How to use Calligraphy with multi-language support Oreo

Question

I'm developing an app that need to support multiple languages and if the language is RTL I have to apply a custom font. For the requirement I have created my Class that extends Application. Everything was perfect till I got Oreo version device (Before I have Marshmellow enabled device). In Oreo if we want to change the language we have to create a custom ContextWrapper class, here problem come in.

1. To use Calligraphy we need to Override the attachBaseContext method. And
2. To change language we need to Override the attachBaseContext too

I tried to call super.attachBaseContext in the Overrided method twice One for the Calligraphy and Other for the Language code like below.

@Override
protected void attachBaseContext(Context newBase) {

    // create or get your new Locale object here.
    String lang = Preferences
            .getSharedPreferenceString(appContext, LANGUAGE_KEY, "ar");

    Context context = MyContextWrapper.wrap(newBase, lang);
    super.attachBaseContext(context);
    super.attachBaseContext(CalligraphyContextWrapper.wrap(newBase));
}

It give IllegalStateException as we can attach base context once.

• If I use super.attachBaseContext(context); the language change works But Calligraphy does not.
• If I use super.attachBaseContext(CalligraphyContextWrapper.wrap(newBase)); Calligraphy works But Language change does not.

In such case how can I make all working (Calligraphy + Multi-language). I have viewed many posts/tutorials but I'm stuck in this for three days now.

Please help me complete this. Thanks

Edit: References

1. CalligraphyContextWrapper.java
2. ContextWrapper Class Accepted answer in link.

Looking for a solution to be able to use custom font with Calligraphy and Change Language Functionality. Alternatively provide a way so that I may be able to change Language and Apply Font to the whole app.

Note: The solution must be compatible with API 17 to the latest 27. I'm using AppCompat.

Answer 1

I have done it for oreo

In your activity:

@Override
protected void attachBaseContext(Context newBase) {
    super.attachBaseContext(CalligraphyContextWrapper.wrap(SLocaleHelper.onAttach(newBase)));
}

OR

@Override
    protected void attachBaseContext(Context newBase) {
    super.attachBaseContext(ViewPumpContextWrapper.wrap(SLocaleHelper.onAttach(newBase)));
    }

In your application main class:

@Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(SLocaleHelper.onAttach(base, "sv"));
        MultiDex.install(this);
    }

Locale helper Class:

package com.......;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.preference.PreferenceManager;

import java.util.Locale;

public class SLocaleHelper {

    private static final String SELECTED_LANGUAGE = "Locale.Helper.Selected.Language";

    public static Context onAttach(Context context) {
        String lang = getPersistedData(context, Locale.getDefault().getLanguage());
        return setLocale(context, lang);
    }

    public static Context onAttach(Context context, String defaultLanguage) {
        String lang = getPersistedData(context, defaultLanguage);
        return setLocale(context, lang);
    }

    public static String getLanguage(Context context) {
        return getPersistedData(context, Locale.getDefault().getLanguage());
    }

    public static Context setLocale(Context context, String language) {
        persist(context, language);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            return updateResources(context, language);
        }

        return updateResourcesLegacy(context, language);
    }

    private static String getPersistedData(Context context, String defaultLanguage) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        return preferences.getString(SELECTED_LANGUAGE, defaultLanguage);
    }

    private static void persist(Context context, String language) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = preferences.edit();

        editor.putString(SELECTED_LANGUAGE, language);
        editor.apply();
    }

    @TargetApi(Build.VERSION_CODES.N)
    private static Context updateResources(Context context, String language) {
        Locale locale = new Locale(language);
        Locale.setDefault(locale);

        Configuration configuration = context.getResources().getConfiguration();
        configuration.setLocale(locale);
        configuration.setLayoutDirection(locale);

        return context.createConfigurationContext(configuration);
    }

    @SuppressWarnings("deprecation")
    private static Context updateResourcesLegacy(Context context, String language) {
        Locale 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;
    }
}

Answer 2

@Override
protected void attachBaseContext(Context newBase) {
    ContextWrapper localeContextWrapper = LocaleManager.wrap(newBase, "en");
    ContextWrapper calligraphyContextWrapper = CalligraphyContextWrapper.wrap(localeContextWrapper);
    super.attachBaseContext(calligraphyContextWrapper);
}

LocaleManager.java

public class LocaleManager {
    public static ContextWrapper wrap(Context context, String language) {
        Resources res = context.getResources();
        Configuration configuration = res.getConfiguration();
        Locale newLocale = new Locale(language);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            configuration.setLocale(newLocale);
            LocaleList localeList = new LocaleList(newLocale);
            LocaleList.setDefault(localeList);
            configuration.setLocales(localeList);
            context = context.createConfigurationContext(configuration);

        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            configuration.setLocale(newLocale);
            context = context.createConfigurationContext(configuration);

        } else {
            configuration.locale = newLocale;
            res.updateConfiguration(configuration, res.getDisplayMetrics());
        }

        return new ContextWrapper(context);
    }
}