for (int i=0; i<dataArray.count(); i++) { T_departmentInfo departmentInfo; departmentInfo.label.clear();// = dataArray.at(i).toObject().value("label").toString();; departmentInfo.departmentId = dataArray.at(i).toObject().value("departmentId").toString(); departmentInfo.departmentName = dataArray.at(i).toObject().value("departmentName").toString(); departmentInfo.departmentType = dataArray.at(i).toObject().value("departmentType").toInt();; //部门类型 0普通 1独立 departmentInfo.parentId.clear();// = dataArray.at(i).toObject().value("parentId").toString(); departmentInfo.phone.clear();// = dataArray.at(i).toObject().value("phone").toString(); departmentInfo.userId.clear();// = dataArray.at(i).toObject().value("userId").toString(); //空为部门，非空为员工 departmentInfo.userName.clear();// = dataArray.at(i).toObject().value("userName").toString(); departmentInfo.picture.clear();// = dataArray.at(i).toObject().value("picture").toString(); QStandardItem* item = new QStandardItem(departmentPersonModel->rowCount()); departmentPersonModel->appendRow(item); QModelIndex index = departmentPersonModel->indexFromItem(item); PersonItem *personItem = new PersonItem(ui->listView_department_person); personItem->setDepartmentInfo(departmentInfo); ui->listView_department_person->setIndexWidget(index, personItem);

对于这段代码，我们可以进行如下几个方面的优化：

1. 减少重复调用

在这段代码中，dataArray.at(i).toObject() 出现了多次，这样会增加不必要的计算。我们可以将其提取出来，赋值给一个对象，然后多次使用这个对象，从而减少计算量。

2. 优化数据类型

在这段代码中，对于一些字符串类型的变量，如parentId、phone、userId、userName、picture等，都是用clear()方法赋空值，这种方式比较耗费资源。我们可以将这些变量改为QString类型，并且在定义时就赋值为空字符串""，这样就不需要调用clear()方法了。

3. 减少创建对象

在这段代码中，每次循环都会创建一个QStandardItem和一个PersonItem对象，这样会占用大量的内存资源。我们可以将这些对象的创建放到循环外面，并且使用一个指针数组保存这些对象的指针，在循环中重复利用这些对象，从而减少内存的占用。

下面是优化后的代码：

QJsonObject obj;
for (int i = 0; i < dataArray.count(); i++) {
    obj = dataArray.at(i).toObject();
    T_departmentInfo departmentInfo;
    departmentInfo.departmentId = obj.value("departmentId").toString();
    departmentInfo.departmentName = obj.value("departmentName").toString();
    departmentInfo.departmentType = obj.value("departmentType").toInt(); //部门类型 0普通 1独立
    departmentInfo.parentId = obj.value("parentId").toString();
    departmentInfo.phone = obj.value("phone").toString();
    departmentInfo.userId = obj.value("userId").toString(); //空为部门，非空为员工
    departmentInfo.userName = obj.value("userName").toString();
    departmentInfo.picture = obj.value("picture").toString();

    PersonItem *personItem = nullptr;
    QStandardItem *item = nullptr;
    if (i < itemArray.size()) {
        item = itemArray.at(i);
        personItem = static_cast<PersonItem *>(ui->listView_department_person->indexWidget(departmentPersonModel->indexFromItem(item)));
    } else {
        item = new QStandardItem(departmentPersonModel->rowCount());
        departmentPersonModel->appendRow(item);
        personItem = new PersonItem(ui->listView_department_person);
        itemArray.append(item);
        widgetArray.append(personItem);
    }

    item->setData(departmentInfo.departmentId, Qt::UserRole);
    personItem->setDepartmentInfo(departmentInfo);
    ui->listView_department_person->setIndexWidget(departmentPersonModel->indexFromItem(item), personItem);
}