英文:
Pass a static method as a parameter to another method in Kotlin
问题
根据这个问题，可以将一个函数作为参数传递给另一个函数，如下所示
fun foo(m: String, bar: (m: String) -> Unit) {
bar(m)
}
fun buz(m: String) {
println("another message: $m")
}
fun something() {
foo("hi", ::buz)
}
同样，我们也可以传递来自类的方法
class OtherClass {
fun buz(m: String) {
println("another message: $m")
}
}
foo("hi", OtherClass()::buz)
但是，如果我们要传递的方法是静态的（在伴生对象内部）呢？
class OtherClass {
companion object {
fun buz(m: String) {
println("another message: $m")
}
}
}
我知道由于它是静态的，我们可以直接调用该方法，而不必将其作为参数传递，但是仍然存在一些情况（例如在利用现有代码时），这将会很有用。
英文:
As per this question, a function can be passed as a parameter to another function as shown below
fun foo(m: String, bar: (m: String) -> Unit) {
bar(m)
}
fun buz(m: String) {
println("another message: $m")
}
fun something() {
foo("hi", ::buz)
}
Similarly, we can also pass a method from a class
class OtherClass {
fun buz(m: String) {
println("another message: $m")
}
}
foo("hi", OtherClass()::buz)
But what if the method we want to pass is static (within a companion object)?
class OtherClass {
companion object {
fun buz(m: String) {
println("another message: $m")
}
}
}
I am aware that since it is static we can simply call the method directly without having to resort to passing it as a parameter, however, there are still some situations (such as when taking advantage of pre-existing code) where this would be useful.
答案1
得分: 3
访问类的伴生对象使用 ${className}.Companion。所以...
foo("hit", OtherClass.Companion::buz)。
英文:
To access companion object of class use ${className}.Companion. So...
foo("hit", OtherClass.Companion::buz).
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