Merge pull request #2921 from B0pol/dev

Add language selector to change the app language

app/build.gradle

@@ -94,7 +94,7 @@ dependencies {
     implementation 'io.reactivex.rxjava2:rxjava:2.2.2'
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.0'
     implementation 'com.jakewharton.rxbinding2:rxbinding:2.1.1'
-    implementation 'org.ocpsoft.prettytime:prettytime:4.0.1.Final'
+    implementation 'org.ocpsoft.prettytime:prettytime:4.0.3.Final'
 
     implementation "androidx.room:room-runtime:${roomDbLibVersion}"
     implementation "androidx.room:room-rxjava2:${roomDbLibVersion}"

app/src/main/java/org/schabi/newpipe/App.java

@@ -99,7 +99,7 @@ public class App extends Application {
         NewPipe.init(getDownloader(),
                 Localization.getPreferredLocalization(this),
                 Localization.getPreferredContentCountry(this));
-        Localization.init();
+        Localization.init(getApplicationContext());
 
         StateSaver.init(this);
         initNotificationChannel();

app/src/main/java/org/schabi/newpipe/MainActivity.java

@@ -31,7 +31,6 @@ import android.preference.PreferenceManager;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.Menu;
-import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.Window;
@@ -56,7 +55,6 @@ import androidx.fragment.app.FragmentManager;
 import com.google.android.material.navigation.NavigationView;
 
 import org.schabi.newpipe.extractor.NewPipe;
-import org.schabi.newpipe.extractor.ServiceList;
 import org.schabi.newpipe.extractor.StreamingService;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.services.peertube.PeertubeInstance;
@@ -67,6 +65,7 @@ import org.schabi.newpipe.fragments.list.search.SearchFragment;
 import org.schabi.newpipe.report.ErrorActivity;
 import org.schabi.newpipe.util.Constants;
 import org.schabi.newpipe.util.KioskTranslator;
+import org.schabi.newpipe.util.Localization;
 import org.schabi.newpipe.util.NavigationHelper;
 import org.schabi.newpipe.util.PeertubeHelper;
 import org.schabi.newpipe.util.PermissionHelper;
@@ -78,6 +77,8 @@ import org.schabi.newpipe.util.ThemeHelper;
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class MainActivity extends AppCompatActivity {
     private static final String TAG = "MainActivity";
     public static final boolean DEBUG = !BuildConfig.BUILD_TYPE.equals("release");
@@ -113,9 +114,9 @@ public class MainActivity extends AppCompatActivity {
         if (Build.VERSION.SDK_INT == Build.VERSION_CODES.KITKAT) {
             TLSSocketFactoryCompat.setAsDefault();
         }
-
         ThemeHelper.setTheme(this, ServiceHelper.getSelectedServiceId(this));
 
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
@@ -419,6 +420,8 @@ public class MainActivity extends AppCompatActivity {
 
     @Override
     protected void onResume() {
+        assureCorrectAppLanguage(this);
+        Localization.init(getApplicationContext()); //change the date format to match the selected language on resume
         super.onResume();
 
         // close drawer on return, and don't show animation, so its looks like the drawer isn't open

app/src/main/java/org/schabi/newpipe/about/AboutActivity.java

@@ -22,9 +22,10 @@ import android.widget.TextView;
 
 import org.schabi.newpipe.BuildConfig;
 import org.schabi.newpipe.R;
-import org.schabi.newpipe.util.NavigationHelper;
 import org.schabi.newpipe.util.ThemeHelper;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class AboutActivity extends AppCompatActivity {
 
     /**
@@ -62,8 +63,10 @@ public class AboutActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceState);
         ThemeHelper.setTheme(this);
+        this.setTitle(getString(R.string.title_activity_about));
 
         setContentView(R.layout.activity_about);
 

app/src/main/java/org/schabi/newpipe/about/LicenseFragmentHelper.java

@@ -3,6 +3,7 @@ package org.schabi.newpipe.about;
 import android.app.Activity;
 import android.content.Context;
 import android.content.DialogInterface;
+import android.content.res.Resources;
 import android.os.AsyncTask;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
@@ -14,6 +15,8 @@ import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.lang.ref.WeakReference;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class LicenseFragmentHelper extends AsyncTask<Object, Void, Integer> {
 
