c++ - 将 QTreeView 填充为数据库中的父节点和子节点
问题描述
我将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
创建此树视图,但是我不知道如何将子项附加到父项。我将QStandardItem
项目存储到 aQMap
但如何将子节点附加到父节点和父节点rootNode
?
编码。
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;
解决方案
一种可能是将角色保存在角色中,然后使用以下方法ActCod
进行父搜索:GroupCode
match()
#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();
}
在你的情况下:
// ...
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像 QMap 这样的容器,因此我们可以避免访问不允许的内存以及元素重复的问题。
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:
我忘了提到,在我的解决方案中,我假设数据是有序的,因为在我的算法中,我认为父级在子级之前,但在一般情况下它是不正确的,因此必须使用以下命令对其进行排序:ORDER BY ActCod ASC
QSqlQuery query("SELECT GroupCode, AcName, ActCod from adm_ac ORDER BY ActCod ASC");
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