public String getId() {
        final String formatRow = String.format("%03d", row);
        final String formatColumn = String.format("%03d", column);
        return formatRow + "-" + formatColumn;
    }
Gets the ID.It is counted from left to right, top to bottom of the
matrix, starting by zero.

@return the ID.
android-patternview/src/main/java/com/eftimoff/patternview/cells/Cell.java