     final WeakReference<Activity> weakReference;
@@ -55,15 +58,15 @@ public class LicenseFragmentHelper extends AsyncTask<Object, Void, Integer> {
         wv.loadData(webViewData, "text/html; charset=UTF-8", null);
 
         alert.setView(wv);
-        alert.setNegativeButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+        assureCorrectAppLanguage(activity.getApplicationContext());
-            @Override
+        alert.setNegativeButton(getFinishString(activity), (dialog, which) -> dialog.dismiss());
-            public void onClick(DialogInterface dialog, int which) {
-                dialog.dismiss();
-            }
-        });
         alert.show();
     }
 
+    private static String getFinishString(Activity activity) {
+        return activity.getApplicationContext().getResources().getString(R.string.finish);
+    }
+
     /**
      * @param context the context to use
      * @param license the license

app/src/main/java/org/schabi/newpipe/download/DownloadActivity.java

@@ -12,12 +12,13 @@ import android.view.MenuItem;
 import android.view.ViewTreeObserver;
 
 import org.schabi.newpipe.R;
-import org.schabi.newpipe.settings.SettingsActivity;
 import org.schabi.newpipe.util.ThemeHelper;
 
 import us.shandian.giga.service.DownloadManagerService;
 import us.shandian.giga.ui.fragment.MissionsFragment;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class DownloadActivity extends AppCompatActivity {
 
     private static final String MISSIONS_FRAGMENT_TAG = "fragment_tag";
@@ -29,6 +30,7 @@ public class DownloadActivity extends AppCompatActivity {
         i.setClass(this, DownloadManagerService.class);
         startService(i);
 
+        assureCorrectAppLanguage(this);
         ThemeHelper.setTheme(this);
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_downloader);

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -11,15 +11,6 @@ import android.os.Bundle;
 import android.os.Environment;
 import android.os.IBinder;
 import android.preference.PreferenceManager;
-import androidx.annotation.IdRes;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.annotation.StringRes;
-import androidx.fragment.app.DialogFragment;
-import androidx.documentfile.provider.DocumentFile;
-import androidx.appcompat.app.AlertDialog;
-import androidx.appcompat.view.menu.ActionMenuItemView;
-import androidx.appcompat.widget.Toolbar;
 import android.util.Log;
 import android.util.SparseArray;
 import android.view.LayoutInflater;
@@ -34,6 +25,16 @@ import android.widget.Spinner;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import androidx.annotation.IdRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.StringRes;
+import androidx.appcompat.app.AlertDialog;
+import androidx.appcompat.view.menu.ActionMenuItemView;
+import androidx.appcompat.widget.Toolbar;
+import androidx.documentfile.provider.DocumentFile;
+import androidx.fragment.app.DialogFragment;
+
 import com.nononsenseapps.filepicker.Utils;
 
 import org.schabi.newpipe.MainActivity;
@@ -78,6 +79,8 @@ import us.shandian.giga.service.DownloadManagerService;
 import us.shandian.giga.service.DownloadManagerService.DownloadManagerBinder;
 import us.shandian.giga.service.MissionState;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class DownloadDialog extends DialogFragment implements RadioGroup.OnCheckedChangeListener, AdapterView.OnItemSelectedListener {
     private static final String TAG = "DialogFragment";
     private static final boolean DEBUG = MainActivity.DEBUG;
@@ -527,10 +530,11 @@ public class DownloadDialog extends DialogFragment implements RadioGroup.OnCheck
     }
 
     private void showFailedDialog(@StringRes int msg) {
+        assureCorrectAppLanguage(getContext());
         new AlertDialog.Builder(context)
                 .setTitle(R.string.general_error)
                 .setMessage(msg)
-                .setNegativeButton(android.R.string.ok, null)
+                .setNegativeButton(getString(R.string.finish), null)
                 .create()
                 .show();
     }

app/src/main/java/org/schabi/newpipe/local/subscription/ImportConfirmationDialog.java

