well, it seems that your .split returns 7 tokens. Your str[] is zero-indexed. how about you try doing
contentValues.put("order_date", str[0]);
contentValues.put("cust_code", str[1]);
contentValues.put("customer_ref", str[2]);
contentValues.put("line_no", str[3]);
contentValues.put("item_code", str[4]);
contentValues.put("tran_code", str[5]);
contentValues.put("order_qty", str[6]);
db.insert(tableName, null, contentValues);
make it run from str[0] to str[6]