在Android <9中控制android底部导航视图的文本大小

<style name="BottomNavigationViewStyle" parent="Widget.Design.BottomNavigationView">
    <item name="android:textSize">12sp</item> <!-- 设置文本大小，这里设置为12sp -->
</style>

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:id="@+id/bottomNavigationView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    style="@style/BottomNavigationViewStyle" />

BottomNavigationView bottomNavigationView = findViewById(R.id.bottomNavigationView);
Menu menu = bottomNavigationView.getMenu();
for (int i = 0; i < menu.size(); i++) {
    MenuItem menuItem = menu.getItem(i);
    SpannableString spannableString = new SpannableString(menuItem.getTitle());
    spannableString.setSpan(new AbsoluteSizeSpan(12, true), 0, spannableString.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE);
    menuItem.setTitle(spannableString);
}