I'm trying to load a mapbox in my c++/qt application. On my PC the application is working fine, and the map is loaded. However, when the
application is deployed on the raspberry(v3) the application is running but the map is not loaded(a blank screen appears).
I've tried a different map plugins such as esri and they work fine
on the raspberry. But the mapbox plugin wont work
Here is the code I'm working on
import QtQuick 2.0
import QtQuick.Window 2.0
import QtLocation 5.6
import QtPositioning 5.6
Window {
width: 512
height: 512
visible: true
Plugin {
id: mapPlugin
name: "mapboxgl" // "mapboxgl", "esri", ...
// specify plugin parameters if necessary
// PluginParameter {
// name:
// value:
// }
}
Map {
anchors.fill: parent
plugin: mapPlugin
center: QtPositioning.coordinate(41.38, 2.16) // Oslo
zoomLevel: 14
}
}
And the C++ code
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
I'm expecting a mapbox type map to be loaded but only a blank screen appears. There are no any error messages.
I think it's because a plugin is missing or something. But then why it is working on my laptop since I have the same version of QT in both machines: (QT 5.10)
Related
I'm trying to implement a tumbler to set the time for an alarm in C++. Yet I've only seen tumblers in Qt quick and therefore coded in QML. Now I've tried to get QML code in my C++ code by doing:
void SmartAlarm::showTumbler(){
// Create the QML view
QQuickView* quickView = new QQuickView(QUrl(":/files/includes/AlarmTumbler.qml"));
// Make the QML view resize when the parent is resized
quickView->setResizeMode(QQuickView::SizeRootObjectToView);
QWidget* quickWidget = QWidget::createWindowContainer(quickView);
rightLayout->addWidget(quickWidget);
}
My QML file looks like this:
import QtQuick 2.12
import QtQuick.Window 2.2
import QtQuick.Controls 2.12
import QtQuick.Extras 1.4
TumblerColumn{
id: weekdayTumbler
model: ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
}
TumblerColumn {
id: hourTumbler
model: 24
}
TumblerColumn {
id: minuteTumbler
model: 60
}
All I get is a blank, white widget in my layout. What am I doing wrong? Is there a way to implement a tumbler in Qt without using QMLs?
I think it doesn't find the tumbler-file. You can check this the easiest by starting the program and check in the Application Output (Bottom Menu in QTCreator) for following message:
":/files/includes/AlarmTumbler.qml: No such file or directory"
If you can't find it, it might be because you use a Shadow Build and the actual execution-files are in a different folder than the QML Files. To solve this, you can go to "Projects" and deactivate "Shadow Build", rebuild and you should see the tumbler.
The implementation itself should work fine. I tested it locally, added everything to the MainWindow though cause I don't know where your "rightLayout" comes from.
ui->setupUi(this);
// Create the QML view
QQuickView* quickView = new QQuickView(QUrl("tumbler.qml"));
// Make the QML view resize when the parent is resized
quickView->setResizeMode(QQuickView::SizeRootObjectToView);
QWidget* quickWidget = QWidget::createWindowContainer(quickView);
this->ui->rightLayout->addWidget(quickWidget);
I'm trying to build a super simple dummy web-view with Qt and WebKit to view pages, so that I can better understand the WebKit2 split process model.
Existing examples/questions (like Example code for a simple web page browser using WebKit QT in C++) seem to use the "old" style WebKit, in which rendering and displaying are done in one process. What is the equivalent of that example but done for WebKit2?
Is it so difficult with WebKit2 that there aren't any basic examples out there?
Qt's WebKit2 is available only for QML.
With Qt 5 and Webkit2 the APIs for QtWebKit and Web View are changing significantly. This is because with WebKit2, WebKit and the application run in different processes. The old QWebView widget will only be supported on Qt for desktops and won't use the new WebKit2. Mobile phone platforms typically won't have the QWidgets module installed in Qt 5.
Examples which uses QtWebKit QML API that utilizes the WebKit2 split-process architecture could be found in Qt WebKit documentation There is Flickr View and YouTube View examples
Qt also has WebView module with examples like Minibrowser
And WebEngine module. Examples can be found here
And here is a simplest WebKit2 example which just shows google webpage
Use Qt 5.5.1 to run this example.
Add following to your .pro file: QT += quick qml webkit
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
if (engine.rootObjects().isEmpty())return -1;
return app.exec();
}
main.qml
import QtQuick 2.0
import QtQuick.Window 2.0
import QtWebKit 3.0
Window {
visible: true
width: 967
height: 480
WebView {
id: webView
anchors.fill: parent
opacity: 0
url: "https://google.com"
Behavior on opacity
{
NumberAnimation { duration: 200 }
}
onLoadingChanged:
{
switch (loadRequest.status)
{
case WebView.LoadSucceededStatus:
opacity = 1
break
default:
opacity = 0
break
}
}
onNavigationRequested:
{
request.action = WebView.AcceptRequest
}
}
}
I am developing a user interface with qt/QML and I need to show a splashscreen image at the begininning of the application.
I'm running the application on a device with a iMX6 microprocessor.
I used the library QtSplashscreen but it gives me this error: EGLFS: openGL windows cannot be mixed with others.
I know that it cannot open 2 windows simultaneously, can somebody help?
About your problem, see this question:
OpenGL and Qt Quick 2 applications can only have one fullscreen window existing at a time. Trying to create another OpenGL window, or trying to mix an OpenGL window with a raster one will display the above message and abort the application.
