loading saved .xml file in android

edit

this is my load .xml code but error occured

public Mat readmat(String tag){
    if( isWrite ) {
        System.err.println("Try read from file with write flags");
        return null;
    }

    NodeList nodelist = doc.getElementsByTagName(tag);
    Mat readMat = null;

    for( int i = 0 ; i<nodelist.getLength() ; i++ ){
        Node node = nodelist.item(i);

        if( node.getNodeType() == Node.ELEMENT_NODE ) {
            Element element = (Element)node;

            String type_id = element.getAttribute("type_id");
            if( "opencv-matrix".equals(type_id) == false) {
                System.out.println("Fault type_id ");
            }

            String rowsStr = element.getElementsByTagName("rows").item(0).getTextContent();
            String colsStr = element.getElementsByTagName("cols").item(0).getTextContent();
            String dtStr = element.getElementsByTagName("dt").item(0).getTextContent();
            String dataStr = element.getElementsByTagName("data").item(0).getTextContent();

            int rows = Integer.parseInt(rowsStr);
            int cols = Integer.parseInt(colsStr);
            int type = CvType.CV_8U;
            if( "d".equals(dtStr) ) {
                type = CvType.CV_64F;
                readMat = new Mat( rows, cols, type );
                byte[] data = Base64.decode(dataStr.getBytes(), Base64.DEFAULT);
                Log.i("FC_MainAct", ""+data.length);

                readMat.put(0, 0, data);
            }
        }
    }
    return readMat;

and this is my log