private void addTextView(final String text) {
        final TextView tv = ViewUtils.createTextItem(getContext(), R.style.text_label, TextParam.text(text));
        tv.setGravity(Gravity.CENTER);
        matrixGrid.addView(tv, createLayoutParams());
    }
(re-)initializes the matrix with given data. Matrix data is deleted in the process
main/src/main/java/cgeo/geocaching/ui/CheckboxMatrixView.java