How to retain value in second activity after re-clicking the button from MainActivity to launch the second activity?

Question

I have 2 activities. First is MainActivity and second is SecondActivity .

MainActivity has a textView and button called "Launch". Using intent and startActivityForResult I am passing a list to SecondActivity .

SecondActivity has a spinner and 2 buttons ;a select button and a cancel button.

On selection of an item from the spinner , when user clicks on Select button, the option chosen in the spinner is populated in the textView of MainActivity .

Now when the user again clicks on "Launch", SecondActivity launches however, the spinner doesn't hold the value the user had chosen last time, instead it shows the first value of the spinner .

Is their anyway, how I can retain the value selected in the SecondActivity chosen by the user in it's previous use.

Answer 1

You can persist information using SharedPreferences, just store the last selection from the user and then retrieve it to set on SecondActivity.

Context context = getActivity();
SharedPreferences prefs = context.getSharedPreferences(
        getString("myPreferences"), Context.MODE_PRIVATE);

//Store a value
SharedPreferences.Editor editor = prefs.edit();
editor.putString("selection","foo");

//Get the value
String selection = prefs.getString("selection", "defaultOption");

Here is the official documentation: https://developer.android.com/training/data-storage/shared-preferences

Answer 2

When you close the SecondActivity, you should return the select item of spinner to MainActivity. If it is MainActiviy can get that value in this function:

        onActivityResult(int requestCode, int resultCode,  @Nullable Intent data)

before that, you shold show SecondActivity with

       startActivityForResult(intent, SECOND_CODE);

so the code can be like this

        private static SECOND_CODE = 1001;

        Intent intent = new Intent(MainActivity.this, SecondActivity.class); 
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivityForResult(intent, SECOND_CODE);
                

         @Override
         protected void onActivityResult(int requestCode, int resultCode,  @Nullable Intent data) {
              super.onActivityResult(requestCode, resultCode, data);
              if (requestCode == SECOND_CODE && resultCode == 
                    Activity.RESULT_OK && data != null) {
                 // you can get selected spinner item here
              }
          }

After that, when you want to show SecondActivity again

        Intent intent = new Intent(MainActivity.thisSecondActivity.class); 
        intent.putExtra("selected_spinner", /*the spinner item you got from above function*/)
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivityForResult(intent, SECOND_CODE);

and in SecondActivity, you can get the selected spinner item from getIntent()

        String selected_spinner = getIntent().getStringExtra("selected_spinner");

Then you can find this string in Spinner and select it.