Signals and slots from runtime-loaded UI-files

VVCephei

Good Morning!

I was just playing with loading UI-files at runtime. I have a menubar with some dropdown menus and some clickable entries. When I click on "Settings", a UI-file will be loaded from the applications resource file and shows up with some buttons and edit fields.

My question now is:

How can I implement signals and slots for the elements from the UI-files since I have no *.cpp or *.h files for them?

Thank you,

Ceriana

SGaist

Hi,

You would have to create a widget containing the slots needed and call QMetaObject::connectSlotsByName on that widget.

Have a look at the Calculator Builder example

Hope it helps

unixmania

hi. ui file allow to define connections into itself. e.g a_ui_file.ui:
@
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>Form</class>
<widget class="QWidget" name="Form">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>400</width>
<height>300</height>
</rect>
</property>
<property name="windowTitle">
<string>Form</string>
</property>
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>130</x>
<y>130</y>
<width>125</width>
<height>33</height>
</rect>
</property>
<property name="text">
<string>PushButton</string>
</property>
</widget>
</widget>
<resources/>

<connections>
<connection>
<sender>pushButton</sender>
<signal>clicked()</signal>
<receiver>Form</receiver>
<slot>close()</slot>
<hints>
<hint type="sourcelabel">
<x>192</x>
<y>146</y>
</hint>
<hint type="destinationlabel">
<x>199</x>
<y>149</y>
</hint>
</hints>
</connection>
</connections>
</ui>
@
Also you can look theese.
http://qt-project.org/doc/qt-5.1/qtuitools/quiloader.html
http://qt-project.org/doc/qt-5.1/qtquick/qml-qtquick2-loader.html
http://qt-project.org/doc/qt-5.1/qtdesigner/qformbuilder.html

edit: i wonder too.i try it for see whether works or not.

VVCephei

[quote author="SGaist" date="1377182562"]Hi,

You would have to create a widget containing the slots needed and call QMetaObject::connectSlotsByName on that widget.

Have a look at the Calculator Builder example

Hope it helps[/quote]

I dont really understand how to do this. I created a QWidget in the mainwindow-class, but I dont understand what you mean by "containing the slots" and which object to pass to connectSlotsByName.

The calculator example uses QML, or are there any more calculators I did not see?

[quote author="unixmania" date="1377183604"]hi. ui file allow to define connections into itself. e.g a_ui_file.ui:
@
//
@
[/quote]

Yes, but I want to edit the C++ code for those slots, for example if I do changes on a runtime-loaded QDialog, that I can create a save button in whose slot the data from some QLineEdits gets saved into a configurationfile.

unixmania

it seems that QUiLoader::createWidget() is usable for this job.

VVCephei

Sorry, I have no idead how to use it. I looked up QUiLoader::createWidget() in the Qt Assistant, but when I try to get this list, my program crashes:

@
void MainWindow::openSettings()
{
QUiLoader loader;

QFile file&#40;":/test.ui"&#41;;
file.open(QFile::ReadOnly&#41;;

QWidget *wid = loader.load(&file, this);
*this->widglist = loader.availableWidgets();

wid->show();

}
@

Also, I have no idea what this plugin path means, the form is stored inside the resource file.

unixmania

i done it for you ;) main.cpp:
@
#include "test.h"
int main(int argc,char* argv[]){
QApplication app(argc, argv);
Ui::Form ui;
ui.setupUi();
return app.exec();
}
@
test.h:
@
#ifndef TEST_H
#define TEST_H

#include <QtCore/QVariant>
#include <QtWidgets/QAction>
#include <QtWidgets/QApplication>
#include <QtWidgets/QButtonGroup>
#include <QtWidgets/QHeaderView>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QWidget>
#include <QtCore/QFile>
#include <QtUiTools/QUiLoader>

QT_BEGIN_NAMESPACE

class Ui_Form:public QWidget
{
Q_OBJECT
private:

QUiLoader loader;

signals:

void call_wid(&#41;;

private slots:

void emitter(&#41;{
    emit call_wid(&#41;;
}

void save(&#41;{
    QFile file&#40;"add.ui"&#41;;  // same directory where program in
    QWidget* my=loader.load(&file,this&#41;;
    my->setGeometry(QRect(110,100, 125, 33&#41;&#41;;
    my->show();
}

public:
QPushButton *pushButton;

void setupUi()
{
    this->setObjectName("Form");
    this->resize(400, 300);
    pushButton = new QPushButton(this);
    pushButton->setObjectName("pushButton");
    pushButton->setGeometry(QRect(110, 20, 125, 33));
    //QWidget *wid = loader.load(&file,Form);
    connect(this, SIGNAL(call_wid()),this,SLOT(save()));
    connect(pushButton, SIGNAL(clicked()),this,SLOT(emitter()));
    this->setWindowTitle("Form");
    pushButton->setText("CALL");
    this->show();
} // setupUi

};
namespace Ui {
class Form: public Ui_Form {};
} // namespace Ui
QT_END_NAMESPACE
#endif // TEST_H
@
and test.pro
@
TEMPLATE = app
TARGET = test
INCLUDEPATH += .
QT += widgets uitools
HEADERS += test.h
SOURCES += main.cpp
@
NOTICE: i am on 64bit archlinux desktop with qt 5.1.0
EDIT: Ahh sorry and add.ui:
@
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>200</x>
<y>250</y>
<width>80</width>
<height>33</height>
</rect>
</property>
<property name="text">
<string>Save</string>
</property>
</widget>
</ui>
@