Support_QT_Homework_PictureViewer

[cprogcoder]

Hello,
I need support regarding the following code. There are some problems which do not work properly.

Thank you in advance,

The Task is :
Please prepare a program which shows for a picture presentation. It should be loaded two different pictures, which
should be shown each for five seconds (like a flip-flop).
After start the program this should be work automatically. The pictures could be directly given which your own path.
Additionally the program should be able with a "end" button.

What doenst work properly :
I had tried to to load the two pictures and and let them show for each of 5 sec. with a Timer.
This doesnt work directly as it should be and I have to use the QMessageBox Button each time and push it.
I think there is a logical failure or failures in it.

The "bildbetrachter.cpp" file :

//die Header-Dateien einbinden
#include "bildbetrachter.h"
#include <QPixmap>
#include <QMessageBox>
#include <QFileDialog>
#include <QDateTime>
#include <QMouseEvent>
#include <QLCDNumber>

//der Konstruktor
Bildbetrachter::Bildbetrachter()
{
//die Größe und den Titel setzen
resize(380,400);
setWindowTitle("Bildbetrachter");

//den Timer für Bild1 erzeugen
timerZeit = new QTimer(); //Bild1
//das Signal timeout des Timers mit dem Slot verbinden
QObject::connect(timerZeit, SIGNAL(timeout()), this, SLOT(timerZeitSlot())); //Bild1

//den Timer für Bild2 erzeugen
timerDatum = new QTimer(); //Bild2
QObject::connect(timerDatum, SIGNAL(timeout()), this, SLOT(timerDatumSlot()));//Bild2

bildLabel1 = new QLabel(this);
bildLabel1->setGeometry(10, 10, 10, 10);

bildLabel2 = new QLabel(this);
bildLabel2->setGeometry(10, 10, 10, 10);

//der Programmstart-Button um die Bilder jeweils für 5 Sek.anzuzeigen
startButton = new QPushButton(this);
startButton->setGeometry(250, 10, 100, 30);
startButton->setText("Programmstart");
QObject::connect(startButton, SIGNAL(clicked()), this, SLOT(timerZeitSlot()));

//der Beenden-Button
beendenButton = new QPushButton(this);
beendenButton->setGeometry(250, 45, 100, 30);
beendenButton->setText("Beenden");
QObject::connect(beendenButton, SIGNAL(clicked()), this, SLOT(close()));

}

//die Methode für die Anzeige - Bild1
void Bildbetrachter::timerZeitSlot() //Bild1
{
timerZeit->start(5000);
//das Bild1 anzeigen
zeigeBild1();

}

//die Methode für den Timer des Datums
void Bildbetrachter::timerDatumSlot()
{
//die Methode stopDatum() aufrufen
stopDatum();

}

void Bildbetrachter::zeigeBild1()
{
QPixmap bild1;

if (timerZeit->isActive()==false)
    return;
else
{
bild1.load("C:/Qt/Bilder/1.jpg");
//die Größe wird dabei an die Breite 200 angepasst
bild1 = bild1.scaledToWidth(200);
//im Label anzeigen
bildLabel1->setPixmap(bild1);
//die Größe des Labels an die Größe des Bildes anpassen
bildLabel1->resize(bild1.size());
QMessageBox::information(this,"1","1");

stopUhrzeit();
}

}

//die Methode zeigeDatum()
void Bildbetrachter::zeigeBild2() //Bild2
{
QPixmap bild2;

if (timerDatum->isActive()==false)
{stopDatum();
    return;
}
else
{
if (timerDatum->isActive()==true)
    {
bild2.load("C:/Qt/Bilder/2.jpg");
//die Größe wird dabei an die Breite 200 angepasst
bild2 = bild2.scaledToWidth(200);
//im Label anzeigen
bildLabel2->setPixmap(bild2);
//die Größe des Labels an die Größe des Bildes anpassen
bildLabel2->resize(bild2.size());
QMessageBox::information(this,"2","Bild2");


   }
}

}

//die Methode stopUhrzeit()- Bild1 stoppen
void Bildbetrachter::stopUhrzeit() //Bild1
{
//den Timer für Bild-1 anhalten
timerZeit->stop(); //Bild1
bildLabel1->clear();
//den Timer für Bild-2 starten
timerDatum->start(5000); //Bild2
//Bild-2 Anzeige;
zeigeBild2(); //Bild2 anzeigen
}

//die Methode stopDatum()
void Bildbetrachter::stopDatum() //Bild2
{
//QMessageBox::information(this,"2","Bild2");

//den Timer für Bild-2 anhalten
timerDatum->stop(); //Bild2
bildLabel2->clear();
//den Timer für Bild-2 starten
timerZeit->start(5000); //Bild1
//Bild-1 Anzeige;
zeigeBild1(); //Bild1 anzeigen

}

---

The Header File "bildbetrachter.h"

#ifndef BILDBETRACHTER_H
#define BILDBETRACHTER_H

//die Header-Dateien einbinden
#include <QWidget>
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QLCDNumber>
#include <QTimer>
#include <QMouseEvent>
#include <QDateTime>

