Implement language switcher (#563)

* Implement language switching using BaseActivity

* Add requested changes

* Cleanup App.kt Imports and add pref_language_key

* Acutally use @string for key

* Use string resource for language preference title

app/src/main/java/eu/kanade/tachiyomi/App.kt

@@ -2,10 +2,12 @@ package eu.kanade.tachiyomi
 
 import android.app.Application
 import android.content.Context
+import android.content.res.Configuration
 import android.support.multidex.MultiDex
 import com.evernote.android.job.JobManager
 import eu.kanade.tachiyomi.data.library.LibraryUpdateJob
 import eu.kanade.tachiyomi.data.updater.UpdateCheckerJob
+import eu.kanade.tachiyomi.util.LocaleHelper
 import org.acra.ACRA
 import org.acra.annotation.ReportsCrashes
 import timber.log.Timber
@@ -31,6 +33,8 @@ open class App : Application() {
 
         setupAcra()
         setupJobManager()
+
+        LocaleHelper.updateCfg(this, baseContext.resources.configuration)
     }
 
     override fun attachBaseContext(base: Context) {
@@ -40,6 +44,11 @@ open class App : Application() {
         }
     }
 
+    override fun onConfigurationChanged(newConfig: Configuration) {
+        super.onConfigurationChanged(newConfig)
+        LocaleHelper.updateCfg(this, newConfig)
+    }
+
     protected open fun setupAcra() {
         ACRA.init(this)
     }

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt

@@ -101,4 +101,6 @@ class PreferenceKeys(context: Context) {
 
     val libraryAsList = context.getString(R.string.pref_display_library_as_list)
 
+    val lang = context.getString(R.string.pref_language_key)
+
 }

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -138,4 +138,6 @@ class PreferencesHelper(context: Context) {
 
     fun downloadNew() = prefs.getBoolean(keys.downloadNew, false)
 
+    fun lang() = prefs.getInt(keys.lang, 0)
+
 }

app/src/main/java/eu/kanade/tachiyomi/ui/base/activity/BaseActivity.kt

@@ -1,9 +1,13 @@
 package eu.kanade.tachiyomi.ui.base.activity
 
 import android.support.v7.app.AppCompatActivity
+import eu.kanade.tachiyomi.util.LocaleHelper
 
 abstract class BaseActivity : AppCompatActivity(), ActivityMixin {
 
     override fun getActivity() = this
+    init {
+        LocaleHelper.updateCfg(this)
+    }
 
 }

app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

@@ -110,6 +110,8 @@ class MainActivity : BaseActivity() {
             } else if (resultCode and SettingsActivity.FLAG_THEME_CHANGED != 0) {
                 // Delay activity recreation to avoid fragment leaks.
                 nav_view.post { recreate() }
+            } else if (resultCode and SettingsActivity.FLAG_LANG_CHANGED != 0) {
+                nav_view.post { recreate() }
             }
         } else {
             super.onActivityResult(requestCode, resultCode, data)

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsActivity.kt

@@ -78,6 +78,7 @@ class SettingsActivity : BaseActivity(),
     companion object {
         const val FLAG_THEME_CHANGED = 0x1
         const val FLAG_DATABASE_CLEARED = 0x2
+        const val FLAG_LANG_CHANGED = 0x4
     }
 
 }

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralFragment.kt

@@ -9,6 +9,7 @@ import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.database.DatabaseHelper
 import eu.kanade.tachiyomi.data.library.LibraryUpdateJob
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
+import eu.kanade.tachiyomi.util.LocaleHelper
 import eu.kanade.tachiyomi.util.plusAssign
 import eu.kanade.tachiyomi.widget.preference.IntListPreference
 import eu.kanade.tachiyomi.widget.preference.LibraryColumnsDialog
@@ -17,6 +18,7 @@ import net.xpece.android.support.preference.MultiSelectListPreference
 import rx.Observable
 import rx.android.schedulers.AndroidSchedulers
 import uy.kohesive.injekt.injectLazy
+import java.util.*
 
 class SettingsGeneralFragment : SettingsFragment(),
         PreferenceFragmentCompat.OnPreferenceDisplayDialogCallback {
@@ -44,6 +46,8 @@ class SettingsGeneralFragment : SettingsFragment(),
 
     val categoryUpdate: MultiSelectListPreference by bindPref(R.string.pref_library_update_categories_key)
 
+    val langPreference: IntListPreference by bindPref(R.string.pref_language_key)
+
     override fun onViewCreated(view: View, savedState: Bundle?) {
         super.onViewCreated(view, savedState)
 
@@ -101,6 +105,15 @@ class SettingsGeneralFragment : SettingsFragment(),
             activity.recreate()
             true
         }
+
+        langPreference.setOnPreferenceChangeListener { preference, newValue ->
+            (activity as SettingsActivity).parentFlags = SettingsActivity.FLAG_LANG_CHANGED
+            LocaleHelper.setLocale(Locale(LocaleHelper.intToLangCode(newValue.toString().toInt())))
+            LocaleHelper.updateCfg(activity.application, activity.baseContext.resources.configuration)
+            activity.recreate()
+            true
+        }
+
     }
 
     override fun onPreferenceDisplayDialog(p0: PreferenceFragmentCompat?, p: Preference): Boolean {

app/src/main/java/eu/kanade/tachiyomi/util/LocaleHelper.kt

@@ -0,0 +1,48 @@
+package eu.kanade.tachiyomi.util
+
+import android.app.Application
+import android.content.res.Configuration
+import android.os.Build
+import android.view.ContextThemeWrapper
+import eu.kanade.tachiyomi.data.preference.PreferencesHelper
+import uy.kohesive.injekt.injectLazy
+import java.util.Locale
+
+
+object LocaleHelper {
+
+    private val preferences: PreferencesHelper by injectLazy()
+    private var pLocale = Locale(LocaleHelper.intToLangCode(preferences.lang()))
+
+    fun setLocale(locale: Locale) {
+        pLocale = locale
+        Locale.setDefault(pLocale)
+    }
+
+    fun updateCfg(wrapper: ContextThemeWrapper) {
+        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1){
+            val config = Configuration()
+            config.setLocale(pLocale)
+            wrapper.applyOverrideConfiguration(config)
+        }
+    }
+
+    fun updateCfg(app: Application, config: Configuration){
+        if(Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
+            config.locale = pLocale
+            app.baseContext.resources.updateConfiguration(config, app.baseContext.resources.displayMetrics)
+        }
+    }
+
+    fun intToLangCode(i: Int): String {
+        return when(i){
+            1 -> "en"
+            2 -> "es"
+            3 -> "it"
+            4 -> "pt"
+            // System Language
+            else -> ""
+        }
+    }
+
+}