Implement multi-language support with language selection screen

app/src/main/java/com/example/updateapp/UpdateApplication.java

@@ -11,4 +11,10 @@ public class UpdateApplication extends Application {
     protected void attachBaseContext(Context base) {
         super.attachBaseContext(LocaleHelper.onAttach(base, "en"));
     }
-}
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        LocaleHelper.applyPersistedLocales(this);
+    }
+}

app/src/main/java/com/example/updateapp/adapters/LanguageAdapter.java

@@ -8,6 +8,7 @@
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
+import androidx.core.content.ContextCompat;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.example.updateapp.R;
@@ -17,9 +18,9 @@
 
 public class LanguageAdapter extends RecyclerView.Adapter<LanguageAdapter.LanguageViewHolder> {
 
-    private Context context;
-    private List<LanguageModel> languageList;
-    private OnLanguageSelectedListener listener;
+    private final Context context;
+    private final List<LanguageModel> languageList;
+    private final OnLanguageSelectedListener listener;
 
     public interface OnLanguageSelectedListener {
         void onLanguageSelected(LanguageModel language, int position);
@@ -41,18 +42,24 @@ public LanguageViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int view
     @Override
     public void onBindViewHolder(@NonNull LanguageViewHolder holder, int position) {
         LanguageModel language = languageList.get(position);
-
         holder.txtLanguageName.setText(language.getLanguageName());
-
-        if (language.isSelected()) {
-            holder.imgSelected.setVisibility(View.VISIBLE);
-        } else {
-            holder.imgSelected.setVisibility(View.GONE);
-        }
+
+        boolean selected = language.isSelected();
+        holder.itemView.setBackgroundResource(
+                selected ? R.drawable.bg_language_item_selected : R.drawable.bg_language_item
+        );
+        holder.imgSelected.setVisibility(selected ? View.VISIBLE : View.INVISIBLE);
+        holder.imgSelected.setContentDescription(
+                selected ? context.getString(R.string.selected_language) : null
+        );
+        holder.txtLanguageName.setTextColor(
+                ContextCompat.getColor(context, selected ? R.color.themeColor : R.color.black)
+        );
+        holder.itemView.setSelected(selected);
 
         holder.itemView.setOnClickListener(v -> {
             if (listener != null) {
-                listener.onLanguageSelected(language, position);
+                listener.onLanguageSelected(language, holder.getBindingAdapterPosition());
             }
         });
     }
@@ -79,4 +86,4 @@ public LanguageViewHolder(@NonNull View itemView) {
             imgSelected = itemView.findViewById(R.id.img_selected);
         }
     }
-}
+}

app/src/main/java/com/example/updateapp/adapters/OnboardingAdapter.java

@@ -8,70 +8,65 @@
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
-import androidx.constraintlayout.widget.ConstraintLayout;
 import androidx.viewpager.widget.PagerAdapter;
 
 import com.example.updateapp.R;
 
 public class OnboardingAdapter extends PagerAdapter {
 
-    Context context;
-    LayoutInflater layoutInflater;
+    private final Context context;
 
-    public OnboardingAdapter(Context context) {
-        this.context = context;
-    }
-
-    String titles[] = {
-          "Welcome to FinTrack",
-          "Track • Analyze • Improve",
-          "Build Better Money Habits"
+    private final int[] titles = {
+            R.string.onboarding_title_1,
+            R.string.onboarding_title_2,
+            R.string.onboarding_title_3
     };
 
-    String subtitles[] ={
-          "Your all-in-one AI companion for smarter spending,\nbetter savings, and complete financial clarity." ,
-          "Understand your expenses with clean visuals, smart insights, and real-time spending patterns\nthat keep you in control.",
-          "Set budgets, stay organized, and make confident \nfinancial decisions with powerful AI-Chatbot tools."
+    private final int[] subtitles = {
+            R.string.onboarding_subtitle_1,
+            R.string.onboarding_subtitle_2,
+            R.string.onboarding_subtitle_3
     };
 
-    int images[] = {
+    private final int[] images = {
             R.drawable.bg_1,
             R.drawable.bg_2,
             R.drawable.bg_3
     };
 
+    public OnboardingAdapter(Context context) {
+        this.context = context;
+    }
+
     @Override
     public int getCount() {
         return titles.length;
     }
 
     @Override
     public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
-        return view == (ConstraintLayout) object;
+        return view == object;
     }
 
