java.lang.NumberFormatException: Invalid int: “” : Error

Question

I am doing some calculation but unable to parse a string into int or even in float.I searched for solution and i read it somewhere there must be a empty string but i checked my

Answer 1

you should get the values inside a method so that your app does not try to assign the values immediatly you are creating them check below how am doing it using kotlin

     myresult = findViewById(R.id.txtresult)
     val1 = findViewById(R.id.valone)
     val2 = findViewById(R.id.valtwo)

after getting the field use method as below

    fun calculate() : Int {

        var value1 = Integer.parseInt(val1.text.toString())
        var value2 = val2.text.toString().toInt()
        var result : Int

        when (opType){

            "+" ->{result = value1 + value2
                    return result
                 }
            "-" ->{result = value1 - value2
                return result
            }
            "*" -> {result = value1 * value2
                return result
            }
            "/" -> {result = value1 / value2
                return result
            } else -> result = 20

        }

        return result
    }

     btn.setOnClickListener{

        println(calculate().toString())
        myresult.text = calculate().toString()


    }

for those moving to kotlin and finding the same error I hope this code will help you