Qfyilyi

I am learning Java / Kotlin and tried to write a simple calculator app. Everything works up until the point here I press enter to get my answer. I implemented two display functions numberDisplay. one that displays the user inputs to a textview and one that displays the answer to the same textview after the user presses enter. However, the answer the doesn't display. If i remove the second display function and stick to just one (the one that takes an array) it works. but it won't work with the second function that takes a string. I just doesn't display for some reason. I know there are probably better ways to do this, but I want to figure out why the overloading won't work.

package com.zzz.yyy.xx



import android.graphics.Color

import android.support.v7.app.AppCompatActivity

import android.os.Bundle

import android.view.View

import android.widget.Button

import kotlinx.android.synthetic.main.activity_main.*

import kotlin.collections.ArrayList



class MainActivity : AppCompatActivity() {



    override fun onCreate(savedInstanceState: Bundle?) {

        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)



        }



    var displayList = arrayListOf<String>()



    fun buttEvent(view:View){

        val butt = view as Button

        var buttID:String = "0"



        when(butt.id){

            button13.id-> buttID ="C"

            button14.id-> buttID ="D"

            button15.id-> buttID ="/"



            button16.id-> buttID ="8"

            button17.id-> buttID ="9"

            button18.id-> buttID ="X"

            button7.id-> buttID ="7"



            button19.id-> buttID ="5"

            button20.id-> buttID ="6"

            button21.id-> buttID ="-"

            button6.id-> buttID ="4"



            button22.id-> buttID ="1"

            button23.id-> buttID ="2"

            button24.id-> buttID ="3"

            button25.id-> buttID ="+"



            button26.id-> buttID ="0"

            button27.id-> buttID ="."

            button28.id-> buttID ="="

            button29.id-> buttID ="N"

            else-> buttID="null"

        }



        if(buttID == "D"){

            displayList.removeAt(displayList.count()-1)

        } else if (buttID == "C"){

            displayList.clear()

        }else if (buttID== "="){

            equals(displayList)

        }else{

            displayList.add(buttID)

        }

        numberDisplay(displayList)



    }



    fun equals(xthings:ArrayList<String>){

        var operation = ""

        var temp= ArrayList<String>()

        var indexoperation = 0

        var finalnumber= xthings.count()

        var answer:String = ""



        for (thing in xthings) {

            if (thing == "X" || thing == "-" || thing == "+" || thing == "/") {

                indexoperation = xthings.indexOf(thing)

                operation = thing

            }

        }

        temp= xthings.joinToString("").split(operation) as ArrayList<String>





        when(operation){

            "X"-> answer= (temp[0].toInt() * temp[1].toInt()).toString()

            else-> answer = "null"

        }



        numberDisplay(answer)

    }



    fun numberDisplay(arr:ArrayList<String>){

        val outputString:String = arr.joinToString("")

        showNumbers.text = outputString

    }



    fun numberDisplay(texts:String){

        showNumbers.text = texts

    }



}

I am probably missing something obvious, but I can't figure out what

edit:
I made it work by adding a second onclick event. using a new one for the equal button
here is the new code

class MainActivity : AppCompatActivity() {



    override fun onCreate(savedInstanceState: Bundle?) {

        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)



        }



    var displayList = arrayListOf<String>()



    fun buttEvent(view:View){

        val butt = view as Button

        var buttID:String = "0"



        when(butt.id){

            button13.id-> buttID ="C"

            button14.id-> buttID ="D"

            button15.id-> buttID ="/"



            button16.id-> buttID ="8"

            button17.id-> buttID ="9"

            button18.id-> buttID ="X"

            button7.id-> buttID ="7"



            button19.id-> buttID ="5"

            button20.id-> buttID ="6"

            button21.id-> buttID ="-"

            button6.id-> buttID ="4"



            button22.id-> buttID ="1"

            button23.id-> buttID ="2"

            button24.id-> buttID ="3"

            button25.id-> buttID ="+"



            button26.id-> buttID ="0"

            button27.id-> buttID ="."



            button29.id-> buttID ="N"

            else-> buttID="null"

        }



        if(buttID == "D"){

            displayList.removeAt(displayList.count()-1)

        } else if (buttID == "C"){

            displayList.clear()

        }else{

            displayList.add(buttID)

        }

        numberDisplay(displayList)



    }



    fun buttEqual(view: View){



        var operation = ""

        var temp= ArrayList<String>()

        var indexoperation = 0

        var finalnumber= displayList.count()

        var answer:String = ""



        for (thing in displayList) {

            if (thing == "X" || thing == "-" || thing == "+" || thing == "/") {

                indexoperation = displayList.indexOf(thing)

                operation = thing

            }

        }

        temp= displayList.joinToString("").split(operation) as ArrayList<String>





        when(operation){

            "X"-> answer= (temp[0].toInt() * temp[1].toInt()).toString()

            else-> answer = "null"

        }



        numberDisplayx(answer)



    }





    fun numberDisplay(arr:ArrayList<String>){

        val outputString:String = arr.joinToString("")

        showNumbers.text = outputString

    }



    fun numberDisplayx(texts:String){

        showNumbers.text = texts.toString()

    }



}

I still wonder why it did not work the first time

Try to use function with vararg:

fun numberDisplay(vararg texts:String) {

    ...

}

Call it:

var answer:String = ""

numberDisplay(answer)

or

var displayList = arrayListOf<String>()

numberDisplay(*displayList)