问题描述
我已经集成了一个使用AVCaptureSession从相机中捕获照片的库。由于AVCaptureSession仅适用于 4设备，我想禁用此功能旧设备的集成功能。
I have integrated a library that uses AVCaptureSession to capture a photo from the camera. As the AVCaptureSession is only available on iOS 4 devices, I want to disable this integrated functionality for older devices.
我知道应该通过弱链接AVFoundation Framework并检查函数是否存在来完成。弱连接很容易，但我应该检查哪些功能存在？ AVCaptureSession是一个类而不是函数。
I know that it should be done by weak-linking the AVFoundation Framework and checking for function existence. Weak-linking is easy to do, but which function should I check for existence here? AVCaptureSession is a class and not a function.
是否有一些示例代码可用？
Are there some sample code available?
推荐答案
我认为你正在寻找 NSClassFromString ：
Class NSClassFromString ( NSString *aClassName );
然后您可以使用以下内容保护该类的使用：
You can then guard usage of that class with something like this:
if (NSClassFromString(@"AVCaptureSession")) {
...
}
这篇关于iPhone检查是否存在AVCaptureSession类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！