@@ -15,6 +15,8 @@ import org.schabi.newpipe.util.ThemeHelper;
 import icepick.Icepick;
 import icepick.State;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class ImportConfirmationDialog extends DialogFragment {
     @State
     protected Intent resultServiceIntent;
@@ -34,11 +36,12 @@ public class ImportConfirmationDialog extends DialogFragment {
     @NonNull
     @Override
     public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+        assureCorrectAppLanguage(getContext());
         return new AlertDialog.Builder(getContext(), ThemeHelper.getDialogTheme(getContext()))
                 .setMessage(R.string.import_network_expensive_warning)
                 .setCancelable(true)
                 .setNegativeButton(R.string.cancel, null)
-                .setPositiveButton(android.R.string.ok, (dialogInterface, i) -> {
+                .setPositiveButton(R.string.finish, (dialogInterface, i) -> {
                     if (resultServiceIntent != null && getContext() != null) {
                         getContext().startService(resultServiceIntent);
                     }

app/src/main/java/org/schabi/newpipe/player/BackgroundPlayer.java

@@ -58,7 +58,7 @@ import org.schabi.newpipe.util.NavigationHelper;
 import org.schabi.newpipe.util.ThemeHelper;
 
 import static org.schabi.newpipe.player.helper.PlayerHelper.getTimeString;
-
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 /**
  * Base players joining the common properties
@@ -115,7 +115,7 @@ public final class BackgroundPlayer extends Service {
         notificationManager = ((NotificationManager) getSystemService(NOTIFICATION_SERVICE));
         lockManager = new LockManager(this);
         sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
-
+        assureCorrectAppLanguage(this);
         ThemeHelper.setTheme(this);
         basePlayerImpl = new BasePlayerImpl(this);
         basePlayerImpl.setup();

app/src/main/java/org/schabi/newpipe/player/MainVideoPlayer.java

@@ -95,6 +95,7 @@ import static org.schabi.newpipe.util.AnimationUtils.Type.SCALE_AND_ALPHA;
 import static org.schabi.newpipe.util.AnimationUtils.Type.SLIDE_AND_ALPHA;
 import static org.schabi.newpipe.util.AnimationUtils.animateRotation;
 import static org.schabi.newpipe.util.AnimationUtils.animateView;
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 import static org.schabi.newpipe.util.StateSaver.KEY_SAVED_STATE;
 
 /**
@@ -125,6 +126,7 @@ public final class MainVideoPlayer extends AppCompatActivity
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceState);
         if (DEBUG) Log.d(TAG, "onCreate() called with: savedInstanceState = [" + savedInstanceState + "]");
         defaultPreferences = PreferenceManager.getDefaultSharedPreferences(this);
@@ -192,6 +194,7 @@ public final class MainVideoPlayer extends AppCompatActivity
     @Override
     protected void onResume() {
         if (DEBUG) Log.d(TAG, "onResume() called");
+        assureCorrectAppLanguage(this);
         super.onResume();
 
         if (globalScreenOrientationLocked()) {
@@ -222,6 +225,7 @@ public final class MainVideoPlayer extends AppCompatActivity
     @Override
     public void onConfigurationChanged(Configuration newConfig) {
         super.onConfigurationChanged(newConfig);
+        assureCorrectAppLanguage(this);
 
         if (playerImpl.isSomePopupMenuVisible()) {
             playerImpl.getQualityPopupMenu().dismiss();
@@ -366,8 +370,8 @@ public final class MainVideoPlayer extends AppCompatActivity
     }
 
     private boolean globalScreenOrientationLocked() {
-        // 1: Screen orientation changes using acelerometer
+        // 1: Screen orientation changes using accelerometer
-        // 0: Screen orientatino is locked
+        // 0: Screen orientation is locked
         return !(android.provider.Settings.System.getInt(getContentResolver(), Settings.System.ACCELEROMETER_ROTATION, 0) == 1);
     }
 

app/src/main/java/org/schabi/newpipe/player/PopupVideoPlayer.java

@@ -80,6 +80,7 @@ import static org.schabi.newpipe.player.BasePlayer.STATE_PLAYING;
 import static org.schabi.newpipe.player.VideoPlayer.DEFAULT_CONTROLS_DURATION;
 import static org.schabi.newpipe.player.VideoPlayer.DEFAULT_CONTROLS_HIDE_TIME;
 import static org.schabi.newpipe.util.AnimationUtils.animateView;
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 /**
  * Service Popup Player implementing VideoPlayer
@@ -142,6 +143,7 @@ public final class PopupVideoPlayer extends Service {
 
