public void executeFor(final int row, final int col, final Action2<Integer, Integer> action) {
        for (int r = (Math.max(row, 0)); r < (row < 0 ? rows.length : row + 1); r++) {
            for (int c = (Math.max(col, 0)); c < (col < 0 ? cols.length : col + 1); c++) {
                action.call(r, c);
            }
        }
    }
Convevience method to execute an action on multiple matrix fields.
- When row and col are >=0, change will be executed on specific field.
- When row or col is <0 and the other one is >=0 then change will be executed for all fields in specific row/col
- When both row and col are <0 then change will be executed for all fields
main/src/main/java/cgeo/geocaching/ui/CheckboxMatrixView.java