Qt小例子学习90 - 从txt读出gps数据显示
main.qml
import QtQuick 2.12
import QtQuick.Window 2.12import QtLocation 5.12
import QtPositioning 5.12Window {visible: truewidth: 640height: 480title: qsTr("Hello World")Plugin {id: mapPluginname: "osm"}Map {id: mapanchors.fill: parentplugin: mapPlugincenter: QtPositioning.coordinate(14.70202102, 121.0957246)zoomLevel: 15MapQuickItem{id: markeranchorPoint.x: marker.width / 4anchorPoint.y: marker.heightcoordinate: manager.positionsourceItem: Image { source: "qrc:/marker.png"Text { text: "Location" ; font.pointSize: 8; font.bold: true }}}}
}main.cpp
#include <QFile>
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QTextStream>
#include <QTimer>
#include <QGeoCoordinate>
#include <QRegularExpression>class MarkerManager: public QObject
{Q_OBJECTQ_PROPERTY(QGeoCoordinate position READ position NOTIFY positionChanged)
public:MarkerManager(QObject *parent = nullptr): QObject(parent){connect(&timer, &QTimer::timeout, this, &MarkerManager::readLine);}bool loadFile(const QString &filename, int interval = 100){file.setFileName(filename);if (!file.open(QIODevice::ReadOnly | QIODevice::Text))return false;ts.setDevice(&file);timer.start(interval);return true;}QGeoCoordinate position() const{return m_position;}
Q_SIGNALS:void positionChanged();
private Q_SLOTS:void readLine(){if (!ts.atEnd()){QString line = ts.readLine();QStringList elements = line.split(QRegularExpression("\\s+"));if (elements.count() == 2){bool ok1, ok2;double lat = elements[0].toDouble(&ok1);double lng = elements[1].toDouble(&ok2);if (ok1 && ok2){m_position = QGeoCoordinate(lat, lng);Q_EMIT positionChanged();}}}}
private:QFile file;QTextStream ts;QTimer timer;QGeoCoordinate m_position;
};#include "main.moc"int main(int argc, char *argv[])
{QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);QGuiApplication app(argc, argv);MarkerManager manager;manager.loadFile("data_gps.txt");QQmlApplicationEngine engine;engine.rootContext()->setContextProperty("manager", &manager);const QUrl url(QStringLiteral("qrc:/main.qml"));QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,&app, [url](QObject * obj, const QUrl & objUrl){if (!obj && url == objUrl)QCoreApplication::exit(-1);}, Qt::QueuedConnection);engine.load(url);return app.exec();
}