Best practices while handling android application lifecycle.

 Saving Instances of Android App 

• onSaveInstanceState is a callback where you could save data that you might need in case the Android OS destroys your app.
• onSaveInstanceState is called after the app goes in state onStop (Note* after API 28 )
• Best practice to keep this data in Bundle small while we save, generally we should store maximum of 100 KB otherwise the app will crash. 

Use Case:

• save required data in onSaveInstanceSate bundle as key_value pair 
• recover the data in onRestoreInstanceState or onCreate with it's bundle  
• Change the orientation of screen and check if the saved instance works 

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    if (savedInstanceState!= null){
        amount = savedInstanceState.getInt(AMOUNT_KEY)
    }
}

override fun onStop() {
    super.onStop()
    Timber.i("onStop called")
}

override fun onSaveInstanceState(outState: Bundle) {
    super.onSaveInstanceState(outState)
    outState.putInt(AMOUNT_KEY, amount)
    Timber.i("onSaveInstanceState called")
}

Note that : onRestoreInstanceState is called after onStart 

override fun onRestoreInstanceState(savedInstanceState: Bundle) {
    super.onRestoreInstanceState(savedInstanceState)
}