     @Override
     public void onCreate() {
+        assureCorrectAppLanguage(this);
         windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
         notificationManager = ((NotificationManager) getSystemService(NOTIFICATION_SERVICE));
 
@@ -169,6 +171,7 @@ public final class PopupVideoPlayer extends Service {
 
     @Override
     public void onConfigurationChanged(Configuration newConfig) {
+        assureCorrectAppLanguage(this);
         if (DEBUG) Log.d(TAG, "onConfigurationChanged() called with: newConfig = [" + newConfig + "]");
         updateScreenSize();
         updatePopupSize(popupLayoutParams.width, -1);

app/src/main/java/org/schabi/newpipe/player/ServicePlayerActivity.java

@@ -46,6 +46,7 @@ import java.util.List;
 
 import static org.schabi.newpipe.player.helper.PlayerHelper.formatPitch;
 import static org.schabi.newpipe.player.helper.PlayerHelper.formatSpeed;
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 public abstract class ServicePlayerActivity extends AppCompatActivity
         implements PlayerEventListener, SeekBar.OnSeekBarChangeListener,
@@ -116,6 +117,7 @@ public abstract class ServicePlayerActivity extends AppCompatActivity
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceState);
         ThemeHelper.setTheme(this);
         setContentView(R.layout.activity_player_queue_control);

app/src/main/java/org/schabi/newpipe/player/helper/PlaybackParameterDialog.java

@@ -17,6 +17,7 @@ import org.schabi.newpipe.R;
 import org.schabi.newpipe.util.SliderStrategy;
 
 import static org.schabi.newpipe.player.BasePlayer.DEBUG;
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 public class PlaybackParameterDialog extends DialogFragment {
     @NonNull private static final String TAG = "PlaybackParameterDialog";
@@ -108,6 +109,7 @@ public class PlaybackParameterDialog extends DialogFragment {
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
+        assureCorrectAppLanguage(getContext());
         super.onCreate(savedInstanceState);
         if (savedInstanceState != null) {
             initialTempo = savedInstanceState.getDouble(INITIAL_TEMPO_KEY, DEFAULT_TEMPO);
@@ -137,6 +139,7 @@ public class PlaybackParameterDialog extends DialogFragment {
     @NonNull
     @Override
     public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+        assureCorrectAppLanguage(getContext());
         final View view = View.inflate(getContext(), R.layout.dialog_playback_parameter, null);
         setupControlViews(view);
 

app/src/main/java/org/schabi/newpipe/report/ErrorActivity.java

@@ -46,6 +46,8 @@ import java.util.List;
 import java.util.TimeZone;
 import java.util.Vector;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 /*
  * Created by Christian Schabesberger on 24.10.15.
  *
@@ -171,6 +173,7 @@ public class ErrorActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceState);
         ThemeHelper.setTheme(this);
         setContentView(R.layout.activity_error);

app/src/main/java/org/schabi/newpipe/settings/ContentSettingsFragment.java

@@ -7,11 +7,12 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
+import android.util.Log;
+import android.widget.Toast;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.preference.Preference;
-import android.util.Log;
-import android.widget.Toast;
 
 import com.nononsenseapps.filepicker.Utils;
 import com.nostra13.universalimageloader.core.ImageLoader;
@@ -40,6 +41,8 @@ import java.util.Map;
 import java.util.zip.ZipFile;
 import java.util.zip.ZipOutputStream;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class ContentSettingsFragment extends BasePreferenceFragment {
 
     private static final int REQUEST_IMPORT_PATH = 8945;
@@ -56,6 +59,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
 
     private Localization initialSelectedLocalization;
     private ContentCountry initialSelectedContentCountry;
+    private String initialLanguage;
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -64,6 +68,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
 
         initialSelectedLocalization = org.schabi.newpipe.util.Localization.getPreferredLocalization(requireContext());
         initialSelectedContentCountry = org.schabi.newpipe.util.Localization.getPreferredContentCountry(requireContext());
+        initialLanguage = PreferenceManager.getDefaultSharedPreferences(getContext()).getString("app_language_key", "en");
     }
 
