizeZero))){

    // your drawing code....

    }else{


return nil;

}

（这个ObjC很明显，道歉，我还不是一个有成就的快速甩手...... 我怀疑你的问题是大小的上下文（0,0）

以编程方式创建UIImage - 代码错误

2 个答案: