Kotlin:为空，并且“过载分辨率模糊度"为"0". [英] Kotlin: null and "Overload resolution ambiguity"

问题描述

我想从Kotlin调用重载的Java函数.我想使用 null 作为对重载分辨率有意义的参数.

I want to call a overloaded java-function from Kotlin. I want to use a null for parameter that significant to a overload resolution.

如何为 null 值指定 IntArray 类型?

我不喜欢带有普通类型附加变量的解决方案.

I don't like a solution with additional varibale of common type.

推荐答案

不是将变量强制转换，而是将 null设置为IntArray?，例如:

Instead of a variable just cast it, i.e. null as IntArray?, e.g.:

origImg.data.getSamples(0, 0, origImg.width, origImg.height, 0, null as IntArray?)

请注意，这与Java中的行为相同，在Java中，您还需要强制转换 null ，例如(int [])null ，以调用适当的重载方法.

Note that this is the same behaviour as in Java, where you also needed to cast null, e.g. (int[]) null, to call the appropriate overloaded method.

您可以构建一个函数，为您提供〜类型的 null (如果尚不存在)，并使用以下类型:

You could build a function that gives you a ~typed null (if it doesn't exist yet) with a reified type:

inline fun <reified T>typedNull(): T? = null

并通过以下方式调用它:

and calling it with:

typedNull<IntArray>()

但是再说一次，像IntArray一样为空?我认为很清楚，人们已经知道了.

But then again, null as IntArray? is clear enough I think and people know it already.

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