//oder auch
//#include <QtWidgets>

//unsere eigene Klasse erbt von QWidget
class Bildbetrachter : public QWidget
{
//das Makro Q_OBJECT
Q_OBJECT
public:
//der Konstruktor
Bildbetrachter();

//die Methoden und Attribute
private:
    void zeigeUhrzeit(); //Bild1
    void zeigeDatum();   //Bild2

    void stopUhrzeit();  //Bild1
    void stopDatum();    //Bild2


    bool doppelpunkt;
    //der erste Timer
    QTimer* timerZeit;   //Bild1
    //der zweite Timer
    QTimer* timerDatum;  //Bild2


//die Slots
public slots:
    //void oeffneBilddatei();
    //void waehleDateiAus();
      void zeigeBild1();
      void zeigeBild2();

private slots:
//die Methode für den ersten Timer
      void timerZeitSlot();
//die Methode für den zweiten Timer
      void timerDatumSlot();


private:
    //die Attribute für die Widgets
    QLCDNumber *lcdnumber;
    QLabel* einLabel, *bildLabel1,*bildLabel2;
    QLineEdit* eingabeZeile;
    QPushButton* oeffnenButton, *beendenButton, *startButton,*auswaehlenButton;

};
#endif

The main.cpp file

#include <QApplication>
#include "bildbetrachter.h"

int main(int argc, char argv[])
{
QApplication app(argc, argv);
//das Haupt-Widget erzeugen und anzeigen
Bildbetrachter betrachter = new Bildbetrachter();
betrachter->show();

return app.exec();

}

[A Former User]

Hi! Your solution looks pretty complicated. Here's some inspiration for a simpler one:

#include <QApplication>
#include <QWidget>
#include <QVBoxLayout>
#include <QLabel>
#include <QPushButton>
#include <QVector>
#include <QPixmap>
#include <QTimer>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QWidget mainWidget;
    auto layout = new QVBoxLayout(&mainWidget);
    auto label = new QLabel(&mainWidget);
    auto button = new QPushButton("End", &mainWidget);
    label->setScaledContents(true);
    label->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    layout->addWidget(label);
    layout->addWidget(button);
    mainWidget.setLayout(layout);

    auto const pixmaps = QVector<QPixmap>()
        << QPixmap("/home/user/pic1.jpg")
        << QPixmap("/home/user/pic2.jpg");
    int current = 0;
    label->setPixmap(pixmaps.at(current));

    QTimer timer;
    timer.start(5000);

    QObject::connect(button, &QPushButton::clicked, &mainWidget, &QWidget::close);
    QObject::connect(&timer, &QTimer::timeout, [&](){current = (current + 1) % pixmaps.size(); label->setPixmap(pixmaps.at(current));});

    mainWidget.showFullScreen();

    return a.exec();
}

[cprogcoder]

Thank you very much for your support.
I have tried to entry your code but it gives still some failure.
The code is actually ; but it gives the failure in project environment that "pixmap is not defined in this scope" and pixmap
does not name a type. Could you support to clarify this also ?

Thank you in advance,

#include "mainwindow.h"
#include <QApplication>
#include <QWidget>
#include <QVBoxLayout>
#include <QLabel>
#include <QPushButton>
#include <QVector>
#include <QPixmap>
#include <QTimer>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QPushButton *button;
QLabel *label;
QVBoxLayout *layout;
//QPixmap *pixmaps;

QWidget mainWidget;
layout = new QVBoxLayout(&mainWidget);
label = new QLabel(&mainWidget);
button = new QPushButton("End", &mainWidget);
label->setAlignment(Qt::AlignCenter);
label->setScaledContents(true);
label->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
layout->addWidget(label);
layout->addWidget(button);
mainWidget.setLayout(layout);

auto const pixmaps = QVector<QPixmap>()
        << QPixmap("/home/user/pic1.jpg")
        << QPixmap("/home/user/pic2.jpg");
    int current = 0;
    label->setPixmap(pixmaps.at(current));

    QTimer timer;
    timer.start(5000);

    QObject::connect(button, &QPushButton::clicked, &mainWidget, &QWidget::close);
    QObject::connect(&timer, &QTimer::timeout, [&](){current = (current + 1) % pixmaps.size(); label->setPixmap(pixmaps.at(current));});

    mainWidget.showFullScreen();

    return a.exec();

}

[mrjj]

Hi
What Qt version + compiler are you using ?
I tried the code from @Wieland and got no errors so what line
exactly says "pixmap is not defined in this scope" ?

The use of lambdas

( the  [&](){} syntax) 

requires a c++2011 enabled compiler and if you are using say
Qt 5.5, you might need
CONFIG += c++11
in the .pro file ( the project file)
Run qmake from menu after inserting.

[cprogcoder]

Hello,

my version was Qt 5.0.2 (32 bit) and I added the CONFIG +=c++11 in the project file,
Thank you very much it worked properly.

Best Regards,