Text Input Filter to limit the number of decimal places

DecimalPlacesFilter.java

package com.mindscollide.baycho.utils;

import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.DigitsKeyListener;

/**
 * Created by Zuhaib on 5/11/2017.
 * <p>
 * Text {@link android.text.InputFilter} to limit the number of decimal places
 */

public class DecimalPlacesFilter extends DigitsKeyListener {

	private int mDigits = 2;

	/**
	 * Returns new instance of {@link DecimalPlacesFilter}
	 *
	 * @param decimalPlaces The number of decimal places allowed
	 * @param isSigned      The flag for value being signed
	 */
	public DecimalPlacesFilter(int decimalPlaces, boolean isSigned) {
		super(isSigned, true);
		mDigits = decimalPlaces;
	}

	/**
	 * Sets the decimal places limit
	 *
	 * @param decimalPlaces The number of decimal places allowed
	 */
	public void setDigits(int decimalPlaces) {
		mDigits = decimalPlaces;
	}

	@Override
	public CharSequence filter(CharSequence source, int sourceStart, int sourceEnd,
							   Spanned destination, int destStart, int destEnd) {

		final CharSequence text = super.filter(source, sourceStart,
				sourceEnd, destination, destStart, destEnd);

		// if changed, replace the source 
		if (text != null) {
			source = text;
			sourceStart = 0;
			sourceEnd = text.length();
		}

		int sourceLength = sourceEnd - sourceStart;

		// return if text is empty
		if (sourceLength == 0) {
			return source;
		}

		int destLength = destination.length();

		// Find the position of the decimal . 
		for (int currentLocation = 0; currentLocation < destStart; currentLocation++) {
			if (destination.charAt(currentLocation) == '.') {
				// Being here means, that a number has been inserted after the dot
				// Check if the amount of digits is right
				return (destLength - (currentLocation + 1) + sourceLength > mDigits)
						? ""
						: new SpannableStringBuilder(source, sourceStart, sourceEnd);
			}
		}

		for (int i = sourceStart; i < sourceEnd; ++i) {
			if (source.charAt(i) == '.') {
				// Being here means, dot has been inserted
				// Check if the amount of mDigits is right
				if ((destLength - destEnd) + (sourceEnd - (i + 1)) > mDigits)
					return "";
				else
					break;
			}
		}

		// If the dot is after the inserted part, nothing can break
		return new SpannableStringBuilder(source, sourceStart, sourceEnd);
	}
}