How to add values to array and getback in java?

Question

How do i add the value of numOne given below to an array so that when i need a before value i can take from that array. On every time i click operator i need to store the value in array before resetting number.

public void onClickOperator(View v){
    Button op = (Button) v;
        if (stxtOutput != "") {
            if (!opt) {
                if (current_operator == "") {
                    stxtInput += op.getText();
                    num1 = "";
                    numOne = 0.0;
                    Result = pt;
                    stxtOutput = format.format(pt);
                    current_operator += op.getText().toString();
                    opt = true;
                    decimal = false;
                    update();

i have tried to add but got error,

ArrayList<Double> numb;
numb = new ArrayList<>();
numb.add(numOne);

and if the last value stored numb.add(i) i need to get the value of before value i-1

What kind of error are you getting and can you please elaborate your problem in more detailed way? — Vignesh T I, Apr 16 '20 at 18:19
What is the error that you are getting when u store in inside numb arraylist? What is the datatype of numOne? — Vignesh T I, Apr 16 '20 at 18:25
Note that you are comparing strings with `==`. That is a problem on its own. See [How do I compare strings in Java](https://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — MC Emperor, Apr 16 '20 at 18:27
Double data type. app crashes on getting value from optr.get(i). i think i need to use for loop but dont know how to use to add and get data — Ajay Vaidhyanathan, Apr 16 '20 at 18:28
@MCEmperor That works completely fine without any error my problem is that i need to add the value of numOne to array onClickoperator and i need to get previous and previous numbers — Ajay Vaidhyanathan, Apr 16 '20 at 18:30
@AjayVaidhyanathan, do you create your array list each time before adding the `numOne`? — Nowhere Man, Apr 16 '20 at 19:07
You mentioned _app crashes on getting value from optr.get(i)_ Will you provide a code referring this variable `optr` ? — Nowhere Man, Apr 16 '20 at 19:10
@AjayVaidhyanathan Maybe in your case, but that's coincidence. — MC Emperor, Apr 16 '20 at 19:44

How to add values to array and getback in java?

0 Answers0