MainActivity.kt

class MainActivity : AppCompatActivity() {
    val data: ArrayList<PageModel> = ArrayList()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        prepareData()
        prepareViewPager()
    }

    private fun addData(message:String, color:Int){
        data.add(PageModel(message, color))
    }

    private fun prepareData() {
        addData("I'm Angry >:(", android.R.color.holo_red_dark)
        addData("I'm sad :'(", android.R.color.holo_blue_dark)
        addData("I'm happy :D", android.R.color.holo_green_dark)
    }

    private fun prepareViewPager() {
        vp_main.adapter = VPMainAdapter(data)
    }
}