MyKotlinExamples.kt

// Singleton pattern - static way to get instance
// Example 1 - Basic
class ExampleClassName {
  // A "companion object" is required to make "static" methods / properites.
  companion object {
    // Property - private stetter, internal getter
    //    @JvmStatic - Only required if used outside of Kotlin
    @JvmStatic lateinit var instance: Context private set
  }
}

// Example 2 - inline - For possible efficiency. (Haven't tested Java output)
class ExampleClassName {
  companion object {
    // Backing variable 
    var mInstance: Context? = null
    // Property with getter
    @JvmStatic val instance: Context? inline get() = mInstance
  }
}

// Example 3 - Create Object instead of class.
object ExampleClassName {
}
// Now ExampleClassName can be used link an instance.
// NOTE: Does not work for if inheriting from the Android Application class
//       Runtime error is thrown due to different constructor.


// An inner class can access the parent instance like the following:
this@ParentClass


// Shorthand for if not null
someVar ?:
  System.out.println("someVar is NOT null")
// This is the same as
if (someVar != null)
  System.out.println("someVar is NOT null")