private void processFormulaChange() {
        ensureFormula();
        if (this.formulaChangeListener != null) {
            final String formulaString = ViewUtils.getEditableText(binding.formulaText.getText());
            this.formulaChangeListener.accept(formulaString, formula);
        }
    }
Allows live-editing of a formula, optionally associated with a Variable List
main/src/main/java/cgeo/geocaching/ui/FormulaEditText.java