Qwidget plugin

hjohn

widgetplugin.cpp

#include "widgetplugins.h"
#include<QtPlugin>


void widgetPlugins::initialize(QDesignerFormEditorInterface *core)
{
    if (initialized)
        return;

    initialized = true;
}
widgetPlugins::widgetPlugins(QObject *parent)
    : QObject(parent)
{
}

bool widgetPlugins::isInitialized() const
{
    return initialized;
}

QWidget *widgetPlugins::createWidget(QWidget *parent)
{
    return new MainWindow(parent);
}

QString widgetPlugins::name() const
{
    return QStringLiteral("AnalogClock");
}

QString widgetPlugins::group() const
{
    return QStringLiteral("Display Widgets [Examples]");
}

QIcon widgetPlugins::icon() const
{
    return QIcon();
}

QString widgetPlugins::toolTip() const
{
    return QString();
}

QString widgetPlugins::whatsThis() const
{
    return QString();
}

bool widgetPlugins::isContainer() const
{
    return false;
}

QString widgetPlugins::domXml() const
{
    return "<ui language=\"c++\">\n"
           " <widget class=\"AnalogClock\" name=\"analogClock\">\n"
           "  <property name=\"geometry\">\n"
           "   <rect>\n"
           "    <x>0</x>\n"
           "    <y>0</y>\n"
           "    <width>100</width>\n"
           "    <height>100</height>\n"
           "   </rect>\n"
           "  </property>\n"
           "  <property name=\"toolTip\" >\n"
           "   <string>The current time</string>\n"
           "  </property>\n"
           "  <property name=\"whatsThis\" >\n"
           "   <string>The analog clock widget displays the current time.</string>\n"
           "  </property>\n"
           " </widget>\n"
           "</ui>\n";
}

QString widgetPlugins::includeFile() const
{
    return QStringLiteral("mainwindow.h");
}

widgetplugin.h

#ifndef WIDGETPLUGINS_H
#define WIDGETPLUGINS_H
#include<QtUiPlugin/QDesignerCustomWidgetInterface>
#include<QObject>
#include<QString>
#include<QIcon>
#include<QWidget>
#include"mainwindow.h"
class MainWindow;
class widgetPlugins:public QObject,QDesignerCustomWidgetInterface
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QDesignerCustomWidgetInterface")
    Q_INTERFACES(QDesignerCustomWidgetInterface)
public:
    explicit widgetPlugins(QObject *parent = nullptr);
      bool isContainer() const override;
       bool isInitialized() const override;
       QIcon icon() const override;
       QString domXml() const override;
       QString group() const override;
       QString includeFile() const override;
       QString name() const override;
       QString toolTip() const override;
       QString whatsThis() const override;
       QWidget *createWidget(QWidget *parent) override;
       void initialize(QDesignerFormEditorInterface *core) override;

   private:
       bool initialized = false;

};

#endif // WIDGETPLUGINS_H

.pro file

CONFIG      += plugin
TEMPLATE    = lib
QT          += widgets uiplugin
INCLUDEPATH    +="C:\Users\Kits-User1\Documents\QT_projects\custmW\widget"

TARGET = $$qtLibraryTarget($$TARGET)

target.path = $$[QT_INSTALL_PLUGINS]C:\Users\Kits-User1\Documents\QT_projects\custmW\designer
INSTALLS += target



HEADERS += \
    widgetplugins.h

SOURCES += \
    widgetplugins.cpp

DISTFILES += \
    Clock.json

i am getting error of :

: error: undefined reference to `MainWindow::MainWindow(QWidget*)'

in QWidget *widgetPlugins::createWidget(QWidget *parent) function.

J.Hilk

hi @hjohn ,

I would suggest removing
in Qwidget plugin:

#include"mainwindow.h"
class MainWindow;

from your class.
In your class there's no MainWindow object or class pointer created, so its uneeded and apparently the source of your error.

raven-worx

@hjohn said in Qwidget plugin:

: error: undefined reference to `MainWindow::MainWindow(QWidget*)'

means that the linker can't find the implementation of MainWindow.

