ios - 如何将数组转换为 UnsafeMutablePointer Swift 3.0？

Question

这是我在以前版本的 Swift 中的可行代码:

 let imageOptionsDictKeys = [ kCVPixelBufferPixelFormatTypeKey, kCVPixelBufferWidthKey,  kCVPixelBufferHeightKey, kCVPixelBufferOpenGLESCompatibilityKey, kCVPixelBufferIOSurfacePropertiesKey]
 let imageOptionsDictValues = [ cvPixelFormatType,  frameW, frameH, boolYES]

 var keyCallbacks = kCFTypeDictionaryKeyCallBacks
 var valueCallbacks = kCFTypeDictionaryValueCallBacks

 let imageOptions = CFDictionaryCreate(kCFAllocatorDefault, UnsafeMutablePointer(imageOptionsDictKeys), UnsafeMutablePointer(imageOptionsDictValues), 4, &keyCallbacks, &valueCallbacks)

在 Swift 3.0 发生变化后，我必须将我的键和值数组转换为 UnsafeMutablePointer<UnsafeRawPointer?>用于创建 CFDictionary。

这样:

    let imageOptionsDictKeysPointer =  UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: 1)
    imageOptionsDictKeysPointer.initialize(to: imageOptionsDictKeys)

给出错误访问错误。

在阅读文档后，我正在尝试编译这段代码:

        let imageOptionsDictKeys = [kCVPixelBufferPixelFormatTypeKey, kCVPixelBufferWidthKey,  kCVPixelBufferHeightKey, kCVPixelBufferOpenGLESCompatibilityKey]
        let imageOptionsDictKeysRawPointer = Unmanaged.passUnretained(imageOptionsDictKeys).toOpaque()
        let imageOptionsDictKeysPointer =  UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: 1)
        imageOptionsDictKeysPointer.initialize(to: imageOptionsDictKeysRawPointer)

        let imageOptionsDictValues = [ cvPixelFormatType,  frameW, frameH, boolYES]
        let imageOptionsDictValuesRawPointer = Unmanaged.passUnretained(imageOptionsDictValues).toOpaque()
        let imageOptionsDictValuesPointer =  UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: 1)
        imageOptionsDictValuesPointer.initialize(to: imageOptionsDictValuesRawPointer)

        let imageOptions = CFDictionaryCreate(kCFAllocatorDefault, imageOptionsDictKeysPointer, imageOptionsDictValuesPointer, 4, &keyCallbacks, &valueCallbacks)

但错误Generic parameter 'Instance' could not be inferred 出现在 Unmanaged.passUnretained(array).toOpaque() 行中/p>

我现在不知道如何以编程方式创建 CFDictionary。

Answer 1

我刚刚解决了将数组转换为 UnsafeMutablePointer< UnsafeMutablePointer<T>> 的类似问题你可以在这里找到: Swift 3 UnsafeMutablePointer initialization for C type float**

要使用相同的方案转换 swift 数组，请使用 UnsafeMuTablePointer如此处所建议:http://technology.meronapps.com/2016/09/27/swift-3-0-unsafe-world-2/