Swapping of Spinners

Question

My app consists of two spinners and one button, i have selected each value from each spinner, later i had swapped the spinner adapters using button click, when spinner adapters are modified, the result by default represents initial values, no matter what ever values i have given.

This is how my MainActivity looks like

public class MainActivity extends AppCompatActivity {

private Spinner alphabets, numbers;
private Button swapSpinners;
private ArrayAdapter<CharSequence> alphabetsAdapter, numbersAdapter;

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

    alphabets = (Spinner) findViewById(R.id.alphabets);
    numbers = (Spinner) findViewById(R.id.numbers);
    swapSpinners = (Button) findViewById(R.id.swapSpinner);


    alphabetsAdapter = ArrayAdapter.createFromResource(this,
            R.array.alphabets, android.R.layout.simple_spinner_item);
    alphabetsAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    alphabets.setAdapter(alphabetsAdapter);

    numbersAdapter = ArrayAdapter.createFromResource(this,
            R.array.numbers, android.R.layout.simple_spinner_item);
    numbersAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    numbers.setAdapter(numbersAdapter);

    swapSpinners.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (alphabets.getAdapter().equals(alphabetsAdapter)) {
                alphabets.setAdapter(numbersAdapter);
                numbers.setAdapter(alphabetsAdapter);
            } else {
                alphabets.setAdapter(alphabetsAdapter);
                numbers.setAdapter(numbersAdapter);
            }
        }
    });}
}

This is how my activity_main looks like

<?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="karthik.spinnerswap.MainActivity">

<Spinner
    android:id="@+id/alphabets"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<Button
    android:id="@+id/swapSpinner"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/alphabets"
    android:text="Swap Spinners" />
<Spinner
    android:id="@+id/numbers"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/swapSpinner" />
  </RelativeLayout>

This is how my strings.xml looks like

<resources>
<string name="app_name">SpinnerSwap</string>

<string-array name="alphabets">
    <item>A</item>
    <item>B</item>
    <item>C</item>
    <item>D</item>
    <item>E</item>
    <item>F</item>
    <item>G</item>
    <item>H</item>
    <item>I</item>
    <item>J</item>
</string-array>

<string-array name="numbers">
    <item>0</item>
    <item>1</item>
    <item>2</item>
    <item>3</item>
    <item>4</item>
    <item>5</item>
    <item>6</item>
    <item>7</item>
    <item>8</item>
    <item>9</item>
</string-array>

Selecting values, before swapping the spinners

spinners after swapping

I need to show the selected values after swapping the spinners

Answer 1

Use this it solve your problem .

swapSpinners.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
          int positionSpinner1 = alphabets.getSelectedItemPosition() ;
          int positionSpinner2 = numbers.getSelectedItemPosition() ;
          if (alphabets.getAdapter().equals(alphabetsAdapter)) {
            alphabets.setAdapter(numbersAdapter);
            numbers.setAdapter(alphabetsAdapter);
            } else {
            alphabets.setAdapter(alphabetsAdapter);
            numbers.setAdapter(numbersAdapter);
            }
          alphabets.setSelection(positionSpinner2);
          numbers.setSelection(positionSpinner1);
        }
    });

Note:-Use int position to interchange their values.....

Answer 2

To add some explaination to the accepted answer; setting the adapter resets the spinner to the first item of its list (because it inflates the list all over again), therefore you have to manually save the selected item and restore it after swapping the adapters.