     @Override
@@ -125,9 +130,10 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
                 .getPreferredLocalization(requireContext());
         final ContentCountry selectedContentCountry = org.schabi.newpipe.util.Localization
                 .getPreferredContentCountry(requireContext());
+        final String selectedLanguage = PreferenceManager.getDefaultSharedPreferences(getContext()).getString("app_language_key", "en");
 
         if (!selectedLocalization.equals(initialSelectedLocalization)
-                || !selectedContentCountry.equals(initialSelectedContentCountry)) {
+                || !selectedContentCountry.equals(initialSelectedContentCountry) || !selectedLanguage.equals(initialLanguage)) {
             Toast.makeText(requireContext(), R.string.localization_changes_requires_app_restart, Toast.LENGTH_LONG).show();
 
             NewPipe.setupLocalization(selectedLocalization, selectedContentCountry);
@@ -136,6 +142,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
 
     @Override
     public void onActivityResult(int requestCode, int resultCode, @NonNull Intent data) {
+        assureCorrectAppLanguage(getContext());
         super.onActivityResult(requestCode, resultCode, data);
         if (DEBUG) {
             Log.d(TAG, "onActivityResult() called with: requestCode = [" + requestCode + "], resultCode = [" + resultCode + "], data = [" + data + "]");
@@ -150,7 +157,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             } else {
                 AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                 builder.setMessage(R.string.override_current_data)
-                        .setPositiveButton(android.R.string.ok,
+                        .setPositiveButton(getString(R.string.finish),
                                 (DialogInterface d, int id) -> importDatabase(path))
                         .setNegativeButton(android.R.string.cancel,
                                 (DialogInterface d, int id) -> d.cancel());
@@ -189,7 +196,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
-        }finally {
+        } finally {
             try {
                 if (output != null) {
                     output.flush();
@@ -236,7 +243,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             }
 
             //If settings file exist, ask if it should be imported.
-            if(ZipHelper.extractFileFromZip(filePath, newpipe_settings.getPath(), "newpipe.settings")) {
+            if (ZipHelper.extractFileFromZip(filePath, newpipe_settings.getPath(), "newpipe.settings")) {
                 AlertDialog.Builder alert = new AlertDialog.Builder(getContext());
                 alert.setTitle(R.string.import_settings);
 
@@ -245,7 +252,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
                     // restart app to properly load db
                     System.exit(0);
                 });
-                alert.setPositiveButton(android.R.string.yes, (dialog, which) -> {
+                alert.setPositiveButton(getString(R.string.finish), (dialog, which) -> {
                     dialog.dismiss();
                     loadSharedPreferences(newpipe_settings);
                     // restart app to properly load db
@@ -291,7 +298,7 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
             e.printStackTrace();
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
-        }finally {
+        } finally {
             try {
                 if (input != null) {
                     input.close();

app/src/main/java/org/schabi/newpipe/settings/DownloadSettingsFragment.java

@@ -8,11 +8,12 @@ import android.content.Intent;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
+import android.util.Log;
+import android.widget.Toast;
+
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.preference.Preference;
-import android.util.Log;
-import android.widget.Toast;
 
 import com.nononsenseapps.filepicker.Utils;
 
@@ -28,6 +29,8 @@ import java.nio.charset.StandardCharsets;
 
 import us.shandian.giga.io.StoredDirectoryHelper;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
+
 public class DownloadSettingsFragment extends BasePreferenceFragment {
     private static final int REQUEST_DOWNLOAD_VIDEO_PATH = 0x1235;
     private static final int REQUEST_DOWNLOAD_AUDIO_PATH = 0x1236;
@@ -159,7 +162,7 @@ public class DownloadSettingsFragment extends BasePreferenceFragment {
         AlertDialog.Builder msg = new AlertDialog.Builder(ctx);
         msg.setTitle(title);
         msg.setMessage(message);
-        msg.setPositiveButton(android.R.string.ok, null);
+        msg.setPositiveButton(getString(R.string.finish), null);
         msg.show();
     }
 
@@ -202,6 +205,7 @@ public class DownloadSettingsFragment extends BasePreferenceFragment {
 
