QML与C++交互:在qml中使用QSqlQueryModel显示数据库数据

本文博客链接:,作者:jdh,转载请注明.

參考链接:

环境：

主机:WIN7

开发环境:Qt5.2.1

说明:

在QML中不能直接对数据库进行操作,所以将QSqlQueryModel封装成子类,作为属性给QML使用

效果图:

源码:

qml文件里负责数据托管显示的代码:

Component        {            id: msnDelegate            Item            {                id: wrapper                width: grid.cellWidth; height: grid.cellHeight                Column                {                    Image{ source: "pics/light_on.png";anchors.horizontalCenter: parent.horizontalCenter; width: grid.cellWidth * 0.7; height: grid.cellHeight * 0.7}                    Text { text: ctrl_id;anchors.horizontalCenter: parent.horizontalCenter; color: wrapper.GridView.isCurrentItem ?

"red" :"blue" } Text { text: name;anchors.horizontalCenter: parent.horizontalCenter; color: wrapper.GridView.isCurrentItem ? "red" :"blue" } } MouseArea { anchors.fill: parent onClicked: grid.currentIndex = index } } } GridView { id:grid //anchors.fill: parent width: parent.width height: parent.height - space1.height anchors {top: space1.bottom;} cellWidth: parent.width * 0.25 cellHeight: parent.width * 0.25 //model: listModel model: myFirstModel delegate: msnDelegate highlight: Rectangle { color: "lightsteelblue"; radius: 5 } currentIndex: 2 //focus: true }

C++代码:

sqlquerymodel.h

#ifndef SQLQUERYMODEL_H#define SQLQUERYMODEL_H#include 
     
      class SqlQueryModel : public QSqlQueryModel{    Q_OBJECT    void generateRoleNames();public:    explicit SqlQueryModel(QObject *parent = 0);    void setQuery(const QString &query, const QSqlDatabase &db = QSqlDatabase());    void setQuery(const QSqlQuery &query);    QVariant data(const QModelIndex &index, int role) const;    virtual QHash
      
        roleNames() const;signals:public slots:};#endif // SQLQUERYMODEL_H
      
     

sqlquerymodel.cpp

#include "sqlquerymodel.h"#include 
     
      #include 
      
       #include 
       
        SqlQueryModel::SqlQueryModel(QObject *parent) :    QSqlQueryModel(parent){}void SqlQueryModel::setQuery(const QString &query, const QSqlDatabase &db){    QSqlQueryModel::setQuery(query,db);    generateRoleNames();}void SqlQueryModel::setQuery(const QSqlQuery & query){    QSqlQueryModel::setQuery(query);    generateRoleNames();}void SqlQueryModel::generateRoleNames(){    QHash
        
          roleNames;    for( int i = 0; i < record().count(); i++) {        roleNames[Qt::UserRole + i + 1] = record().fieldName(i).toUtf8();    }    //setRoleNames(roleNames);}QHash
         
           SqlQueryModel::roleNames() const{    QHash
          
            roleNames; for( int i = 0; i < record().count(); i++) { roleNames[Qt::UserRole + i + 1] = record().fieldName(i).toUtf8(); } return roleNames;}QVariant SqlQueryModel::data(const QModelIndex &index, int role) const{ QVariant value = QSqlQueryModel::data(index, role); if(role < Qt::UserRole) { value = QSqlQueryModel::data(index, role); } else { int columnIdx = role - Qt::UserRole - 1; QModelIndex modelIndex = this->index(index.row(), columnIdx); value = QSqlQueryModel::data(modelIndex, Qt::DisplayRole); } return value;}
          
         
        
       
      
     

主函数中

数据关联的代码:

SqlQueryModel *model1 = new SqlQueryModel(0);    model1->setQuery("SELECT * FROM ctrl_para");    QtQuick2ApplicationViewer viewer;    viewer.rootContext()->setContextProperty("myFirstModel", model1);    viewer.setMainQmlFile(QStringLiteral("qml/SH_User/base.qml"));    viewer.showExpanded();

注意:

query操作仅仅运行一次,所以要想实时显示数据库中的数据,能够定时读取数据库以动态显示数据