Shuffling an Array in Android

问题

I am very new to Programming and am trying to make a program that takes a number from an EditText then generates and Array which is then shuffled and the shuffled numbers come out on toast. This is what my code looks like. I have tried reading through a number of other posts on shuffling arrays but I haven't been able to get this to work.

public class Home extends Activity  {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);


        final EditText editText1 = (EditText) findViewById(R.id.editText1);  
        Button  goButton = (Button) findViewById(R.id.goButton);
        goButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                String no = editText1.getText().toString();
                int no2 = Integer.parseInt(no);

                int[] integerArray = new int[no2];
                for (int i = 0; i < no2; i++)  
                    integerArray[i] = i;

                Collections.shuffle(Arrays.asList(integerArray));
                {



                    Toast msg= Toast.makeText(getApplicationContext(),  integerArray[no2], Toast.LENGTH_LONG);

                    msg.show();
                }

            }
        });
    }
}

Thank you in advance for any help. Tom

回答1:

Actually you don't use the array that you shuffled, but the integer array that you created. Try instead :

List<Integer> myArray = new ArrayList<Integer>(Arrays.asList(integerArray));
Collections.shuffle(myArray);

And then

Toast msg= Toast.makeText(getApplicationContext(),  myArray.get(no2-1), Toast.LENGTH_LONG);
msg.show();

Another better approach would be to directly create the List.

 List<Integer> myArray = new ArrayList<Integer>(no2);
            for (int i = 0; i < no2; i++)  
                myArray.add(i);

        Collections.shuffle(myArray);

来源：https://stackoverflow.com/questions/16724084/shuffling-an-array-in-android

标签

java

android

arrays

shuffle