Mayuri的答案是正确的，但这只适用于Api 33或更高的版本。以下是逐步向后兼容的解决方案:

步骤1:在res/xml文件夹下创建locales_config.xml。

//res/xml/locales_config.xml
<?xml version="1.0" encoding="utf-8"?>
<locale-config xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Add your required languages -->
    <locale android:name="hi" />
    <locale android:name="en" />
</locale-config>

步骤2:在Application的Manifest中添加localeConfig

<manifest>
<application
    android:localeConfig="@xml/locales_config">
</application>

步骤3:在Manifest中应用此服务

<service
android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
android:enabled="false"
android:exported="false">
<meta-data
  android:name="autoStoreLocales"
  android:value="true" />
</service>

步骤4:在应用程序的模块级构建中使用resConfigs属性指定相同的语言。gradle文件:

  android {
  defaultConfig {
      ...
      resConfigs "hi","en"
  }
  }

(要求appCompat版本1.6.0或更高)

implementation 'androidx.appcompat:appcompat:1.6.0'

第5步:现在你可以使用下面的代码来更改应用程序语言(在android 9,10,12和13上测试)

  LocaleListCompat appLocale = LocaleListCompat.forLanguageTags("hi"); //Give user selected language code 
  AppCompatDelegate.setApplicationLocales(appLocale);

androidx。Appcompat: Appcompat用户，以上解决方案将在1.3.0版本后工作。 就像这里提到的。

这段代码真的可以工作:

fa = 波斯语，en = 英语

注意:语言代码不能有“-”，必须是2个小写字母

在languageToLoad变量中输入您的语言代码:

import android.app.Activity;
import android.content.res.Configuration;
import android.os.Bundle;

public class Main extends Activity {
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    String languageToLoad  = "fa"; // your language
    Locale locale = new Locale(languageToLoad); 
    Locale.setDefault(locale);
    Configuration config = new Configuration();
    config.locale = locale;
    getBaseContext().getResources().updateConfiguration(config, 
      getBaseContext().getResources().getDisplayMetrics());
    this.setContentView(R.layout.main);
  }
}

---

2021年6月更新(Kotlin):

class Main : Activity() {
    // Called when the activity is first created.
    public override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        val config = resources.configuration
        val lang = "fa" // your language code
        val locale = Locale(lang)
        Locale.setDefault(locale)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1)
            config.setLocale(locale)
        else
            config.locale = locale

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
            createConfigurationContext(config)
        resources.updateConfiguration(config, resources.displayMetrics)

        this.setContentView(R.layout.main)
    }
}

我知道现在回答有点晚了，但我在这里找到了这篇文章 ． 它很好地解释了整个过程，并为您提供了结构良好的代码。

Locale Helper类:

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;

/**
 * This class is used to change your application locale and persist this change for the next time
 * that your app is going to be used.
 * <p/>
 * You can also change the locale of your application on the fly by using the setLocale method.
 * <p/>
 * Created by gunhansancar on 07/10/15.
 */
public class LocaleHelper {

    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;
    }
}

您需要重写attachBaseContext并调用LocaleHelper.onAttach()来初始化应用程序中的语言环境设置。

import android.app.Application;
import android.content.Context;

import com.gunhansancar.changelanguageexample.helper.LocaleHelper;

public class MainApplication extends Application {
    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(LocaleHelper.onAttach(base, "en"));
    }
}

你所要做的就是相加

LocaleHelper.onCreate(this, "en");

只要你想改变locale。

是时候更新了。

首先，弃用列表和它被弃用的API:

配置。locale (API 17) updateConfiguration(配置，displaymetrics) (API 17)

最近没有问题的答案是正确的是新方法的使用。

createconfigationcontext是updateConfiguration的新方法。

有些人是这样独立使用的:

Configuration overrideConfiguration = ctx.getResources().getConfiguration();
Locale locale = new Locale("en_US");
overrideConfiguration.setLocale(locale);
createConfigurationContext(overrideConfiguration);

．.． 但这行不通。为什么?该方法返回一个上下文，然后用于处理Strings.xml翻译和其他本地化资源(图像、布局等)。

正确用法是这样的:

Configuration overrideConfiguration = ctx.getResources().getConfiguration();
Locale locale = new Locale("en_US");
overrideConfiguration.setLocale(locale);
//the configuration can be used for other stuff as well
Context context  = createConfigurationContext(overrideConfiguration);
Resources resources = context.getResources();

如果您只是复制粘贴到您的IDE中，您可能会看到一个警告，该API要求您针对API 17或更高版本。这可以通过将它放在一个方法中并添加注释@TargetApi(17)来解决。

但是等待。那么旧的API呢?

