从数据库中填充 QTreeView 作为父节点和子节点

Question

我在数据库的以下列中存储了数据

|AcName|ActCod|GroupCode|

|parent1| |1|   |0|

|child1|  |101| |1|

|parent2| |2|   |0|

|child2|  |201| |2|

我正在使用 QTreeView、QStandardItemModel 和 QStandardItem 来创建此树视图，但是我不知道如何将子视图附加到父视图。我将 QStandardItem 项存储到 QMap 中，但如何将子节点附加到父节点并将父节点附加到 rootNode？

代码。

standardModel = new QStandardItemModel(this);
QStandardItem *rootNode = standardModel->invisibleRootItem();
QSqlQuery *itemqry = new QSqlQuery("SELECT GroupCode, AcName, ActCod from adm_ac");
while(itemqry->next()){
    int groupcode =itemqry->value(0).toInt();
    QString acname = itemqry->value(1).toString();
    int ActCod = itemqry->value(2).toInt();
    QStandardItem *itemmap = new QStandardItem(acname);
    rowItemMap.insert(groupcode, itemmap);

    }
}
 ui->treeView->setModel(standardModel);

头文件。

QStandardItemModel *standardModel;
QStandardItem *acName1;
QStandardItem *acName2;
QMap<int, QStandardItem*> rowItemMap;

Answer 1

一种可能是将 ActCod 保存在一个角色中，然后使用 match() 方法通过 GroupCode 进行父级搜索：

#include <QtWidgets>
#include <QtSql>

static bool createConnection(){
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(":memory:");
    if (!db.open()) {
        qDebug()<<"Cannot open database\n"
                  "Unable to establish a database connection.\n"
                  "This example needs SQLite support. Please read "
                  "the Qt SQL driver documentation for information how "
                  "to build it.\n\n"
                  "Click Cancel to exit.";
        return false;
    }
    QSqlQuery query;
    if(!query.exec("CREATE TABLE adm_ac("
                   "AcName TEXT,"
                   "ActCod INTEGER,"
                   "GroupCode INTEGER"
                   ")"))
        qDebug()<<query.lastError().text();
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"parent1\", 1, 0)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"child1\", 101, 1)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"parent2\", 2, 0)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"child2\", 201, 2)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"A\", 10000, 101)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"B\", 10001, 201)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"C\", 100000, 10000)");
    query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"D\", 100001, 10001)");
    return true;
}

enum RelationRoles{
    CodeRole = Qt::UserRole + 1000,
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    if(!createConnection())
        return -1;
    QStandardItemModel model;
    QSqlQuery  query("SELECT GroupCode, AcName, ActCod from adm_ac");
    const QSqlRecord rec = query.record();
    while (query.next()) {
        QString AcName = query.value(rec.indexOf("AcName")).toString();
        int GroupCode = query.value(rec.indexOf("GroupCode")).toInt();
        int ActCod = query.value(rec.indexOf("ActCod")).toInt();
        QStandardItem *it = new QStandardItem(AcName);
        it->setData(ActCod, RelationRoles::CodeRole);
        if(GroupCode == 0)
            model.invisibleRootItem()->appendRow(it);
        else{
            QModelIndexList ixs = model.match(model.index(0, 0),
                                              RelationRoles::CodeRole,
                                              GroupCode,
                                              1,
                                              Qt::MatchExactly| Qt::MatchRecursive);
            if(ixs.size() > 0){
                QStandardItem *parent = model.itemFromIndex(ixs.first());
                parent->appendRow(it);
            }
        }
    }
    QTreeView w;
    w.setModel(&model);
    w.expandAll();
    w.show();
    return a.exec();
}

你的情况：

// ...
enum RelationRoles{
    CodeRole = Qt::UserRole + 1000,
};
// ...
standardModel = new QStandardItemModel(this);
QSqlQuery  query("SELECT GroupCode, AcName, ActCod from adm_ac");
const QSqlRecord rec = query.record();
while (query.next()) {
    QString AcName = query.value(rec.indexOf("AcName")).toString();
    int GroupCode = query.value(rec.indexOf("GroupCode")).toInt();
    int ActCod = query.value(rec.indexOf("ActCod")).toInt();
    QStandardItem *it = new QStandardItem(AcName);
    it->setData(ActCod, RelationRoles::CodeRole);
    if(GroupCode == 0)
        standardModel->invisibleRootItem()->appendRow(it);
    else{
        QModelIndexList ixs = standardModel->match(model.index(0, 0),
                                          RelationRoles::CodeRole,
                                          GroupCode,
                                          1,
                                          Qt::MatchExactly| Qt::MatchRecursive);
        if(ixs.size() > 0){
            QStandardItem *parent = standardModel->itemFromIndex(ixs.first());
            parent->appendRow(it);
        }
    }
}

ui->treeView->setModel(standardModel);

