是这里的原因吗

if(cursor !=null){
    while(cursor.moveToNext()){
        CostBean costBean = new CostBean();
        costBean.costTitle = cursor.getString(cursor.getColumnIndex("cost_title"));
        costBean.costDate = cursor.getString(cursor.getColumnIndex("cost_date"));
        costBean.costMoney = cursor.getString(cursor.getColumnIndex("cost_money"));
        mCostBeanList.add(costBean);
    }