ObjectModel:Qml 使用C++model

用QList<QObject*> 来实现model
官方为何叫做ObjectModel
打比方有一个QObject*   obj ;
Q_INVOKABLE  QVariant _get()
{
QObject*  obj = xxx;
Variant::fromValue(obj );
}
Qml调用它打印返回值:ObjectModel..

ObjectModel是把QObject对象当做model的每一项,优势是访问方便扩展强,劣势是要手动删除指针,避免内存泄漏,并且需要自己刷新model(每次数据变化视图不会改变,要在代码中重新赋值)

#ifndef OBJECTMODEL_H
#define OBJECTMODEL_H

#include <QObject>
#include<QDEBUG>
class ObjectModel : public QObject
{
Q_OBJECT
Q_PROPERTY(QString data READ get WRITE set  NOTIFY dataChanged)

public:
explicit ObjectModel(QObject *parent = 0);
~ObjectModel() {
}
void set(QString s)
{
data = s;
}
QString get()
{
return data;
}

signals:
void  dataChanged(QString data);
public slots:
private:
QString  data;
};

#endif // OBJECTMODEL_H

#ifndef QMLGLOBALDATA_H
#define QMLGLOBALDATA_H

#include<QtCore/QObject>
#include<map>
#include<QtCore/QVariant>
#include<qmlglobalsetting.h>
#include "objectmodel.h"
using namespace  std;
class QmlGlobalData : public QObject
{
Q_OBJECT
public:

explicit QmlGlobalData(QObject *parent = 0);
~QmlGlobalData();
//获取
Q_INVOKABLE  QVariant _objmodel()
{
return QVariant::fromValue(objmodellist);
}
//添加
Q_INVOKABLE  QVariant _objmodel_add(QString var1)
{
ObjectModel*  j;
(j = new ObjectModel())->set(var1);
objmodellist.append(j);
return QVariant::fromValue(objmodellist);
}
//清空
Q_INVOKABLE  void _objmodel_cls()
{
for (int x = 0; x < objmodellist.count(); x++)
{
/*qDebug() << "delete";*/
delete   objmodellist.at(x);
}
objmodellist.clear();

}
//得到大小
Q_INVOKABLE  int _objmodel_size()
{
return objmodellist.count();

}

//获取
Q_INVOKABLE  QVariant _objmodel_get(int index)
{
QObject*  obj = objmodellist.at(index);
return QVariant::fromValue(obj);
}
//删除
Q_INVOKABLE  QVariant _objmodel_delete(int index)
{
if (index < 0  || index >= objmodellist.count())
{
return  QVariant::fromValue(objmodellist);
}
QObject*  obj = objmodellist.at(index);
if (obj!=NULL)
{
delete obj;
objmodellist.removeAt(index);
}
return QVariant::fromValue(objmodellist);
}

signals:

public slots:
private:
QList<QObject*>  objmodellist;
};

int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);

QQmlApplicationEngine engine;
// 首先注册一下类 为了触发语法高亮
qmlRegisterType<QmlGlobalData>(
"Global",
1,
0,
"Global");
QmlGlobalData*  tmp = new QmlGlobalData();
engine.rootContext()->setContextProperty("Global", tmp);
engine.load(QUrl(QLatin1String("qrc:/main.qml")));

return app.exec();
}

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.0
ApplicationWindow {
visible: true
width: 640
height: 480
title: qsTr("Hello World")

property var xx: 0
Flickable{
width: parent.width
height: parent.height
contentHeight: col.height

Column{

id:col
ListView{
id:list
width: parent.width
height: contentHeight
delegate: Text{
text:model.modelData.data
//Global._objmodel_get(index).data
}
Component.onCompleted: {

}

}

Button{
text:"添加"
onClicked: {
append(xx)
}
}

Button{
text:"清空"
onClicked: {
clear()
}
}

Button{
text:"遍历"
onClicked: {
_Enumdata()
}
}

Row{
Button{
text:"删除第x行:"
onClicked: {
removeAt(_index.text)
}
}

TextField{id:_index}
}
}

}

function append(var1)
{
list.model= Global._objmodel_add(var1);
xx++;
}

function  clear()
{
list.model= Global._objmodel_cls();
}

function _Enumdata()
{
var _size =  Global._objmodel_size();
for(var i=0;i<_size;i++)
{
console.log("get:"+i+","+Global._objmodel_get(i).data)
}
}

function  removeAt(index)
{
list.model=Global._objmodel_delete(index)
}

}