Add in-app language switcher

Closes #53

app/src/main/java/org/shadowice/flocke/andotp/Activities/MainActivity.java

@@ -366,7 +366,8 @@ public class MainActivity extends BaseActivity
                 key.equals(getString(R.string.settings_key_tap_to_reveal)) ||
                 key.equals(getString(R.string.settings_key_label_scroll))) {
             adapter.notifyDataSetChanged();
-        } else if (key.equals(getString(R.string.settings_key_theme))) {
+        } else if (key.equals(getString(R.string.settings_key_theme)) ||
+                key.equals(getString(R.string.settings_key_lang))) {
             recreate();
         }
     }

app/src/main/java/org/shadowice/flocke/andotp/Activities/SettingsActivity.java

@@ -85,7 +85,8 @@ public class SettingsActivity extends BaseActivity
     }
 
     public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
-        if (key.equals(getString(R.string.settings_key_theme))) {
+        if (key.equals(getString(R.string.settings_key_theme)) ||
+                key.equals(getString(R.string.settings_key_lang))) {
             recreate();
         }
     }

app/src/main/java/org/shadowice/flocke/andotp/Activities/ThemedActivity.java

@@ -22,12 +22,15 @@
 
 package org.shadowice.flocke.andotp.Activities;
 
+import android.content.res.Configuration;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 
 import org.shadowice.flocke.andotp.R;
 import org.shadowice.flocke.andotp.Utilities.Settings;
 
+import java.util.Locale;
+
 public abstract class ThemedActivity extends AppCompatActivity {
     public Settings settings;
 
@@ -35,6 +38,20 @@ public abstract class ThemedActivity extends AppCompatActivity {
     protected void onCreate(Bundle savedInstanceState) {
         settings = new Settings(this);
 
+        setTheme();
+        setLocale();
+
+        super.onCreate(savedInstanceState);
+    }
+
+    @Override
+    public void onResume() {
+        setLocale();
+
+        super.onResume();
+    }
+
+    public void setTheme() {
         String theme = settings.getTheme();
 
         if (theme.equals("light")) {
@@ -44,7 +61,15 @@ public abstract class ThemedActivity extends AppCompatActivity {
         } else if (theme.equals("black")) {
             setTheme(R.style.AppTheme_Black_NoActionBar);
         }
+    }
 
-        super.onCreate(savedInstanceState);
+    public void setLocale() {
+        Locale locale = settings.getLang();
+        Locale.setDefault(locale);
+
+        Configuration config = new Configuration();
+        config.locale = locale;
+
+        getBaseContext().getResources().updateConfiguration(config, getBaseContext().getResources().getDisplayMetrics());
     }
 }

app/src/main/java/org/shadowice/flocke/andotp/Utilities/Settings.java

@@ -36,6 +36,7 @@ import java.io.File;
 import java.nio.charset.StandardCharsets;
 import java.security.KeyPair;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Set;
 
 import static org.shadowice.flocke.andotp.Preferences.PasswordEncryptedPreference.KEY_ALIAS;
@@ -202,6 +203,15 @@ public class Settings {
         return settings.getStringSet(getResString(R.string.settings_key_panic), Collections.<String>emptySet());
     }
 
+    public Locale getLang() {
+        String lang = getString(R.string.settings_key_lang, R.string.settings_default_lang);
+
+        if (lang.equals("system"))
+            return Tools.getSystemLocale();
+        else
+            return new Locale(lang);
+    }
+
     public String getTheme() {
         return getString(R.string.settings_key_theme, R.string.settings_default_theme);
     }

app/src/main/java/org/shadowice/flocke/andotp/Utilities/Tools.java

@@ -29,9 +29,11 @@ import android.graphics.ColorFilter;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Environment;
 
 import java.io.File;
+import java.util.Locale;
 
 public class Tools {
     /* Checks if external storage is available for read and write */
@@ -70,4 +72,12 @@ public class Tools {
         File dir = new File(path);
         return dir.exists() || dir.mkdirs();
     }
+
+    public static Locale getSystemLocale() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            return Resources.getSystem().getConfiguration().getLocales().get(0);
+        } else {
+            return Resources.getSystem().getConfiguration().locale;
+        }
+    }
 }

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

@@ -11,6 +11,7 @@
     <string name="settings_key_auth_pin_hash" translatable="false">pref_auth_pin_hash</string>
     <string name="settings_key_panic" translatable="false">pref_panic</string>
 
+    <string name="settings_key_lang" translatable="false">pref_lang</string>
     <string name="settings_key_theme" translatable="false">pref_theme</string>
     <string name="settings_key_label_size" translatable="false">pref_label_size</string>
     <string name="settings_key_label_scroll" translatable="false">pref_label_scroll</string>
@@ -30,6 +31,7 @@
 
     <!-- Default values -->
     <string name="settings_default_auth" translatable="false">none</string>
+    <string name="settings_default_lang" translatable="false">system</string>
     <string name="settings_default_theme" translatable="false">light</string>
     <integer name="settings_default_label_size">8</integer>
 
@@ -46,6 +48,19 @@
         <item>settings</item>
     </string-array>
 
+    <string-array name="settings_values_lang" translatable="false">
+        <item>system</item>
+        <item>en</item>
+        <item>cs</item>
+        <item>de</item>
+        <item>es</item>
+        <item>fr</item>
+        <item>gl</item>
+        <item>nl</item>
+        <item>pl</item>
+        <item>ru</item>
+    </string-array>
+
     <string-array name="settings_values_theme" translatable="false">
         <item>light</item>
         <item>dark</item>

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

@@ -14,6 +14,7 @@
     <string name="settings_title_auth_pin">PIN</string>
     <string name="settings_title_panic">Panic Trigger</string>
 
+    <string name="settings_title_lang">Language</string>
     <string name="settings_title_theme">Theme</string>
     <string name="settings_title_label_size">Label font size</string>
     <string name="settings_title_label_scroll">Scroll label</string>
@@ -64,6 +65,19 @@
         <item>Reset app settings</item>
     </string-array>
 
+    <string-array name="settings_entries_lang">
+        <item>System default</item>
+        <item>English</item>
+        <item>Czech</item>
+        <item>German</item>
+        <item>Spanish</item>
+        <item>French</item>
+        <item>Galician</item>
+        <item>Dutch</item>
+        <item>Polish</item>
+        <item>Russian</item>
+    </string-array>
+
     <string-array name="settings_entries_theme">
         <item>Light theme</item>
         <item>Dark theme</item>

app/src/main/res/xml/preferences.xml

@@ -37,6 +37,14 @@
     <PreferenceCategory
         android:title="@string/settings_category_title_ui">
 
+        <ListPreference
+            android:key="@string/settings_key_lang"
+            android:title="@string/settings_title_lang"
+            android:summary="%s"
+            android:entries="@array/settings_entries_lang"
+            android:entryValues="@array/settings_values_lang"
+            android:defaultValue="@string/settings_default_lang" />
+
         <ListPreference
             android:key="@string/settings_key_theme"
             android:title="@string/settings_title_theme"