     @Override
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        assureCorrectAppLanguage(getContext());
         super.onActivityResult(requestCode, resultCode, data);
         if (DEBUG) {
             Log.d(TAG, "onActivityResult() called with: requestCode = [" + requestCode + "], " +

app/src/main/java/org/schabi/newpipe/settings/SettingsActivity.java

@@ -14,6 +14,7 @@ import android.view.MenuItem;
 import org.schabi.newpipe.R;
 import org.schabi.newpipe.util.ThemeHelper;
 
+import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
 /*
  * Created by Christian Schabesberger on 31.08.15.
@@ -44,7 +45,7 @@ public class SettingsActivity extends AppCompatActivity implements BasePreferenc
     @Override
     protected void onCreate(Bundle savedInstanceBundle) {
         setTheme(ThemeHelper.getSettingsThemeStyle(this));
-
+        assureCorrectAppLanguage(this);
         super.onCreate(savedInstanceBundle);
         setContentView(R.layout.settings_layout);
 

app/src/main/java/org/schabi/newpipe/util/Localization.java

@@ -1,9 +1,17 @@
 package org.schabi.newpipe.util;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
+import android.content.res.Resources;
 import android.preference.PreferenceManager;
 import android.text.TextUtils;
+import android.util.DisplayMetrics;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.PluralsRes;
+import androidx.annotation.StringRes;
 
 import org.ocpsoft.prettytime.PrettyTime;
 import org.ocpsoft.prettytime.units.Decade;
@@ -18,10 +26,6 @@ import java.util.Date;
 import java.util.List;
 import java.util.Locale;
 
-import androidx.annotation.NonNull;
-import androidx.annotation.PluralsRes;
-import androidx.annotation.StringRes;
-
 /*
  * Created by chschtsch on 12/29/15.
  *
@@ -50,8 +54,8 @@ public class Localization {
     private Localization() {
     }
 
-    public static void init() {
+    public static void init(Context context) {
-        initPrettyTime();
+        initPrettyTime(context);
     }
 
     @NonNull
@@ -115,12 +119,13 @@ public class Localization {
         return nf.format(number);
     }
 
-    public static String formatDate(Date date) {
+    public static String formatDate(Date date, Context context) {
-        return DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.getDefault()).format(date);
+        return DateFormat.getDateInstance(DateFormat.MEDIUM, getAppLocale(context)).format(date);
     }
 
+    @SuppressLint("StringFormatInvalid")
     public static String localizeUploadDate(Context context, Date date) {
-        return context.getString(R.string.upload_date_text, formatDate(date));
+        return context.getString(R.string.upload_date_text, formatDate(date, context));
     }
 
     public static String localizeViewCount(Context context, long viewCount) {
@@ -199,21 +204,47 @@ public class Localization {
     // Pretty Time
     //////////////////////////////////////////////////////////////////////////*/
 
-    private static void initPrettyTime() {
+    private static void initPrettyTime(Context context) {
-        prettyTime = new PrettyTime(Locale.getDefault());
+        prettyTime = new PrettyTime(getAppLocale(context));
         // Do not use decades as YouTube doesn't either.
         prettyTime.removeUnit(Decade.class);
     }
 
     private static PrettyTime getPrettyTime() {
-        // If pretty time's Locale is different, init again with the new one.
-        if (!prettyTime.getLocale().equals(Locale.getDefault())) {
-            initPrettyTime();
-        }
         return prettyTime;
     }
 
     public static String relativeTime(Calendar calendarTime) {
         return getPrettyTime().formatUnrounded(calendarTime);
     }
+
+    private static void changeAppLanguage(Locale loc, Resources res) {
+        DisplayMetrics dm = res.getDisplayMetrics();
+        Configuration conf = res.getConfiguration();
+        conf.setLocale(loc);
+        res.updateConfiguration(conf, dm);
+    }
+
+    public static Locale getAppLocale(Context context) {
+        SharedPreferences prefs = androidx.preference.PreferenceManager.getDefaultSharedPreferences(context);
+        String lang = prefs.getString("app_language_key", "en");
+        Locale loc;
+        if (lang.equals("system")) {
+            loc = Locale.getDefault();
+        } else if (lang.matches(".*-.*")) {
+            //to differentiate different versions of the language
+            //for example, pt (portuguese in Portugal) and pt-br (portuguese in Brazil)
+            String[] localisation = lang.split("-");
+            lang = localisation[0];
+            String country = localisation[1];
+            loc = new Locale(lang, country);
+        } else {
+            loc = new Locale(lang);
+        }
+        return loc;
+    }
+
+    public static void assureCorrectAppLanguage(Context c) {
+        changeAppLanguage(getAppLocale(c), c.getResources());
+    }
 }