您需要在没有TargetApi注释的情况下使用updateConfiguration创建另一个方法。

Resources res = YourApplication.getInstance().getResources();
// Change locale settings in the app.
DisplayMetrics dm = res.getDisplayMetrics();
android.content.res.Configuration conf = res.getConfiguration();
conf.locale = new Locale("th");
res.updateConfiguration(conf, dm);

这里不需要返回上下文。

现在，管理这些可能很困难。在API 17+中，你需要创建上下文(或者创建上下文中的资源)来获得基于本地化的适当资源。你如何处理这个问题?

好吧，我是这么做的:

/**
 * Full locale list: https://stackoverflow.com/questions/7973023/what-is-the-list-of-supported-languages-locales-on-android
 * @param lang language code (e.g. en_US)
 * @return the context
 * PLEASE READ: This method can be changed for usage outside an Activity. Simply add a COntext to the arguments
 */
public Context setLanguage(String lang/*, Context c*/){
    Context c = AndroidLauncher.this;//remove if the context argument is passed. This is a utility line, can be removed totally by replacing calls to c with the activity (if argument Context isn't passed)
    int API = Build.VERSION.SDK_INT;
    if(API >= 17){
        return setLanguage17(lang, c);
    }else{
        return setLanguageLegacy(lang, c);
    }
}

/**
 * Set language for API 17
 * @param lang
 * @param c
 * @return
 */
@TargetApi(17)
public Context setLanguage17(String lang, Context c){
    Configuration overrideConfiguration = c.getResources().getConfiguration();
    Locale locale = new Locale(lang);
    Locale.setDefault(locale);
    overrideConfiguration.setLocale(locale);
    //the configuration can be used for other stuff as well
    Context context  = createConfigurationContext(overrideConfiguration);//"local variable is redundant" if the below line is uncommented, it is needed
    //Resources resources = context.getResources();//If you want to pass the resources instead of a Context, uncomment this line and put it somewhere useful
    return context;
}

public Context setLanguageLegacy(String lang, Context c){
    Resources res = c.getResources();
    // Change locale settings in the app.
    DisplayMetrics dm = res.getDisplayMetrics();//Utility line
    android.content.res.Configuration conf = res.getConfiguration();

    conf.locale = new Locale(lang);//setLocale requires API 17+ - just like createConfigurationContext
    Locale.setDefault(conf.locale);
    res.updateConfiguration(conf, dm);

    //Using this method you don't need to modify the Context itself. Setting it at the start of the app is enough. As you
    //target both API's though, you want to return the context as you have no clue what is called. Now you can use the Context
    //supplied for both things
    return c;
}

This code works by having one method that makes calls to the appropriate method based on what API. This is something I have done with a lot of different deprecated calls (including Html.fromHtml). You have one method that takes in the arguments needed, which then splits it into one of two (or three or more) methods and returns the appropriate result based on API level. It is flexible as you do't have to check multiple times, the "entry" method does it for you. The entry-method here is setLanguage

使用前请仔细阅读

您需要使用获取资源时返回的Context。为什么?我在这里看到了其他使用createconfigationcontext而不使用它返回的上下文的答案。为了让它这样工作，必须调用updateConfiguration。这是不赞成的。使用方法返回的上下文来获取资源。

使用示例:

构造函数或类似的地方:

ctx = getLanguage(lang);//lang is loaded or generated. How you get the String lang is not something this answer handles (nor will handle in the future)

然后，无论你想在哪里获得资源，你都可以:

String fromResources = ctx.getString(R.string.helloworld);

使用任何其他上下文(理论上)都会打破这一点。

AFAIK，你仍然需要使用活动上下文来显示对话框或toast。为此，您可以使用一个活动的实例(如果您在外部)

---

最后，在活动上使用rebuild()来刷新内容。快捷方式可以不用创建意图刷新。

如果你想在你的应用中保持语言变化，你必须做两件事。

首先，创建一个base Activity，让你所有的Activity都从下面扩展:

public class BaseActivity extends AppCompatActivity {

    private Locale mCurrentLocale;

    @Override
    protected void onStart() {
        super.onStart();

        mCurrentLocale = getResources().getConfiguration().locale;
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Locale locale = getLocale(this);

        if (!locale.equals(mCurrentLocale)) {

            mCurrentLocale = locale;
            recreate();
        }
    }

    public static Locale getLocale(Context context){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);

        String lang = sharedPreferences.getString("language", "en");
        switch (lang) {
            case "English":
                lang = "en";
                break;
            case "Spanish":
                lang = "es";
                break;
        }
        return new Locale(lang);
    }
}

注意，我将新语言保存在sharedPreference中。

其次，像这样创建一个应用程序的扩展:

    public class App extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        setLocale();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        setLocale();
    }

    private void setLocale() {

        final Resources resources = getResources();
        final Configuration configuration = resources.getConfiguration();
        final Locale locale = getLocale(this);
        if (!configuration.locale.equals(locale)) {
            configuration.setLocale(locale);
            resources.updateConfiguration(configuration, null);
        }
    }
}

注意，getLocale()与上面相同。

这是所有! 我希望这能帮助到一些人。