Android TimePicker with custom Locale.

_LocaleTimePicker.java

public class LocaleTimePicker extends TimePicker {

    public LocaleTimePicker(Context context) {
        this(context, null);
    }

    public LocaleTimePicker(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, Resources.getSystem().getIdentifier("timePickerStyle", "attr", "android"));
    }

    public LocaleTimePicker(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(new ContextLocaleWrapper(context, getLocaleFromAttrs(context, attrs, defStyleAttr), true), attrs, defStyleAttr);

        ((ContextLocaleWrapper) getContext()).resetDefaultLocale();
    }

    private static @Nullable Locale getLocaleFromAttrs(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.LocaleTimePicker, defStyleAttr, 0);
        String lang = a.getString(R.styleable.LocaleTimePicker_locale);
        a.recycle();
        if (lang != null) {
            return new Locale(lang);
        } else {
            return null;
        }
    }

    private static class ContextLocaleWrapper extends ContextThemeWrapper {

        @Nullable
        private Locale defaultLocale = null;

        private ContextLocaleWrapper(Context context, Locale locale) {
            this(context, locale, false);
        }

        private ContextLocaleWrapper(Context context, Locale locale, boolean overwriteDefaultLocale) {
            super(context, context.getTheme());

            Configuration configuration = new Configuration(context.getResources().getConfiguration());
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                configuration.setLocale(locale);
                configuration.setLayoutDirection(locale);
            } else {
                configuration.locale = locale;
            }
            applyOverrideConfiguration(configuration);

            // For prior to Android N, overwrite default Locale
            if (overwriteDefaultLocale
                    && Build.VERSION.SDK_INT < Build.VERSION_CODES.N
                    && !Locale.getDefault().equals(defaultLocale)) {
                defaultLocale = Locale.getDefault();
                Locale.setDefault(locale);
            }
        }

        public void resetDefaultLocale() {
            // For prior to Android N, reset the overwritten default Locale
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N && defaultLocale != null) {
                Locale.setDefault(defaultLocale);
            }
        }
    }
}

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="LocaleTimePicker">
        <attr format="string" name="locale"/>
    </declare-styleable>
</resources>

layout.xml

<xxx.LocaleTimePicker
    android:id="@+id/time_picker"
    ...
    app:locale="ja"
    />