app/src/main/java/us/shandian/giga/ui/adapter/MissionAdapter.java

@@ -534,7 +534,7 @@ public class MissionAdapter extends Adapter<ViewHolder> implements Handler.Callb
             );
         }
 
-        builder.setNegativeButton(android.R.string.ok, (dialog, which) -> dialog.cancel())
+        builder.setNegativeButton(R.string.finish, (dialog, which) -> dialog.cancel())
                 .setTitle(mission.storage.getName())
                 .create()
                 .show();

app/src/main/res/values/settings_keys.xml

@@ -31,20 +31,20 @@
     <string name="seek_duration_key" translatable="false">seek_duration</string>
     <string name="seek_duration_default_value" translatable="false">10000</string>
     <string-array name="seek_duration_description" translatable="false">
-      <item>5 seconds</item>
+        <item>5 seconds</item>
-      <item>10 seconds</item>
+        <item>10 seconds</item>
-      <item>15 seconds</item>
+        <item>15 seconds</item>
-      <item>20 seconds</item>
+        <item>20 seconds</item>
-      <item>25 seconds</item>
+        <item>25 seconds</item>
-      <item>30 seconds</item>
+        <item>30 seconds</item>
     </string-array>
     <string-array name="seek_duration_value" translatable="false">
-      <item>5000</item>
+        <item>5000</item>
-      <item>10000</item>
+        <item>10000</item>
-      <item>15000</item>
+        <item>15000</item>
-      <item>20000</item>
+        <item>20000</item>
-      <item>25000</item>
+        <item>25000</item>
-      <item>30000</item>
+        <item>30000</item>
     </string-array>
 
     <string name="minimize_on_exit_key" translatable="false">minimize_on_exit_key</string>
@@ -175,6 +175,8 @@
     <string name="main_page_content_key" translatable="false">main_page_content</string>
     <string name="enable_playback_resume_key" translatable="false">enable_playback_resume</string>
     <string name="enable_playback_state_lists_key" translatable="false">enable_playback_state_lists</string>
+
+    <string name="app_language_key" translatable="false">app_language_key</string>
     <string name="enable_lock_screen_video_thumbnail_key" translatable="false">enable_lock_screen_video_thumbnail</string>
 
     <string name="import_data" translatable="false">import_data</string>
@@ -924,6 +926,138 @@
         <item>ZW</item>
     </string-array>
 
