java - Can't get selected spinner item outside @Override method and into another class

Question

I have MainActivity and SpinnerActivity, I want to get selected spinner item value from SpinnerActivity into the MainActivity. I tried to declare String as Static, I also tried with getter but without any success.

in Spinner Activity I also have if statement, how can I get value outside "if statement" and "@Override method" into another class?

MainActivity.class

public class MainActivity extends AppCompatActivity {

    SpinnerActivity spinnerActivity = new SpinnerActivity();

    Spinner spinnerProvince;

    String selectedSpinnerProvince = spinnerActivity.inSpinnerSelectedProvince;
//    String selectedSpinnerProvince = SpinnerActivity.inSpinnerSelectedProvince;


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

        spinnerProvince = findViewById(R.id.spinnerProvince);

        populateSpinnerProvinces();

        spinnerProvince.setOnItemSelectedListener(spinnerActivity);

    }

    public void populateSpinnerProvinces() {
        ArrayAdapter<String> provincesAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.province));
        provincesAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinnerProvince.setAdapter(provincesAdapter);
    }
}

SpinnerActivity.class

public class SpinnerActivity implements android.widget.AdapterView.OnItemSelectedListener {

    public String inSpinnerSelectedProvince;


    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

        if (parent.getId() == R.id.spinnerProvince) {

            inSpinnerSelectedProvince = parent.getItemAtPosition(position).toString();
            Toast.makeText(parent.getContext(), parent.getItemAtPosition(position).toString(), Toast.LENGTH_SHORT).show();

        } else {// code here}
        
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

Answer 1

I were about to advice you to use Intent to share data between both activities when i noticed that your "SpinnerActivity" is not really an Activity since it not extends Android Activity class (AppCompactActivity or other classes like this).

Your SpinnerActivity is a Listener. You can use it to implement the action to trigger when an action is performed on your Spinner view. For that you need to do it inside the "@Override" method of onItemSelected.

If you don't like to use the previous methode because of the Override methode you should implement directly the action to trigger at on click events on your spinner view in your MainActivity by doing this:

     public class MainActivity extends AppCompatActivity {

      SpinnerActivity spinnerActivity = new SpinnerActivity();

      Spinner spinnerProvince;

       String selectedSpinnerProvince = spinnerActivity.inSpinnerSelectedProvince;
       //    String selectedSpinnerProvince = 
       SpinnerActivity.inSpinnerSelectedProvince;


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

        spinnerProvince = findViewById(R.id.spinnerProvince);

        populateSpinnerProvinces();
         
        //spinnerProvince.setOnItemSelectedListener(spinnerActivity);
     spinnerProvince.setOnItemSelectedListener(android.widget.AdapterView.OnItemSelectedListener() {
         @Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

    if (parent.getId() == R.id.spinnerProvince) {

        inSpinnerSelectedProvince = parent.getItemAtPosition(position).toString();
        Toast.makeText(parent.getContext(), parent.getItemAtPosition(position).toString(), Toast.LENGTH_SHORT).show();

    } else {// code here}
    
}

@Override
public void onNothingSelected(AdapterView<?> parent) {

}
    });

    }

    public void populateSpinnerProvinces() {
        ArrayAdapter<String> provincesAdapter = new ArrayAdapter<>(this, 
     android.R.layout.simple_spinner_item, 
     getResources().getStringArray(R.array.province)); 
  
 provincesAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinnerProvince.setAdapter(provincesAdapter);
      }
   }