QSplashScreen use another window to show the splash view. So, this is not a direct solution. You can embed your QWidget inside a QQuickItem to use it as QtQuick2 control components.
Another, and faster solution is to use a QML component and load it with a Loader. You can take a look in the Qt Examples Repository, this file is a good example.
Here we go with an easy example;
Loader {
id: splashLoader
anchors.fill: parent
source: "SplashScreen.qml"
asynchronous: false
visible: true
onStatusChanged: {
if (status === Loader.Ready) {
appLoader.setSource("App.qml");
}
}
}
Connections {
target: splashLoader.item
onReadyToGo: {
appLoader.visible = true
appLoader.item.init()
splashLoader.visible = false
splashLoader.setSource("")
appLoader.item.forceActiveFocus();
}
}
Loader {
id: appLoader
anchors.fill: parent
visible: false
asynchronous: true
onStatusChanged: {
if (status === Loader.Ready)
splashLoader.item.appReady()
if (status === Loader.Error)
splashLoader.item.errorInLoadingApp();
}
}
In Qt's QML language for writing GUI code, QML elements are (if I understand correctly) not actually created until they become visible. (EDIT: It sounds like the elements are created when the QML engine loads them, but it appears that signal/slot connections are not made unless the elements are visible.)
I have some QML elements (LineSeries objects from QtCharts) that record some data over time, and I would like them to start recording data as soon as my app starts up, even though the ChartView elements containing each series aren't immediately visible (users must navigate to a page containing these elements).
Is this possible?
One approach might be to keep each data series itself in some kind of QVariantList containing QPointFs in a global QML object, then dynamically assign it to the desired LineSeries object when the parent ChartView is instantiated. This might be possible using ChartView::createSeries, though I believe the only way to populate the new series would be to call ChartView::series() and pass that to some kind of Q_INVOKABLE method in my C++ backend that would populate the series.
EDIT: Not sure if this is relevant, but the GUI element I'm using for navigation (i.e. the reason the ChartView isn't visible on startup) is a TabView. The ChartView objects are not top-level TabView pages; they're a couple levels down.
EDIT 2: The answer below seems like it should work, but I get the rather unhelpful error TypeError: Type error when I try to implement it. I've put together a minimal (non-)working example here (use qmlscene to run it; I am using Qt 5.5).
EDIT 3: The above non-working version was fixed by simply adding a property alias, thanks to Mitch's answer and comments.
Items in Qt Quick are created as soon as the QML they reside in is loaded by the QML engine (even if they default to non-visible). The exception to this rule are items that dynamically load their content, like Loader.
In your edit, you said that you're using TabView. I think that the setup you have is something like this:
import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.2
ApplicationWindow {
title: qsTr("Hello World")
width: 800
height: 700
visible: true
TabView {
id: sv
anchors.fill: parent
Tab {
title: "Page 1"
}
Tab {
title: "Page 2"
ChartView {}
}
}
}
Try changing it to something like this:
import QtQuick 2.4
import QtQuick.Controls 1.3
import QtQuick.Window 2.2
ApplicationWindow {
title: qsTr("Hello World")
width: 800
height: 700
visible: true
ChartView {
id: chartView
color: "red"
anchors.fill: parent
visible: false
Component.onCompleted: print("Monitoring data...")
}
TabView {
id: sv
anchors.fill: parent
Tab {
id: tab1
title: "Page 1"
}
Tab {
id: tab2
title: "Page 2"
onActiveChanged: {
if (active) {
chartView.parent = tab2;
chartView.visible = true;
}
}
}
}
}
Tabs are basically just Loaders, so they have all of Loader's API, including the active property. This property lets you know when that tab has been loaded. Before that stage, it's inaccessible.
When the tab becomes active, we reparent the ChartView to it so that it's displayed in the correct place, and then show it.
As you can see from the debug output, the ChartView is created at startup. You can move it somewhere else to control when it's loaded, or... use a Loader. :)
EDIT: Based on this answer and the discussion in the comments, OP has created a small working example that demonstrates how persistent items can be pre-loaded and re-parented.
I'm working on a OneDrive client for Linux built with Qt 5.3 + QtQuick UI controls. The issue I'm having is that MenuItem controls, after being activated, only draw fully every few attempts. Basically, clicking "File" in the Menu either produces a MenuItem called "Exit" or it shows up completely blank (white background, no text, no functionality). The issue shows itself very inconsistently. Sometimes it will do it 90% of the time or other times it will only show up 10-20% but in either case it's noticeable and annoying.
The whole project repository can be found at https://github.com/01000101/onedrive-linux-client/ but I've pasted one of the sections that has this issue. I'm using Qt Creator if that provides any hints. Dynamically generated menus (such as the one I also use for a right-click context menu) also is plagued by this.
Platform: Ubuntu 14.04 x86_64
Kernel: 3.13.0-34-generic
GCC: 4.8.2-19ubuntu1
import QtQuick 2.2
import QtQuick.Controls 1.2
import QtQuick.Dialogs 1.1
import QtQuick.Controls.Styles 1.2
ApplicationWindow {
id: page_auth
visible: true
width: 720
height: 480
color: "#343434"
title: qsTr("OneDrive Linux Client")
menuBar: MenuBar {
Menu {
title: qsTr("File")
MenuItem {
text: qsTr("Exit")
onTriggered: Qt.quit();
}
}
Menu {
title: qsTr("Help")
MenuItem {
text: qsTr("About")
onTriggered: messageDialog.open()
}
}
}
This is a bug in Qt. We have the same problem in our software. You can do nothing about it but wait.