Wildcard imports

If we have a bunch of imports from the same package, then to avoid specifying each import individually, we can import the entire package at once using the * operator.

If we have several imports from the same package, then to avoid listing each import on a single line, all the classes and interfaces from a package can be imported at once. This is done using the * operator. For example, the following package declaration would import every class and interface from the com.packt.myproject package:

    import com.packt.myproject.* 

Wildcard imports are especially useful when a large number of helper functions or constants are defined at the top level, and we wish to refer to those without using the name of the package that contains those functions. In the following example, two constants will be defined in one package:

    package com.packt.myproject.constants 
    // define the two constants
    val PI = 3.142 
    val E = 2.178 

To avoid referencing these constants by their FQN, we will import them in the next example:

 package com.packt.myproject
    //import the two constants defined 
    import com.packt.myproject.constants.* 
    //sum the two constants
    fun add() = E + PI 

Notice how the add() function does not need to refer to E and PI using the FQN, but can simply use them as if they were in scope. The wildcard import removes the repetition that would, otherwise, be needed when importing numerous constants.