Mastering Android Development with Kotlin

Your first screen

We created an application with no screens. We will not waste time, we will create one! Create a new package named activity where all our screen classes will be defined, and create your first Activity class named MainActivity.kt. We will start with one simple class:

    package com.journaler.activity 
 
    import android.os.Bundle 
    import android.os.PersistableBundle 
    import android.support.v7.app.AppCompatActivity 
    import com.journaler.R     class MainActivity : AppCompatActivity() { 
      override fun onCreate(savedInstanceState: Bundle?,      persistentState: PersistableBundle?) { 
        super.onCreate(savedInstanceState, persistentState) 
        setContentView(R.layout.activity_main) 
      } 
    } 

Soon, we will explain the meaning of all these lines. For now, it's important ...