How to close activity with old preferences data?

Question

I am developing an android app with preferences. I have 2 activities: MainActivity and PrefActivity. At MainActivity I am show textview with value from preferences. At PrefActivity I change this value from ListPreference. When i press back button in the PrefActivity, it is refer me to the MainActivity with text of new value from preferences. But if i press back button once more, then it refer me to the old MainActivity with text of old value from preference. How I can escape from the old MainActivity? Code of retrieve value from preferences:

sp = PreferenceManager.getDefaultSharedPreferences(this);
String sharedpreferences = sp.getString("sharedpreference", "");
TextView tv_info = findviewbyid(R.id.tvinfo);
tv_info.settext(sharedpreferences);

Answer 1

Kindly check the below logic and implement.

Your MainActivity

if (id == R.id.action_settings) { 
Intent intent = new Intent(MainActivity.this, PrefActivity.class); 
intent.putExtra("fwflag","from_menu_item"); 
startActivity(intent);
}

Remove your implementation of setting data from the shared preference from oncreate method, and paste it to the onResume method:

@Override
public void onResume() {
    super.onResume();
sp = PreferenceManager.getDefaultSharedPreferences(this);
String sharedpreferences = sp.getString("sharedpreference", "");
TextView tv_info = findviewbyid(R.id.tvinfo);
tv_info.settext(sharedpreferences);
}

Then in your PrefActivity

update the below code - remove onbackpressed() and put finish().

toolbar.setNavigationOnClickListener(new View.OnClickListener() { 
@Override 
public void onClick(View v) { 
finish(); 
} 

Under PrefFragment

remove the below code

Intent intent = new Intent(PrefActivity.this, MainActivity.class); 
startActivity(intent); 

and just put

finish(); 

and now try.

Let me know for queries.