Overview button switches activity

Question

I have 2 activities Activity A and Activity B. My app starts in Activity A and I have a button on Activity A that leads to Activity B. When I'm in Activity B, I press the Overview Button(The square button) and select my app. When my app loads up, Activity B is destroyed and it loads up into Activity A instead. What is going on and how do I get it to save my settings and load into Activity B?

By extension i'm having an app that loads into firebase authentication and then operates on a firebase database. How do I save the state of it when the overview button is pressed? Do I need to save anything with firebase authetication or do I just save all the data I need to access and manage the firebase database with that?

I watched a couple videos on it where they are talking about screen rotations and saving states, but there's little information about the overview button.

Thanks, Reinaldo

Answer 1

What about saving the current activity to a value in shared preferences and then checking the value in the onCreate method of activity A. You can have a switch statement that redirects to whichever activity the user was on before.

activity A would look like this:

public class A extends AppCompatActivity {

private String currentActivity;
private final String CURRENT_ACT = "current activity";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SharedPreferences sharedPreferences = getSharedPreferences("shared preferences", MODE_PRIVATE);
    currentActivity = sharedPreferences.getString(CURRENT_ACT, "A");

    switch (currentActivity){
        case "A":
            break;

        case "B":
            Intent intent = new Intent(this, B.class);
            startActivity(intent);
            break;
    }

}

}

and B would look like this:

public class B extends AppCompatActivity {

private String currentActivity;
private final String CURRENT_ACT = "current activity";

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    currentActivity = "B";

    SharedPreferences sharedPreferences = getSharedPreferences("shared preferences", MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(CURRENT_ACT,currentActivity);
    editor.commit();

}

}