How to recreate previous activity?

Question

I have a main activity (let's call it A) and a second activity (let's call it B) which's used to change the language of the app. The point is, when I click the button to change the language I also call recreate(); and B changes it language. Until here it's ok. The problem comes when I go back to the main activity (A) and it hasn't updated the language because it hasn't been recreated, so, is there any way to recreate A from B in order to update A?

I use this code to translate the app (eng version example):

public void btnIngles_onClick(View v)
{
    Locale locale = new Locale("en");
    Locale.setDefault(locale);

    Configuration config = new Configuration();
    config.locale = locale;
    this.getApplicationContext().getResources().updateConfiguration(config, null);
    recreate();
}

Answer 1

1) Activity B changes some global settings, accessible via SharedPreferences for example

2) In Activity A do:

@Override
protected void onResume() {
    super.onResume();
    if(didLanguageChange)
      recreate();
}

Problem solved. Activity A will call onResume() since it has switched into a paused state when Activity B came into the foreground.

Answer 2

You need to implement onActivityResult() in your Activity. This link has more information and should be very helpful to you. In a nutshell:

Inside your Activity A, you'll need to create a variable used as a request code, something like this:

private static final int ACTIVITY_B_REQUEST = 0;

And then, in your button's onClick listener, you'll start the activity using an intent and the startActivityForResult() function:

Intent myIntent = new Intent(ActivityA.this, ActivityB.class);
startActivityForResult(myIntent, ACTIVITY_B_REQUEST);

This will start Activity B for you. Whenever Activity B finishes, onActivityResult will be called. You can override it and implement it in whichever way you need, but it may look something like this:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(requestCode == ACTIVITY_B_REQUEST && resultCode == RESULT_OKAY){
        // Handle this by doing what you need to refresh activity A.
    } else{
        super(requestCode, resultCode, data);
    }   
}