val k = " asdfasdf "
fun test() {
if(k is String) {
// Do something
}
}
So, how do I pass that String through the function calls eg:
fun test(xxxx) {
if(k is xxxx) {
// do something
}
}
Add a comment
|
4 Answers
Like this:
inline fun <reified T> testType(k: Any) {
if(k is T) {
println("is a ${T::class.simpleName}")
} else {
println("is not a ${T::class.simpleName}")
}
}
Call it like this:
test<String>("Hello") // is a String
test<String>(1) // is no String
Here some further reading.
Comments
There are two possibilities, depending on your needs.
1. Use inline and a reified type parameter
You can use the reified keyword on the type parameter in combination with an inline function:
inline fun <reified T> test(k: Any) {
if (k is T) {
println("k is a T!")
}
}
See the documentation on reified.
2. Use KClass<T>
If you do not want to or cannot make your function inline you can use a KClass parameter:
fun <T : Any> test(k: Any, type: KClass<T>) {
if (type.isInstance(k)) {
println("k is a T!")
}
}
Comments
You can either use a predicate, e.g.:
fun testIt(predicate: (Any?) -> Boolean) {
if (predicate(k)) {
println("matches!")
} else println("nope")
}
and call it as follows:
testIt { it is String }
testIt { it is Int }
Or you can use a reified type:
inline fun <reified T> testIt() {
when (k) {
is T -> println("matches!")
else -> println("nope")
}
}
and call it like:
testIt<String>()
testIt<Int>()
For simplicity I kept your current variable inside the testIt-method... you may want to redesign that ;-)
I basically assumed a member variable as follows: var k : Any? = null
Comments
inline fun <reified T> isType(obj: Any): Boolean {
return obj is T
}
fun main(args: Array<String>) {
val test = "This is a String"
if (isType<String>(test)) {
println("Success")
} else {
println("Failure")
}
}
