问题描述
map.qml:
import QtQuick 2.10
import QtQuick.Controls 2.3
import QtLocation 5.6
import QtPositioning 5.6
Rectangle {
ListModel {
id: locationModel
}
Plugin {
id: mapPlugin
name: "esri"
}
Map {
id: place
anchors.fill: parent
plugin: mapPlugin
center: QtPositioning.coordinate(51.5,0.1)
zoomLevel: 7
MapItemView
{
model: locationModel
delegate: mapcomponent
}
}
Component {
id: mapcomponent
MapQuickItem {
id: marker
anchorPoint.x: image.width/2
anchorPoint.y: image.height/2
coordinate: QtPositioning.coordinate(lat,lon)
sourceItem: Image {
id: image
width: 100
height: 50
source: "qrc:/rec/marker.png"
}
}
}
function addplace(lat: double,lon: double){
locationModel.append({"lat": lat,"lon": lon})
console.log("Done")
}
}
mainwindow.cpp:
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->quickWidget->setSource(QUrl("qrc:/rec/map.qml"));
QQmlComponent component(ui->quickWidget->engine(),ui->quickWidget->source());
object = component.create();
}
/*Some not interesting code.*/
void MainWindow::on_pushButton_4_clicked()
{
double lat = 50.00;
double lon = 20.00;
QMetaObject::invokeMethod(object,"addDevice",Q_ARG(double,lat),lon));
}
object
在 mainwindow.h 中定义如下:QObject *object;
。
当单击某个按钮时,会从 c ++ 文件调用 add place
函数。不幸的是,由于某种原因,此功能无法正常工作。调用之后,控制台会出现“完成”的消息,并且在地图上要标记的点的位置被添加到ListModel中。不幸的是,标记没有出现在地图上。我究竟做错了什么?如有任何建议,我将不胜感激。
解决方法
问题在于您正在使用新地图创建新组件,并将标记添加到新的不可见地图。
与其将 QML 对象暴露给 C++,不如做相反的事情:
#ifndef PLACEHELPER_H
#define PLACEHELPER_H
#include <QObject>
class PlaceHelper : public QObject
{
Q_OBJECT
public:
explicit PlaceHelper(QObject *parent = nullptr);
void addPlace(double latitude,double longitude);
Q_SIGNALS:
void add(double latitude,double longitude);
};
#endif // PLACEHELPER_H
#include "placehelper.h"
PlaceHelper::PlaceHelper(QObject *parent) : QObject(parent)
{
}
void PlaceHelper::addPlace(double latitude,double longitude)
{
Q_EMIT add(latitude,longitude);
}
*.h
// ..
private:
Ui::MainWindow *ui;
PlaceHelper placeHelper;
};
*.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QQmlContext>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->quickWidget->rootContext()->setContextProperty("placeHelper",&placeHelper);
ui->quickWidget->setSource(QUrl("qrc:/rec/map.qml"));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_4_clicked()
{
double lat = 50.00;
double lon = 0.10;
placeHelper.addPlace(lat,lon);
}
import QtQuick 2.10
import QtQuick.Controls 2.3
import QtLocation 5.6
import QtPositioning 5.6
Rectangle {
ListModel {
id: locationModel
}
Plugin {
id: mapPlugin
name: "esri"
}
Map {
id: place
anchors.fill: parent
plugin: mapPlugin
center: QtPositioning.coordinate(51.5,0.1)
zoomLevel: 7
MapItemView
{
model: locationModel
delegate: mapcomponent
}
}
Component {
id: mapcomponent
MapQuickItem {
id: marker
anchorPoint.x: image.width/2
anchorPoint.y: image.height/2
coordinate: QtPositioning.coordinate(lat,lon)
sourceItem: Image {
id: image
width: 100
height: 50
source: "qrc:/rec/marker.png"
}
}
}
Connections{
target: placeHelper
function onAdd(latitude,longitude){
locationModel.append({"lat": latitude,"lon": longitude})
}
}
}
另一种解决方案是将模型用 C++ 实现并导出到 QML:
#ifndef PLACEMODEL_H
#define PLACEMODEL_H
#include <QStandardItemModel>
class PlaceModel: public QStandardItemModel
{
Q_OBJECT
public:
enum PlaceRoles {
LatitudeRole = Qt::UserRole + 1,LongitudeRole
};
PlaceModel(QObject *parent=nullptr);
Q_INVOKABLE void addPlace(double longitude,double latitude);
};
#endif // PLACEMODEL_H
#include "placemodel.h"
PlaceModel::PlaceModel(QObject *parent):
QStandardItemModel(parent)
{
setItemRoleNames({{LatitudeRole,"lat"},{LongitudeRole,"lon"}});
}
void PlaceModel::addPlace(double latitude,double longitude)
{
QStandardItem *item = new QStandardItem;
item->setData(latitude,LatitudeRole);
item->setData(longitude,LongitudeRole);
appendRow(item);
}
*.h
private:
Ui::MainWindow *ui;
PlaceModel placeModel;
*.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QQmlContext>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->quickWidget->rootContext()->setContextProperty("placeModel",&placeModel);
ui->quickWidget->setSource(QUrl("qrc:/rec/map.qml"));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_4_clicked()
{
double lat = 50.00;
double lon = 0.10;
placeModel.addPlace(lat,lon);
}
import QtQuick 2.10
import QtQuick.Controls 2.3
import QtLocation 5.6
import QtPositioning 5.6
Rectangle {
Plugin {
id: mapPlugin
name: "esri"
}
Map {
id: place
anchors.fill: parent
plugin: mapPlugin
center: QtPositioning.coordinate(51.5,0.1)
zoomLevel: 7
MapItemView
{
id: mapView
model: placeModel
delegate: mapcomponent
}
}
Component {
id: mapcomponent
MapQuickItem {
id: marker
anchorPoint.x: image.width/2
anchorPoint.y: image.height/2
coordinate: QtPositioning.coordinate(lat,lon)
sourceItem: Image {
id: image
width: 100
height: 50
source: "qrc:/rec/marker.png"
}
}
}
}