public void setIndicatorFormatter(@Nullable String formatter) {
        mIndicatorFormatter = formatter;
        updateProgressMessage(mValue);
    }
Sets the current Indicator formatter string

@param formatter
@see String#format(String, Object...)
@see #setNumericTransformer(NumericTransformer)
app/src/main/java/com/duan/musicoco/view/discreteseekbar/DiscreteSeekBar.java