java - 单击一个菜单即可更改所有 Activity 的语言

Question

想要通过单选更改整个应用程序的语言。

MainActivity.java

 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private static Button english,russian;
    private static TextView chooseText;
    private static Locale myLocale;

//Shared Preferences Variables
private static final String Locale_Preference = "Locale Preference";
private static final String Locale_KeyValue = "Saved Locale";
private static SharedPreferences sharedPreferences;
private static SharedPreferences.Editor editor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initViews();
    setListeners();
    loadLocale();
}

//Initiate all views
private void initViews() {
    sharedPreferences = getSharedPreferences(Locale_Preference, Activity.MODE_PRIVATE);
    editor = sharedPreferences.edit();

    chooseText = (TextView) findViewById(R.id.choose_text);
    english = (Button) findViewById(R.id.english);
    russian = (Button) findViewById(R.id.russian);

}

//Set Click Listener
private void setListeners() {
    english.setOnClickListener(this);
    russian.setOnClickListener(this);

}


@Override
public void onClick(View view) {
    String lang = "en";//Default Language
    switch (view.getId()) {
        case R.id.english:
            lang = "en";
            break;
        case R.id.russian:
            lang = "ru";
            break;

    }

    changeLocale(lang);//Change Locale on selection basis
}


//Change Locale
public void changeLocale(String lang) {
    if (lang.equalsIgnoreCase(""))
        return;
    myLocale = new Locale(lang);//Set Selected Locale
    saveLocale(lang);//Save the selected locale
    Locale.setDefault(myLocale);//set new locale as default
    Configuration config = new Configuration();//get Configuration
    config.locale = myLocale;//set config locale as selected locale
    getBaseContext().getResources().updateConfiguration(config, getBaseContext().getResources().getDisplayMetrics());//Update the config
    updateTexts();//Update texts according to locale
}

//Save locale method preferences
public void saveLocale(String lang) {
    editor.putString(Locale_KeyValue, lang);
    editor.commit();
}

//Get locale method in preferences
public void loadLocale() {
    String language = sharedPreferences.getString(Locale_KeyValue, "");
    changeLocale(language);
}

//Update text methods
private void updateTexts() {
    chooseText.setText(R.string.tap_text);
    english.setText(R.string.btn_en);
    russian.setText(R.string.btn_ru);

  }
}

我可以使用上面的代码更改单个 Activity 语言。但我想单击一次更改所有应用程序语言。请帮助我这样做。我正在尝试允许从设备设置访问语言

Answer 1

创建一个类 LocalHelper.java 来管理您的应用程序的本地化。

public class LocaleHelper {

    private static final String SELECTED_LANGUAGE = "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;
    }
}

并且在您的应用程序类中，您需要覆盖 attachBaseContext 并调用 LocaleHelper.onAttach() 来初始化应用程序中的语言环境设置。

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

每当您的语言发生变化时，您需要调用

LocaleHelper.setLocale(this, yourNewLanguageCode);

这将更改所有其他 Activity ，但不会更改您更改语言的 Activity 。因此，您需要重新创建该 Activity 或更新该 Activity 的 View 。

要重新创建 Activity ，请调用

startActivity(new Intent(CurrentActivity.this, CurrentActivity.class))
finish();

如果您想更新 View 而不是重新创建 Activity ，请使用从 LocaleHelper.setLocale(this, yourNewLanguageCode)

返回的 context

Context context = LocaleHelper.setLocale(this, languageCode);
Resources resources = context.getResources();

textView.setText(resources.getString(R.string.textTitle));

注意:在 Android API 版本 24(Nougat) 之后，您需要覆盖所有 Activity 中的 attachBaseContext 以反射(reflect)更改。