为什么我在安装 iPhone 应用程序时收到 CGContext 错误？

Question

为什么我在尝试安装 iPhone 应用程序时收到以下错误？

warning: Unable to read symbols for /Library/MobileSubstrate/MobileSubstrate.dylib (file not found).
warning: Unable to read symbols for /Library/Frameworks/CydiaSubstrate.framework/Libraries/SubstrateLoader.dylib (file not found).
2011-02-18 21:57:05.038 Catalog Dev[399:307] MS:Notice: Installing: com.yourcompany.Catalog-Dev [Catalog Dev] (550.32)
2011-02-18 21:57:05.210 Catalog Dev[399:307] MS:Notice: Loading: /Library/MobileSubstrate/DynamicLibraries/Activator.dylib
warning: Unable to read symbols for /Library/MobileSubstrate/DynamicLibraries/Activator.dylib (file not found).
2011-02-18 21:57:05.518 Catalog Dev[399:307] MS:Notice: Loading: /Library/MobileSubstrate/DynamicLibraries/sandcastleclient.dylib
warning: Unable to read symbols for /Library/MobileSubstrate/DynamicLibraries/sandcastleclient.dylib (file not found).
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.0.2/Symbols/usr/lib/libsubstrate.dylib (file not found).
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextDrawImage: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextSetStrokeColorWithColor: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextSetLineWidth: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextMoveToPoint: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextAddLineToPoint: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextAddLineToPoint: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextAddLineToPoint: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextAddLineToPoint: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGContextDrawPath: invalid context 0x0
Fri Feb 18 21:57:11 Moes-iPhone Catalog Dev[399] <Error>: CGBitmapContextCreateImage: invalid context 0x0

Answer 1

看来您正在尝试安装她的部署目标大于您的 iPhone 操作系统版本的应用程序。 Xcode 抱怨他弄乱了你的代码试图使用的一些 lybreris。

Answer 2

如果您创建了一个使用第三方框架（例如 CydiaSubstrate.framework）的应用，则必须将该框架复制到应用程序包内的 Frameworks 文件夹中。

可以在此处找到有关在 Xcode 中自动执行此过程的优秀教程。

更新：

<Error>: CGContextDrawImage: invalid context 0x0 

此错误表明您已调用 CGContextDrawImage 但未指定有效的 CGContextRef 参数。如果没有看到相关代码，我就不得不猜测发生了什么。 CGContextDrawImage 的原型如下：

void CGContextDrawImage (
    CGContextRef c,
    CGRect rect,
    CGImageRef image
);

第一个参数必须是有效的 图形上下文，通常是当前绘图上下文，访问方式如下：

CGContextRef myContext = [[NSGraphicsContext currentContext] graphicsPort];
...
CGContextDrawImage(myContext, someRect, someImage);