With Kotlin, specifying a data type is optional.
When using Java, we always had to specify a data type. For example, we couldn't write val name = "Daniel"
but instead were forced to write String name = "Daniel"
. We always had to define the type (String
, in this example).
However, Kotlin does not require a data type. Here's an example. This is valid Kotlin:
val firstName: String = "Daniel"
Notice how we have the String
data type. We can just as easily omit String
:
val firstName = "Daniel"
Kotlin is smart enough to know that firstName
is a String
. We can just as easily provide an Int
:
val age = 25
When you need to specify a data type, sometimes it's enough that the class specifies it's type. Here is an example of a ViewModel
from Android Architecture Components:
val firstName = MutableLiveData<String>()
Kotlin knows that firstName
is now of type MutableLiveData
.
Alert tutorial.
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