+    <!--The next two arrays are set to change the app language-->
+    <string-array name="app_language_code" translatable="false">
+        <item>system</item>
+        <item>ar</item>
+        <item>az</item>
+        <item>ast</item>
+        <item>be</item>
+        <item>bg-bd</item>
+        <item>bn</item>
+        <item>ca</item>
+        <item>cs</item>
+        <item>da</item>
+        <item>de</item>
+        <item>el</item>
+        <item>en</item>
+        <item>eo</item>
+        <item>es</item>
+        <item>et</item>
+        <item>eu</item>
+        <item>fa</item>
+        <item>fi</item>
+        <item>fil</item>
+        <item>fr</item>
+        <item>gl</item>
+        <item>he</item>
+        <item>hi</item>
+        <item>hr</item>
+        <item>hu</item>
+        <item>hy</item>
+        <item>ia</item>
+        <item>in</item>
+        <item>it</item>
+        <item>ja</item>
+        <item>ko</item>
+        <item>ku</item>
+        <item>lt</item>
+        <item>mk</item>
+        <item>ms</item>
+        <item>nb-no</item>
+        <item>ne</item>
+        <item>nl</item>
+        <item>nl-be</item>
+        <item>oc</item>
+        <item>pa</item>
+        <item>pl</item>
+        <item>pr</item>
+        <item>pt</item>
+        <item>pt-br</item>
+        <item>ro</item>
+        <item>ru</item>
+        <item>sk</item>
+        <item>sl</item>
+        <item>sq</item>
+        <item>sr</item>
+        <item>sv</item>
+        <item>ta</item>
+        <item>te</item>
+        <item>th</item>
+        <item>tr</item>
+        <item>uk</item>
+        <item>ur</item>
+        <item>vi</item>
+        <item>zh</item>
+        <item>zh-hans</item>
+        <item>zh-tw</item>
+    </string-array>
+    <string-array name="app_language_name" translatable="false">
+        <item>@string/systems_language</item>
+        <item>العربية</item>
+        <item>Azərbaycan dili</item>
+        <item>Asturianu</item>
+        <item>Беларуская</item>
+        <item>български език</item>
+        <item>বাংলা</item>
+        <item>Català</item>
+        <item>Čeština</item>
+        <item>Dansk</item>
+        <item>Deutsch</item>
+        <item>Ελληνικά</item>
+        <item>English</item>
+        <item>Esperanto</item>
+        <item>Español</item>
+        <item>Eesti keel</item>
+        <item>Euskara</item>
+        <item>فارسی</item>
+        <item>Suomen kieli</item>
+        <item>Wikang Filipino</item>
+        <item>Français</item>
+        <item>Galego</item>
+        <item>עברית</item>
+        <item>हिन्दी</item>
+        <item>Hrvatski</item>
+        <item>magyar</item>
+        <item>Հայերեն</item>
+        <item>Interlingua</item>
+        <item>Bahasa Indonesia</item>
+        <item>Italiano</item>
+        <item>日本語</item>
+        <item>한국어</item>
+        <item>کوردی</item>
+        <item>Lietuvių kalba</item>
+        <item>македонски јазик</item>
+        <item>Bahasa Melayu</item>
+        <item>Norsk bokmål</item>
+        <item>Nनेपाली</item>
+        <item>Nederlands (NL)</item>
+        <item>Nederlands (BE)</item>
+        <item>Occitan</item>
+        <item>ਪੰਜਾਬੀ</item>
+        <item>Polski</item>
+        <item>Pirate Language</item>
+        <item>Português (PT)</item>
+        <item>Português (BR)</item>
+        <item>Română</item>
+        <item>русский язык</item>
+        <item>Slovenčina</item>
+        <item>Slovenščina</item>
+        <item>Shqip</item>
+        <item>Српски</item>
+        <item>Svenska</item>
+        <item>தமிழ்</item>
+        <item>తెలుగు</item>
+        <item>ไทย</item>
+        <item>Türkçe</item>
+        <item>українська мова</item>
+        <item>اردو</item>
+        <item>Tiếng Việt</item>
+        <item>官话</item>
+        <item>简化字</item>
+        <item>臺灣華語</item>
+    </string-array>
+
     <!-- Limit mobile data usage  -->
     <string name="limit_mobile_data_usage_key" translatable="false">limit_mobile_data_usage</string>
     <string name="limit_data_usage_none_key" translatable="false">limit_data_usage_none</string>

app/src/main/res/values/strings.xml

@@ -590,4 +590,6 @@
     <string name="downloads_storage_use_saf_title">Use SAF</string>
     <string name="downloads_storage_use_saf_summary">The Storage Access Framework allows downloads to an external SD card.\nNote: some devices are not compatible</string>
     <string name="choose_instance_prompt">Choose an instance</string>
+    <string name="app_language_title">App language</string>
+    <string name="systems_language">System default</string>
 </resources>

app/src/main/res/xml/content_settings.xml

@@ -3,6 +3,16 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:title="@string/content">
+
+    <ListPreference
+        app:iconSpaceReserved="false"
+        android:defaultValue="system"
+        android:entries="@array/app_language_name"
+        android:entryValues="@array/app_language_code"
+        android:key="@string/app_language_key"
+        android:summary="%s"
+        android:title="@string/app_language_title"/>
+
     <ListPreference
         app:iconSpaceReserved="false"
         android:defaultValue="@string/default_language_value"