Custom TextSize of BottomNavigationView support android

Question

I am trying to change the textSize of BottomNavigationView from android support library 25.0.0

Answer 1

Another solution is to use Spannable to adjust the size color, font or other a text attributes ....

private static class MenuSpannable extends MetricAffectingSpan{
        int color = Color.RED;
        int size = 40;

        public MenuSpannable() {
            setSelected(false);
        }

        @Override
        public void updateMeasureState(TextPaint p) {
            p.setColor(color);
            p.setTextSize(size);
            /* p.setText --- whatever --- */
        }

        @Override
        public void updateDrawState(TextPaint tp) {
            tp.setColor(color);
            tp.setTextSize(size);
            /* tp.setText --- whatever --- */
        }
        private void setSelected(boolean selected){
            if(selected){
                color = Color.RED;
                size = 40;
            }else{
                color = Color.BLUE;
                size = 20;
            }
        }
}

And then set the span for any menu item...

@Override
protected void onCreate(Bundle savedInstanceState) {
        BottomNavigationView mBottomNavigationView = (BottomNavigationView)findViewById(R.id.bottom_menu);
        final Menu menu = mBottomNavigationView.getMenu();
        final Font font = Font.getFromContext(this);
        for(int i = 0; i < menu.size(); i++) {
            SpannableString spannableString = new SpannableString(menu.getItem(i).getTitle());
            spannableString.setSpan(new MenuSpannable(),0,spannableString.length(),0);
            menu.getItem(i).setTitle(spannableString);
        }
}

In case you want the text to change with the selection state

mBottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
             Menu menu = mBottomNavigationView.getMenu();
             for(int i = 0; i < menu.size(); i++) {
                MenuSpannable menuSpannable = new MenuSpannable();
                menuSpannable.setSelected(item.getItemId() == menu.getItem(i).getItemId());
                SpannableString sString = new SpannableString(menu.getItem(i).getTitle());
                sString.setSpan(menuSpannable,0,sString.length(),0);
                menu.getItem(i).setTitle(sString);
                }
            return false;
            }
        });