How to add data in array on button click?

Question

    int size = mcq.size();


    String arr[] = null;
    int i;
    {


        for (i = 0; i < size; i++) {


            if (op1.isPressed()) {
                arr[i] = tv1.getText().toString();
                // Log.e("Array",arr[i]);

            } else if (op2.isPressed()) {
                arr[i] = tv2.getText().toString();
                //Log.e("Array",arr[i]);

            } else if (op3.isPressed()) {
                arr[i] = tv3.getText().toString();
                //  Log.e("Array",arr[i]);


            } else if (op4.isPressed()) {
                arr[i] = tv4.getText().toString();
                //Log.e("Array",arr[i]);


            }

I am trying to store the data in an array when the button is pressed,but it always shows null.And when the for loop is over I want to display my array.

the problem in ArrayList is that it adds the duplicate value@ndeokar — T.S
– T.S, Commented May 11, 2016 at 6:08
Ok,if I clicked op1,op2,op3 and op4 then it will add all the data for the same position,which I don, not want.For a position I want only one value.So can u tell me if it solves the problem I will use it @ndeokar — T.S
– T.S, Commented May 11, 2016 at 6:12

User Learning · Accepted Answer · 2016-05-11 06:31:37Z

2

here , Arrays in Java have a size so u cannot do like this. Instead of this use list,

ArrayList<String> arr = new ArrayList<String>();

Inorder to do using String array :

String[] arr = new String[SIZEDEFNE HERE];

For ur answer :

ArrayList<String> arr = new ArrayList<String>();
    int i;
        {
            for (i = 0; i < size; i++) {
                if (op1.isPressed()) {
                    arr.add(tv1.getText().toString()); 
                } else if (op2.isPressed()) {
                    arr.add(tv2.getText().toString()); 

                } else if (op3.isPressed()) {
                    arr.add(tv3.getText().toString()); 

                } else if (op4.isPressed()) {
                    arr.add(tv4.getText().toString()); 
                }

Retrive value using

String s = arr.get(0);

answered May 11, 2016 at 6:31

User Learning

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Comments

jayeshsolanki93 · Accepted Answer · 2016-05-11 06:10:27Z

1

This is because your string array is null. Declare it with the size as

String[] arr = new String[size];

answered May 11, 2016 at 6:10

jayeshsolanki93

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2 Comments

T.S Over a year ago

Still getting null

jayeshsolanki93 Over a year ago

You may have not initialized your TextView's (tv1, tv2, tv3, tv4) properly.

user5248371 · Accepted Answer · 2016-05-11 06:24:06Z

1

Try Array List. use the following code in your main java

final ArrayList<String> list = new ArrayList<String>();

Button button= (Button) findViewById(R.id.buttonId);
final EditText editText = (EditText) findViewById(R.id.editTextId)
button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        list.add(editText.getText().toString());
    }
});

answered May 11, 2016 at 6:24

user5248371

Comments

Amit Ranjan · Accepted Answer · 2016-05-11 06:13:35Z

0

To avoid duplication in arraylist .You can use arraylist for faster then String array

ArrayList<String> list = new ArrayList<String>();
    list.add("Krishna");
    list.add("Krishna");
    list.add("Kishan");
    list.add("Krishn");
    list.add("Aryan");
    list.add("Harm");

System.out.println("List"+list);
HashSet hs = new HashSet();
hs.addAll(list);
list.clear();
list.addAll(hs);

answered May 11, 2016 at 6:13

Amit Ranjan

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