好处是不用像QMap那样自己创建容器，可以避免访问不允许的内存和元素重复的问题。

更新1：

// ...
QSqlQuery query;
if(!query.exec("CREATE TABLE adm_ac("
               "AcName TEXT,"
               "ActCod INTEGER,"
               "GroupCode INTEGER"
               ")"))
    qDebug()<<query.lastError().text();
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"EXPENSES\", 5, 0)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"SALES\", 4, 0)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ASSETS\", 1, 0)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"CAPITAL\", 3, 0)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"LIAILITIES\", 2, 0)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"CURRENT ASSETS\", 102, 1)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"FIXED ASSETS\", 101, 1)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"INTANGIBLE FIXED ASSETS\", 10102, 101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACCUM.DEP. FIXED ASSETS\", 10103, 101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"TANGIBLE FIXED ASSETS\", 10101, 101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"MACHINERY\", 1010102, 10101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"COMPUTERS\", 1010103, 10101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"LAND\", 1010101, 10101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"OFFICE EQUIPMENTS\", 1010104, 10101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"MOTOR VEHICLES\", 1010105, 10101)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"COMPUTER SOFTWARE\", 1010203, 10102)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"GOODWILL\", 10102001, 10102)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"PATENTS & TRADE MARKS\", 10102002, 10102)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACC.DEP- MOTOR VEHICLES\", 10103004, 10103)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACC.DEP- OFFICE EQUIPMENTS\", 10103003, 10103)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACC.DEP- MACHINERY\", 10103001, 10103)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACC.DEP- COMPUTERS\", 10103002, 10103)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"ACCOUNTS RECEIVABLE\", 10205, 102)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"STOCK\", 1010105, 102)");
query.exec("insert into adm_ac(AcName, ActCod, GroupCode) values(\"DEPOSITS & PREPAYMENTS\", 10212, 102)");
return true;
// ...

更新2：

我忘了在我的解决方案中假设数据是有序的，因为在我的算法中我认为父项在子项之前但在一般情况下它是不正确的，因此必须使用以下命令进行排序： ORDER BY ActCod ASC

QSqlQuery query("SELECT GroupCode, AcName, ActCod from adm_ac ORDER BY ActCod ASC");

Answer 2

这是构建树的另一种方法。此代码还注意子节点在其父节点之前加载的情况。树将分两次构建：

将所有项目加载到地图
根据地图构建树

编辑： 我们使用 setData() 函数而不是 setProperty，因为 QStardardItem 不是 QObject 派生的。

    enum GroupCodeRoleEnum{
        GroupCodeRole = Qt::UserRole + 1001,
    };

    while(itemqry->next())
    {
        int groupcode =itemqry->value(0).toInt();
        QString acname = itemqry->value(1).toString();
        int ActCod = itemqry->value(2).toInt();
        QStandardItem *itemmap = new QStandardItem(acname);

        itemMap->setData(groupcode, GroupCodeRole );

        //map of ActCod to itemmap, not GroupCode
        rowItemMap.insert(ActCod, itemmap) );

    } //End of while -- every node were now loaded.

    //build the tree
    rowItemMap.insert (0, rootNode ) ;

    foreach( QStandardItem * p, rowItemMap.values() ){
        int groupCode = p->data( GroupCodeRole ).toInt();

        //find the parent from the map
        if( p != rootNode ){

            QMap<int, QStandardItem* >::iterator it = rowItemMap.find( groupCode );

            if( it != rowItemMap.end() ){

                QStandardItem* pParent = it.value();
                pParent->appendRow( p );
            }else {
                qDebug() << "Parent not exist for groupCode" << groupCode; 
            }

        }//nomal node

    } //foreach  

    ui->treeView->setModel(standardModel);

测试代码：

        QStandardItemModel *standardModel = new QStandardItemModel(this);
        QStandardItem *rootNode = standardModel->invisibleRootItem();

        //Simulate your while() loop.
        addItem(1, 0, "parent 1");
        addItem(101, 1, "child 1");
        addItem(2, 0, "parent 2");
        addItem(201, 2, "child 2");

        //childs were loaded before parents

        addItem(301, 3, "child 3");
        addItem(401, 4, "child 4");
        addItem(501, 5, "child 5");

        addItem(3, 2, "parent 3");
        addItem(4, 2, "parent 4");
        addItem(5, 2, "parent 5");

        //build the tree
        m_map.insert (0, rootNode ) ;

        foreach( QStandardItem * p, m_map.values() ){
            int groupCode = p->data( GroupCodeRole ).toInt();

            //find the parent from the map
            if( p != rootNode ){

                QMap<int, QStandardItem* >::iterator it = m_map.find( groupCode );

                if( it != m_map.end() ){

                    QStandardItem* pParent = it.value();
                    pParent->appendRow( p );
                }else {
                    qDebug() << "Parent not exist for groupCode" << groupCode;
                }

            }//nomal node

        } //foreach

        ui->treeView->setModel(standardModel);
    }

    void MainWindow::addItem(int Act, int nGroupCode, QString szName)
    {
            QStandardItem *itemmap = new QStandardItem( szName );

            itemmap->setData(nGroupCode, GroupCodeRole );

            //map of ActCod to itemmap, not GroupCode
            m_map.insert(Act, itemmap);

    }

树已建成：

从数据库中填充 QTreeView 作为父节点和子节点

Populate QTreeView as parent and child nodes from database

c++

qt

qtreeview

qstandarditemmodel

qt5