我尝试从C ++将QML地图项(例如MapQuickItem或MapCircle)添加到我的地图。不幸的是,它们没有出现在地图上。只有QML矩形的相同代码有效。rect v1是用于测试的矩形。 rect v2是无法使用的mapCircle。当我将地图圈QML代码1:1添加到地图QML代码中时,效果很好。
main.cpp:
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQuickView *view = new QQuickView;
view->setSource(QUrl("qrc:/map.qml"));
QQmlComponent compRect (view->engine(), QUrl("qrc:/rect.qml"));
view->setWidth(1000);
view->setHeight(650);
view->setTitle("GUI");
QQuickItem *map = view->findChild<QQuickItem*>("map1");
QQuickItem *rect = qobject_cast<QQuickItem*>(compRect.create(view->rootContext()));
rect->setParentItem(map);
rect->setParent(map); //know this is not for visual objects, just for test
view->show();
return app.exec();
}
rect.qml v1
import QtQuick 2.14
import QtLocation 5.14
import QtPositioning 5.14
Rectangle
{
color: "grey"
opacity: .8
width: 100
height: 100
radius: 4
Text
{
id: text
anchors.centerIn: parent
text: "hi"
color: "orangered"
font.weight: Font.Bold
}
}
rect.qml v2
import QtQuick 2.14
import QtLocation 5.14
import QtPositioning 5.14
MapCircle
{
center
{
latitude: 47.5
longitude: 8.9
}
radius: 5000.0
color: 'green'
border.width: 3
}
map.qml
import QtQuick 2.12
import QtQuick.Window 2.12
import QtPositioning 5.14
import QtLocation 5.14
Map
{
objectName: "map1"
id: map_map
anchors.centerIn: parent;
anchors.fill: parent
plugin: Plugin
{
name: "mapboxgl" // "osm", "esri", ...
}
center: QtPositioning.coordinate(47.6,9.5)
zoomLevel: 8
// get position of device and set map center to it
PositionSource
{
active: true
onPositionChanged:
{
map.center(position.coordinate)
console.log(position.coordinate)
}
}
Timer
{
id: timerReload
interval: 1000
repeat: true
running: true
onTriggered:
{
controller.triggerReload();
}
}
}
确定项目是地图的子项并不意味着它会显示在地图上,如果要添加项目,则必须使用addMapItem()
方法,在C ++中,可以使用addMapItem()
调用该方法,但是您需要访问属于私有Qt API的类型QMetaObject::invokeMethod()
,考虑到上述解决方案是:
*。pro
QMetaObject::invokeMethod()
main.cpp
QDeclarativeGeoMapItemBase
先前方法的问题是危险的,因为可以随时删除地图或任何QML元素,从而可能产生问题,此外它还限制了QML的修改,最后有必要访问私有Qt API可以更改,恕不另行通知。因此,我将提供更好的选择:
使用QObject并将其导出到创建项目并将其添加到地图的QML:
QT += quick location location-private
CONFIG += c++11
DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += main.cpp
RESOURCES += qml.qrc
#include <QGuiApplication>
#include <QQuickItem>
#include <QQuickView>
#include <QtLocation/private/qdeclarativegeomapitembase_p.h>
int main(int argc, char *argv[]){
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQuickView view;
view.setSource(QUrl("qrc:/map.qml"));
view.resize(1000, 650);
view.setTitle("GUI");
view.show();
if(QQuickItem *map = view.findChild<QQuickItem*>("map1")){
QQmlComponent component(view.engine(), QUrl("qrc:/rect.qml"));
if(QDeclarativeGeoMapItemBase *rect = qobject_cast<QDeclarativeGeoMapItemBase*>(component.create(view.rootContext()))){
bool status = QMetaObject::invokeMethod(map,
"addMapItem",
Qt::DirectConnection,
Q_ARG(QDeclarativeGeoMapItemBase*, rect));
Q_ASSERT(status);
}
}
return app.exec();
}
或
#include <QGuiApplication>
#include <QQuickView>
#include <QGeoCoordinate>
#include <QQmlContext>
class Helper: public QObject{
Q_OBJECT
public:
void addCircle(const QGeoCoordinate & coordinate){
Q_EMIT circleSignal(coordinate);
}
Q_SIGNALS:
void circleSignal(const QGeoCoordinate & coordinate);
};
int main(int argc, char *argv[]){
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQuickView view;
Helper helper;
view.rootContext()->setContextProperty("helper", &helper);
view.setSource(QUrl("qrc:/map.qml"));
view.resize(1000, 650);
view.setTitle("GUI");
view.show();
helper.addCircle(QGeoCoordinate(47.6, 9.5));
return app.exec();
}
#include "main.moc"
将模型与MapItemView一起使用:
import QtQuick 2.14
import QtPositioning 5.14
import QtLocation 5.14
Map{
id: map_map
anchors.centerIn: parent;
anchors.fill: parent
plugin: Plugin {
name: "mapboxgl" // "osm", "esri", ...
}
center: QtPositioning.coordinate(47.6,9.5)
zoomLevel: 8
Connections{
target: helper
onCircleSignal: {
var component = Qt.createComponent("rect.qml");
if (component.status === Component.Ready){
var o = component.createObject(map_map);
o.center = coordinate
map_map.addMapItem(o)
}
}
}
}
import QtQuick 2.14
import QtPositioning 5.14
import QtLocation 5.14
Map{
id: map_map
anchors.centerIn: parent;
anchors.fill: parent
plugin: Plugin {
name: "mapboxgl" // "osm", "esri", ...
}
center: QtPositioning.coordinate(47.6,9.5)
zoomLevel: 8
Component{
id: provider
MapCircle{
center{
latitude: 47.6
longitude: 9.5
}
radius: 5000.0
color: 'green'
border.width: 3
}
}
function createCirle(map, position){
var o = provider.createObject(map)
o.center = position
map.addMapItem(o)
return o
}
Connections{
target: helper
onCircleSignal: {
var o = createCirle(map_map, coordinate)
}
}
}