~~Did you add the cpp file to the project, so it gets compiled along with your plugin?~~
Nevermind, you've posted your pro file. In there the files for your MainWindow class are missing.

hjohn

@J.Hilk i have tried to remove class mainwindw;
but it still give same error

J.Hilk

@hjohn
removing #include"mainwindow.h" is actually more important

hjohn

@J.Hilk then how can i create mainwindow object in that class.I think it will give error of undeclare.

hjohn

@raven-worx I don't think so

jsulm

@hjohn Include #include"mainwindow.h" in your cpp file not header file.

hjohn

@jsulm it makes no difference.

jsulm

@hjohn That's because your pro file is missing mainwindow.*

HEADERS += \
    widgetplugins.h
    ?

SOURCES += \
    widgetplugins.cpp
    ?

But onw question: is this main window part of your plugin or main application?

hjohn

@jsulm it is partof main application.I want to use it in plugin.

jsulm

@hjohn Why do you want to access the main window directly from the plug-in? It would be better to communicate via signals/slots.

raven-worx

@hjohn said in Qwidget plugin:

@raven-worx I don't think so

you don't think what?!
If you want to use it you have to tell the compiler/linker tell where to find it...

hjohn

@jsulm I am implementing qwidgetplugin with reference of http://doc.qt.io/qt-5/qtdesigner-customwidgetplugin-example.html

jsulm

@hjohn You are aware that this link describes how to implement a plug-in for QtDesigner? Do you want a plug-in for QtDesigner or for your application? And in that example I can't see the plug-in using the main window. So again: why do you want to access main window from your plug-in directly?

hjohn

@jsulm yeah i want plug-in for Qt designer.i have implemented same way as mentioned. Here is aq misunderstanding of "mainwindow" name. I have just give different name to the class.the definition and characteristics are same.

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include<QWidget>
#include<QObject>
#include<QtUiPlugin/qdesignerexportwidget>
class MainWindow : public QWidget
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
protected:
    void paintEvent(QPaintEvent *event) override;

};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include <QMouseEvent>
#include <QPainter>
#include <QTime>
#include <QTimer>

MainWindow::MainWindow(QWidget *parent)
    : QWidget(parent)
{
    QTimer *timer = new QTimer(this);
    connect(timer, &QTimer::timeout, this, QOverload<>::of(&QWidget::update));
    timer->start(1000);

    setWindowTitle(tr("Analog Clock"));
    resize(200, 200);
}




void MainWindow::paintEvent(QPaintEvent *)
{
    static const QPoint hourHand[3] = {
        QPoint(7, 8),
        QPoint(-7, 8),
        QPoint(0, -40)
    };
    static const QPoint minuteHand[3] = {
        QPoint(7, 8),
        QPoint(-7, 8),
        QPoint(0, -70)
    };

    QColor hourColor(127, 0, 127);
    QColor minuteColor(0, 127, 127, 191);

    int side = qMin(width(), height());
    QTime time = QTime::currentTime();

    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);
    painter.translate(width() / 2, height() / 2);
    painter.scale(side / 200.0, side / 200.0);

    painter.setPen(Qt::NoPen);
    painter.setBrush(hourColor);

    painter.save();
    painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
    painter.drawConvexPolygon(hourHand, 3);
    painter.restore();

    painter.setPen(hourColor);

    for (int i = 0; i < 12; ++i) {
        painter.drawLine(88, 0, 96, 0);
        painter.rotate(30.0);
    }

    painter.setPen(Qt::NoPen);
    painter.setBrush(minuteColor);

    painter.save();
    painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
    painter.drawConvexPolygon(minuteHand, 3);
    painter.restore();

    painter.setPen(minuteColor);

    for (int j = 0; j < 60; ++j) {
        if ((j % 5) != 0)
            painter.drawLine(92, 0, 96, 0);
        painter.rotate(6.0);
    }
}

jsulm

@hjohn Then please add your mainwindow.h|cpp to the pro file as @raven-worx already suggested.

hjohn

@jsulm okay thanks.. i will try as u have guided.
one last question how Qdesigner is differ from normal gui application.

jsulm

@hjohn It is simply a Qt application. But it provides a plug-in interface to add functionality to it. I mean functionality specific for QtDesigner.

hjohn

@jsulm Qtdesigner does not contain any .ui file.i mean it is custom implementation .am i right?

In other plugins example the project having subproject.for ex: gui application is the parent project and plugin lib contain in sub-project.Can we use same method in this qtdesigner plugin.