ios - 如何使用静态函数通过完成处理程序调用 UIImageWriteToSavedPhotosAlbum()？

Question

我可以调用 UIImageWriteToSavedPhotosAlbum 并毫无问题地处理完成:

class A {
    func saveNow() {
        UIImageWriteToSavedPhotosAlbum(someImage, self, "saveImage:didFinishSavingWithError:contextInfo:", nil)
    }

    func saveImage(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafePointer<Void>) {
        // handle completion
    }
}

但是，如果我想让 saveNow() 成为静态函数，我就无法正确设置 completionTarget 和 completionSelector我可以处理完成:

class B {
    static func saveNow() {
        UIImageWriteToSavedPhotosAlbum(someImage, /* how to set here */)
    }

    static func saveImage completionSelector(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafePointer<Void>) {
    }
}

如果要使用静态函数，如何修改类B？

Answer 1

您需要做的是将目标设置为 YourClassName.self。

即，

UIImageWriteToSavedPhotosAlbum(someImage, YourClassName.self, "saveImage:didFinishSavingWithError:contextInfo:", nil)

顺便说一句，你的函数名不正确:

//Note the space between saveImage and completionSelector
static func saveImage completionSelector(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafePointer<Void>) 

我认为应该是:

static func saveImageWithCompletionSelector(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafePointer<Void>) 

因此，我们可能需要做相应的改变:

UIImageWriteToSavedPhotosAlbum(someImage, YourClassName.self, "saveImageWithCompletionSelector:didFinishSavingWithError:contextInfo:", nil)

我刚刚根据上述更改和建议进行了快速测试；应该有一个弹出窗口请求授权访问相册。