Changing the locale of the Navigation drawer items and fragment Activities

Question

When I change the locale of the app, every TextView changes the language but fragment activities(activities opened from fragment) and navigation drawer items don't change the language. Have a look at this Multiple Language for code reference.

The problem is after locale change, only fragments language is changing. I searched over the internet but found no reasonable answer please guide me how to solve this issue?

Answer 1

Let suppose language change settings is from MainActivity. And so get Navigation Drawer menu item from NavigationView and initViews() within onCreate().

    Menu menu = navigationView .getMenu();
    View headerView = navigationView.getHeaderView(0);
    txt_nav_header_name = headerView.findViewById(R.id.txt_nav_header_name);

After that we call loadLocale() for language change and update Strings Values within onCreate(). See here:

  public void changeLang(String lang){
    if (lang.equalsIgnoreCase(""))
        return;
    myLocale = new Locale(lang);
    saveLocale(lang);
    Locale.setDefault(myLocale);
    android.content.res.Configuration config = new android.content.res.Configuration();
    config.locale = myLocale;
    getBaseContext().getResources().updateConfiguration(config, getBaseContext().getResources().getDisplayMetrics());
    updateTexts();
}

public void saveLocale(String lang){
    String langPref = "Language";
    SharedPreferences prefs = getSharedPreferences("CommonPrefs", Activity.MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    editor.putString(langPref, lang);
    //  editor.commit();
    editor.apply();
}

public void loadLocale(){
    String langPref = "Language";
    SharedPreferences prefs = getSharedPreferences("CommonPrefs", Activity.MODE_PRIVATE);
    String language = prefs.getString(langPref, "");
    changeLang(language);
}

private void updateTexts() {
    languageUpdate();
}

private void languageUpdate() {
    txt_app_name.setText(getString(R.string.app_name));
    if (actionBar != null){
        actionBar.setTitle(getString(R.string.app_name));
    }
    toolbar.setTitle(getString(R.string.app_name));

    txt_nav_header_name.setText(getString(R.string.app_name));
    // txt_nav_header_name.setTypeface(tf_mm); // for embedded font
    for (int i=0;i<menu.size();i++) {
        MenuItem mi = menu.getItem(i);
        int id = mi.getItemId();
        if (id == R.id.nav_home){
            mi.setTitle(getString(R.string.home));
        }
        else if (id == R.id.nav_history){
            mi.setTitle(getString(R.string.history));
        }
        else if (id == R.id.nav_aboutus){
            mi.setTitle(getString(R.string.about));
        }
        else if (id == R.id.nav_guide){
            mi.setTitle(getString(R.string.guide));
        }
        label= new String[] {getString(R.string.farmer), getString(R.string.merchant), getString(R.string.news), getString(R.string.videos)};
        grid.setAdapter(new CustomGrid(this,label,image));
    }
}

In your onOptionsItemSelected(MenuItem menuItem) method, call language change method. See here:

  @Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    String lang;
    if(id == R.id.action_lang_en_settings){
        lang = "en";
        changeLang(lang);
        return true;
    }
    else if(id == R.id.action_lang_mm_settings){
        lang = "my";            
        changeLang(lang);
        return true;
    }
    return super.onOptionsItemSelected(item);
}

In Fragment or Activity, call loadLocale() and update views in languageUpdate(). I hope this will solve yours.