Question

我的数据存储在数据库的以下列中

|AcName|ActCod|GroupCode|

|parent1| |1|   |0|

|child1|  |101| |1|

|parent2| |2|   |0|

|child2|  |201| |2|

我正在使用QTreeView，QStandardItemModel和QStandardItem创建此树形视图，但是我不知道如何将孩子附加到父亲。我将QStandardItem项存储到QMap中，但是如何将子节点附加到父节点，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

这里是构建树的另一种方法。该代码还注意子节点在其父节点之前加载的情况。该树将通过两次构建：

将所有项目加载到地图上
从地图上构建树

编辑：我们使用setData（）函数代替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：

Answer 2

一种可能的方法是将ActCod保存为一个角色，然后使用GroupCode方法通过match()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();
}

在您的情况下：

// ...
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);

优点是我们不必创建类似QMap的容器，因此可以避免访问不允许的内存以及元素重复的问题。

UPDATE1：

// ...
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;
// ...

UPDATE2：

我忘了提一下，在我的解决方案中，我假定数据是有序的，因为在我的算法中，我认为父级在子级之前，但是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：{{ 1}}

ORDER BY ActCod ASC

从数据库填充QTreeView作为父节点和子节点

2 个答案: