Application.java

/**
 * 设置国家语言
 * @param language
 */
public static void selectLanguage(Context minContext , String language) {
    Log.i("cs","selectLanguage="+language);
    Locale targetLocale = null;
    switch (language) {
        case "en_us": //英语
            targetLocale = Locale.ENGLISH;
            break;
        case "zh_cn": //简体中文
            targetLocale = Locale.SIMPLIFIED_CHINESE;
            break;
        case "zh_tw": //繁体中文
            targetLocale = Locale.TAIWAN;
            break;
        default: //默认繁体
            targetLocale = Locale.TAIWAN;
            //targetLocale = Locale.getDefault();
            Log.i("cs","进入了默认语言"+language);
            break;
    }
    Configuration configuration = context.getResources().getConfiguration();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
        configuration.setLocale(targetLocale);
    } else {
        configuration.locale = targetLocale;
    }
    Resources resources = context.getResources();
    DisplayMetrics dm = resources.getDisplayMetrics();
    resources.updateConfiguration(configuration, dm);//语言更换生效的代码!
    //保存设置语言的类型
    SharedPreferencesUtils.putInfo(context,"language", language);
}

BaseActivity.java

@Override
protected void attachBaseContext(Context context) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        String language = SharedPreferencesUtils.getPreferences(this).getString("language","");
        Locale targetLocale = null;
        switch (language) {
            case "en_us": //英语
                targetLocale = Locale.ENGLISH;
                break;
            case "zh_cn": //简体中文
                targetLocale = Locale.SIMPLIFIED_CHINESE;
                break;
            case "zh_tw": //繁体中文
                targetLocale = Locale.TAIWAN;
                break;
            default: //默认繁体
                targetLocale = Locale.TAIWAN;
                //targetLocale = Locale.getDefault();
                Log.i("cs","进入了默认语言"+language);
                break;
        }
        Resources resources = context.getResources();
        Configuration configuration = resources.getConfiguration();
        Locale locale=targetLocale;
        configuration.setLocale(locale);
        context = context.createConfigurationContext(configuration);
    } else {
        // 这里是调用
        MyApplication.selectLanguage(this,SharedPreferencesUtils.getPreferences(this).getString("language",""));
    }
    super.attachBaseContext(context);
}

别人写的帮助类

public class MultiLanguageUtil {

    private static final String TAG = "MultiLanguageUtil";
    private static MultiLanguageUtil instance;
    private Context mContext;
    public static final String SAVE_LANGUAGE = "save_language";

    public static void init(Context mContext) {
        if (instance == null) {
            synchronized (MultiLanguageUtil.class) {
                if (instance == null) {
                    instance = new MultiLanguageUtil(mContext);
                }
            }
        }
    }

    public static MultiLanguageUtil getInstance() {
        if (instance == null) {
            throw new IllegalStateException("You must be init MultiLanguageUtil first");
        }
        return instance;
    }

    private MultiLanguageUtil(Context context) {
        this.mContext = context;
    }

    /**
     * 设置语言
     */
    public void setConfiguration() {
        Locale targetLocale = getLanguageLocale();
        Configuration configuration = mContext.getResources().getConfiguration();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            configuration.setLocale(targetLocale);
        } else {
            configuration.locale = targetLocale;
        }
            Resources resources = mContext.getResources();
            DisplayMetrics dm = resources.getDisplayMetrics();
            resources.updateConfiguration(configuration, dm);//语言更换生效的代码!
    }

    /**
     * 如果不是英文、简体中文、繁体中文,默认返回简体中文
     *
     * @return
     */
    private Locale getLanguageLocale() {
        int languageType = CommSharedUtil.getInstance(mContext).getInt(MultiLanguageUtil.SAVE_LANGUAGE, 0);
        if (languageType == LanguageType.LANGUAGE_FOLLOW_SYSTEM) {
            Locale sysLocale= getSysLocale();
            return sysLocale;
        } else if (languageType == LanguageType.LANGUAGE_EN) {
            return Locale.ENGLISH;
        } else if (languageType == LanguageType.LANGUAGE_CHINESE_SIMPLIFIED) {
            return Locale.SIMPLIFIED_CHINESE;
        } else if (languageType == LanguageType.LANGUAGE_CHINESE_TRADITIONAL) {
            return Locale.TRADITIONAL_CHINESE;
        }
        getSystemLanguage(getSysLocale());
        Log.e(TAG, "getLanguageLocale" + languageType + languageType);
        return Locale.SIMPLIFIED_CHINESE;
    }

    private String getSystemLanguage(Locale locale) {
        return locale.getLanguage() + "_" + locale.getCountry();

    }

    //以上获取方式需要特殊处理一下
    public Locale getSysLocale() {
        Locale locale;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            locale = LocaleList.getDefault().get(0);
        } else {
            locale = Locale.getDefault();
        }
        return locale;
    }

    /**
     * 更新语言
     *
     * @param languageType
     */
    public void updateLanguage(int languageType) {
        CommSharedUtil.getInstance(mContext).putInt(MultiLanguageUtil.SAVE_LANGUAGE, languageType);
        MultiLanguageUtil.getInstance().setConfiguration();
        EventBus.getDefault().post(new OnChangeLanguageEvent(languageType));
    }

    public String getLanguageName(Context context) {
        int languageType = CommSharedUtil.getInstance(context).getInt(MultiLanguageUtil.SAVE_LANGUAGE,LanguageType.LANGUAGE_FOLLOW_SYSTEM);
        if (languageType == LanguageType.LANGUAGE_EN) {
            return mContext.getString(R.string.setting_language_english);
        } else if (languageType == LanguageType.LANGUAGE_CHINESE_SIMPLIFIED) {
            return mContext.getString(R.string.setting_simplified_chinese);
        } else if (languageType == LanguageType.LANGUAGE_CHINESE_TRADITIONAL) {
            return mContext.getString(R.string.setting_traditional_chinese);
        }
        return mContext.getString(R.string.setting_language_auto);
    }

    /**
     * 获取到用户保存的语言类型
     * @return
     */
    public int getLanguageType() {
        int languageType = CommSharedUtil.getInstance(mContext).getInt(MultiLanguageUtil.SAVE_LANGUAGE, LanguageType.LANGUAGE_FOLLOW_SYSTEM);
         if (languageType == LanguageType.LANGUAGE_CHINESE_SIMPLIFIED) {
            return LanguageType.LANGUAGE_CHINESE_SIMPLIFIED;
        } else if (languageType == LanguageType.LANGUAGE_CHINESE_TRADITIONAL) {
            return LanguageType.LANGUAGE_CHINESE_TRADITIONAL;
        } else if (languageType == LanguageType.LANGUAGE_FOLLOW_SYSTEM) {
           return LanguageType.LANGUAGE_FOLLOW_SYSTEM;
        }
        Log.e(TAG, "getLanguageType" + languageType);
        return languageType;
    }

    public static Context attachBaseContext(Context context) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            return createConfigurationResources(context);
        } else {
            MultiLanguageUtil.getInstance().setConfiguration();
            return context;
        }
    }

    @TargetApi(Build.VERSION_CODES.N)
    private static Context createConfigurationResources(Context context) {
        Resources resources = context.getResources();
        Configuration configuration = resources.getConfiguration();
        Locale locale=getInstance().getLanguageLocale();
        configuration.setLocale(locale);
        return context.createConfigurationContext(configuration);
    }
}

记APP实现多语言(国际化)过程,兼容Android 8.0以上
Android国际化(多语言)实现,支持8.0+
MultiLanguages
AndroidMultiLanguage