how to make non-repeating random array selection (android)?

Question

i have a problem in randomizing values. what i want to do is :

i have 4 editFields and when i type in all fields and click the button "shuffle players" it should show all the players from editFields down in viewText below randomly and non-repeated.

this my code for onlick function:

 public void RandomPlayers(View v1){


    EditText text1 = (EditText)findViewById(R.id.editText1);
    TextView View1 = (TextView)findViewById(R.id.player1);
    EditText text2 = (EditText)findViewById(R.id.editText2);
    TextView View2 = (TextView)findViewById(R.id.player2);
    EditText text3 = (EditText)findViewById(R.id.editText3);
    TextView View3 = (TextView)findViewById(R.id.player3);
    EditText text4 = (EditText)findViewById(R.id.editText4);
    TextView View4 = (TextView)findViewById(R.id.player4);

    String value1 = text1.getText().toString();
    String value2 = text2.getText().toString();
    String value3 = text3.getText().toString();
    String value4 = text4.getText().toString();

    String[] players = {value1, value2, value3, value4};

    int index = new Random().nextInt(players.length);
    String random = (players[index]);
    View1.setText(random);
    View2.setText(random);
    View3.setText(random);
    View4.setText(random);

}

but the problem i keep getting the same random name for all Textviews

and here is an image showing the logic error: ![enter image description here][1]

please help me and show me my mistakes thanks

See @ZouZou's answer here: http://stackoverflow.com/a/16724116/2649012 — Phantômaxx, May 12 '14 at 09:06

score 3 · Accepted Answer · answered May 12 '14 at 09:07

Try this solution works like a charm

public void RandomPlayers(View v1) {

        List<String> values = new ArrayList<String>();

        EditText text1 = (EditText) findViewById(R.id.editText1);
        TextView View1 = (TextView) findViewById(R.id.player1);
        EditText text2 = (EditText) findViewById(R.id.editText2);
        TextView View2 = (TextView) findViewById(R.id.player2);
        EditText text3 = (EditText) findViewById(R.id.editText3);
        TextView View3 = (TextView) findViewById(R.id.player3);
        EditText text4 = (EditText) findViewById(R.id.editText4);
        TextView View4 = (TextView) findViewById(R.id.player4);

        values.add(text1.getText().toString());
        values.add(text2.getText().toString());
        values.add(text3.getText().toString());
        values.add(text4.getText().toString());

        Collections.shuffle(values);

        View1.setText(values.get(0));
        View2.setText(values.get(1));
        View3.setText(values.get(2));
        View4.setText(values.get(3));

    }

Thank you Biraj for great solution. (Y) I have your contact. You may know me. Nice to see you here. — Pratik Butani, Aug 30 '18 at 10:18

score 0 · Answer 2 · edited May 23 '17 at 12:21

0

You only generate one random number, so the index is always the same and you only get one name in all your TextViews. You could shuffle your array like explained here and get all the names from it and bind them to your TextViews.

edited May 23 '17 at 12:21

Community

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1

answered May 12 '14 at 09:05

Joris

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score 0 · Answer 3 · answered May 12 '14 at 09:05

0

You are setting the same random values for all your views meaning that you pick the random once and then assign it you should do something similar but before each assignment call random again

answered May 12 '14 at 09:05

royB

12,779
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score 0 · Answer 4 · answered May 12 '14 at 09:07

Change

int index = new Random().nextInt(players.length);
String random = (players[index]);
View1.setText(random);
View2.setText(random);
View3.setText(random);
View4.setText(random);

to

int index = new Random().nextInt(players.length);
String random = (players[index]);
View1.setText(random);

index = new Random().nextInt(players.length);
random = (players[index]);
View2.setText(random);

index = new Random().nextInt(players.length);
random = (players[index]);
View3.setText(random);

index = new Random().nextInt(players.length);
random = (players[index]);
View4.setText(random);

This way you get different numbers but there is no guarantee that there will be no repitition

how to make non-repeating random array selection (android)?

4 Answers4