     @NonNull
     @Override
     public Object instantiateItem(@NonNull ViewGroup container, int position) {
-        layoutInflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
-        View v = layoutInflater.inflate(R.layout.slide, container, false);
+        View v = LayoutInflater.from(context).inflate(R.layout.slide, container, false);
 
         ImageView image = v.findViewById(R.id.slideImg);
         TextView title = v.findViewById(R.id.sliderTitle);
         TextView subtitle = v.findViewById(R.id.sliderSubTitle);
 
         image.setImageResource(images[position]);
-        title.setText(titles[position]);
-        subtitle.setText(subtitles[position]);
+        title.setText(context.getString(titles[position]));
+        subtitle.setText(context.getString(subtitles[position]));
 
         container.addView(v);
-
         return v;
-
     }
 
     @Override
     public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
-        container.removeView((ConstraintLayout) object);
+        container.removeView((View) object);
     }
 }

app/src/main/java/com/example/updateapp/models/LanguageModel.java

@@ -44,4 +44,4 @@ public boolean isSelected() {
     public void setSelected(boolean selected) {
         isSelected = selected;
     }
-}
+}

app/src/main/java/com/example/updateapp/utils/LocaleHelper.java

@@ -4,7 +4,9 @@
 import android.content.SharedPreferences;
 import android.content.res.Configuration;
 import android.content.res.Resources;
-import android.os.Build;
+
+import androidx.appcompat.app.AppCompatDelegate;
+import androidx.core.os.LocaleListCompat;
 
 import java.util.Locale;
 
@@ -14,29 +16,44 @@ public class LocaleHelper {
     private static final String PREFS_NAME = "app_prefs";
 
     public static Context onAttach(Context context) {
-        String lang = getPersistedData(context, "en");
-        String country = getPersistedCountry(context, "");
-        return setLocale(context, lang, country);
+        return onAttach(context, "en");
     }
 
     public static Context onAttach(Context context, String defaultLanguage) {
         String lang = getPersistedData(context, defaultLanguage);
         String country = getPersistedCountry(context, "");
-        return setLocale(context, lang, country);
+        return wrap(context, lang, country);
     }
 
     public static String getLanguage(Context context) {
         return getPersistedData(context, "en");
     }
 
-    public static Context setLocale(Context context, String language, String country) {
-        persist(context, language, country);
+    public static String getCountry(Context context) {
+        return getPersistedCountry(context, "");
+    }
+
+    public static void applyPersistedLocales(Context context) {
+        applyAppLocales(getLanguage(context), getCountry(context));
+    }
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
-            return updateResources(context, language, country);
+    public static Context setLocale(Context context, String language, String country) {
+        if (language == null || language.isEmpty()) {
+            language = "en";
         }
+        if (country == null || "en".equals(language)) {
+            country = "";
+        }
+        persist(context, language, country);
+        applyAppLocales(language, country);
+        return wrap(context, language, country);
+    }
 
-        return updateResourcesLegacy(context, language, country);
+    private static void applyAppLocales(String language, String country) {
+        String tag = (country == null || country.isEmpty())
+                ? language
+                : language + "-" + country;
+        AppCompatDelegate.setApplicationLocales(LocaleListCompat.forLanguageTags(tag));
     }
 
     private static String getPersistedData(Context context, String defaultLanguage) {
@@ -53,11 +70,11 @@ private static void persist(Context context, String language, String country) {
         SharedPreferences preferences = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
         SharedPreferences.Editor editor = preferences.edit();
         editor.putString(SELECTED_LANGUAGE, language);
-        editor.putString(SELECTED_COUNTRY, country);
+        editor.putString(SELECTED_COUNTRY, country == null ? "" : country);
         editor.apply();
     }
 
-    private static Context updateResources(Context context, String language, String country) {
+    private static Context wrap(Context context, String language, String country) {
         Locale locale;
         if (country != null && !country.isEmpty()) {
             locale = new Locale(language, country);
@@ -66,38 +83,10 @@ private static Context updateResources(Context context, String language, String
         }
         Locale.setDefault(locale);
 
