adding a toggle for forcing English language

app/src/main/kotlin/com/simplemobiletools/filemanager/App.kt

@@ -2,10 +2,18 @@ package com.simplemobiletools.filemanager
 
 import android.app.Application
 import com.github.ajalt.reprint.core.Reprint
+import com.simplemobiletools.filemanager.extensions.config
+import java.util.*
 
 class App : Application() {
     override fun onCreate() {
         super.onCreate()
+
+        if (config.useEnglish) {
+            val conf = resources.configuration
+            conf.locale = Locale.ENGLISH
+            resources.updateConfiguration(conf, resources.displayMetrics)
+        }
         Reprint.initialize(this)
     }
 }

app/src/main/kotlin/com/simplemobiletools/filemanager/activities/MainActivity.kt

@@ -28,6 +28,8 @@ class MainActivity : SimpleActivity() {
     private val BACK_PRESS_TIMEOUT = 5000
     private var wasBackJustPressed = false
 
+    private var mStoredUseEnglish = false
+
     private lateinit var fragment: ItemsFragment
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -44,13 +46,24 @@ class MainActivity : SimpleActivity() {
         tryInitFileManager()
         checkWhatsNewDialog()
         checkIfRootAvailable()
+        storeStateVariables()
     }
 
     override fun onResume() {
         super.onResume()
+        if (mStoredUseEnglish != config.useEnglish) {
+            restartActivity()
+            return
+        }
+
         invalidateOptionsMenu()
     }
 
+    override fun onPause() {
+        super.onPause()
+        storeStateVariables()
+    }
+
     override fun onDestroy() {
         super.onDestroy()
         config.temporarilyShowHidden = false
@@ -72,6 +85,10 @@ class MainActivity : SimpleActivity() {
         return true
     }
 
+    private fun storeStateVariables() {
+        mStoredUseEnglish = config.useEnglish
+    }
+
     private fun tryInitFileManager() {
         handlePermission(PERMISSION_WRITE_STORAGE) {
             if (it) {

app/src/main/kotlin/com/simplemobiletools/filemanager/activities/SettingsActivity.kt

@@ -7,12 +7,14 @@ import com.simplemobiletools.commons.dialogs.SecurityDialog
 import com.simplemobiletools.commons.extensions.beVisibleIf
 import com.simplemobiletools.commons.extensions.handleHiddenFolderPasswordProtection
 import com.simplemobiletools.commons.extensions.updateTextColors
+import com.simplemobiletools.commons.extensions.useEnglishToggled
 import com.simplemobiletools.commons.helpers.PROTECTION_FINGERPRINT
 import com.simplemobiletools.commons.helpers.SHOW_ALL_TABS
 import com.simplemobiletools.filemanager.R
 import com.simplemobiletools.filemanager.extensions.config
 import com.simplemobiletools.filemanager.helpers.RootHelpers
 import kotlinx.android.synthetic.main.activity_settings.*
+import java.util.*
 
 class SettingsActivity : SimpleActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -24,6 +26,7 @@ class SettingsActivity : SimpleActivity() {
         super.onResume()
 
         setupCustomizeColors()
+        setupUseEnglish()
         setupManageFavorites()
         setupShowHidden()
         setupPasswordProtection()
@@ -44,6 +47,16 @@ class SettingsActivity : SimpleActivity() {
         }
     }
 
+    private fun setupUseEnglish() {
+        settings_use_english_holder.beVisibleIf(Locale.getDefault().language != "en")
+        settings_use_english.isChecked = config.useEnglish
+        settings_use_english_holder.setOnClickListener {
+            settings_use_english.toggle()
+            config.useEnglish = settings_use_english.isChecked
+            useEnglishToggled()
+        }
+    }
+
     private fun setupShowHidden() {
         settings_show_hidden.isChecked = config.showHidden
         settings_show_hidden_holder.setOnClickListener {

app/src/main/res/layout/activity_settings.xml

@@ -49,6 +49,26 @@
 
         </RelativeLayout>
 
+        <RelativeLayout
+            android:id="@+id/settings_use_english_holder"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/medium_margin"
+            android:background="?attr/selectableItemBackground"
+            android:padding="@dimen/activity_margin">
+
+            <com.simplemobiletools.commons.views.MySwitchCompat
+                android:id="@+id/settings_use_english"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:background="@null"
+                android:clickable="false"
+                android:paddingLeft="@dimen/medium_margin"
+                android:paddingStart="@dimen/medium_margin"
+                android:text="@string/use_english_language"/>
+
+        </RelativeLayout>
+
         <RelativeLayout
             android:id="@+id/settings_show_hidden_holder"
             android:layout_width="match_parent"