-        Configuration configuration = context.getResources().getConfiguration();
+        Resources resources = context.getResources();
+        Configuration configuration = new Configuration(resources.getConfiguration());
         configuration.setLocale(locale);
         configuration.setLayoutDirection(locale);
-
         return context.createConfigurationContext(configuration);
     }
-
-    private static Context updateResourcesLegacy(Context context, String language, String country) {
-        Locale locale;
-        if (country != null && !country.isEmpty()) {
-            locale = new Locale(language, country);
-        } else {
-            locale = new Locale(language);
-        }
-        Locale.setDefault(locale);
-
-        Resources resources = context.getResources();
-        Configuration configuration = resources.getConfiguration();
-        configuration.locale = locale;
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
-            configuration.setLayoutDirection(locale);
-        }
-
-        resources.updateConfiguration(configuration, resources.getDisplayMetrics());
-        return context;
-    }
-
-    public static void clearLanguagePreference(Context context) {
-        SharedPreferences preferences = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
-        SharedPreferences.Editor editor = preferences.edit();
-        editor.remove(SELECTED_LANGUAGE);
-        editor.remove(SELECTED_COUNTRY);
-        editor.apply();
-    }
-}
+}

app/src/main/java/com/example/updateapp/views/activites/LanguageActivity.java

@@ -66,7 +66,7 @@ private void setupLanguageList() {
         languageList = new ArrayList<>();
 
         // Add all 10 supported languages
-        languageList.add(new LanguageModel(getString(R.string.lang_english), "en", "US"));
+        languageList.add(new LanguageModel(getString(R.string.lang_english), "en", ""));
         languageList.add(new LanguageModel(getString(R.string.lang_chinese), "zh", "CN"));
         languageList.add(new LanguageModel(getString(R.string.lang_hindi), "hi", "IN"));
         languageList.add(new LanguageModel(getString(R.string.lang_spanish), "es", "ES"));
@@ -77,18 +77,17 @@ private void setupLanguageList() {
         languageList.add(new LanguageModel(getString(R.string.lang_russian), "ru", "RU"));
         languageList.add(new LanguageModel(getString(R.string.lang_urdu), "ur", "PK"));
 
-        // Set current language as selected
         String currentLanguage = LocaleHelper.getLanguage(this);
+        boolean found = false;
         for (int i = 0; i < languageList.size(); i++) {
             if (languageList.get(i).getLanguageCode().equals(currentLanguage)) {
                 languageList.get(i).setSelected(true);
                 selectedPosition = i;
+                found = true;
                 break;
             }
         }
-
-        // If no match found, default to English (position 0)
-        if (selectedPosition == 0 && !currentLanguage.equals("en")) {
+        if (!found) {
             languageList.get(0).setSelected(true);
             selectedPosition = 0;
         }

app/src/main/java/com/example/updateapp/views/activites/LoginActivity.java

@@ -222,7 +222,7 @@ public void onComplete(@NonNull Task<AuthResult> task) {
                         this,
                         getString(R.string.google_signin_error, e.getStatusCode(), e.getMessage()),
                         Toast.LENGTH_LONG
-                ).show();
+                )                .show();
             }
         }
     }

app/src/main/java/com/example/updateapp/views/activites/OTPActivity.java

@@ -183,15 +183,15 @@ private void verifyCredential(PhoneAuthCredential credential) {
                                     dialog.dismiss();
 
                                     Exception e = linkTask.getException();
-                                    String msg = e != null ? e.getMessage() : "Unknown linking error";
+                                    String msg = e != null ? e.getMessage() : getString(R.string.unknown_linking_error);
 
                                     if (e instanceof FirebaseAuthUserCollisionException) {
                                         Toast.makeText(OTPActivity.this,
-                                                "This email is already registered with a different account. Please login with that email or use another email.",
+                                                getString(R.string.email_already_registered_different),
                                                 Toast.LENGTH_LONG).show();
                                     } else {
                                         Toast.makeText(OTPActivity.this,
-                                                "Failed to link email: " + msg,
+                                                getString(R.string.failed_to_link_email, msg),
                                                 Toast.LENGTH_LONG).show();
                                     }
                                 }
@@ -224,7 +224,7 @@ private void saveUserToFirestoreAndContinue(String uid, String name, String emai
                 })
                 .addOnFailureListener(e -> {
                     if (dialog.isShowing()) dialog.dismiss();
-                    Toast.makeText(OTPActivity.this, "Failed to save user data: " + e.getMessage(), Toast.LENGTH_LONG).show();
+                    Toast.makeText(OTPActivity.this, getString(R.string.failed_to_save_user, e.getMessage()), Toast.LENGTH_LONG).show();
                 });
     }