QMediaPlayer and QMediaPlaylist - problem with next

maniek1310

Hi, I have a problem with the function next (). When you click on the "Next" button, the program automatically closes. Maybe you have any ideas how to fix it?

mainwindow.cpp
@#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtMultimedia/QMediaPlayer>
#include <QTime>
#include <QFileDialog>
#include <QFile>
#include <QFileInfo>
#include <QMediaPlaylist>

using namespace std;

QMediaPlayer *player = new QMediaPlayer();
QMediaPlaylist *playlist = new QMediaPlaylist;

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

QObject::connect(player, SIGNAL(positionChanged(qint64)), this, SLOT(aktualna_pozycja(qint64)));

}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::run_file(QString file)
{
QFile file_1(file);

QFileInfo fileInfo(file_1.fileName());
QString name(fileInfo.fileName());

ui->name_music->setText(name);

playlist->addMedia(QUrl::fromLocalFile&#40;file&#41;);
playlist->addMedia(QUrl::fromLocalFile&#40;"K:/Anakonda.mp3"&#41;);
playlist->setCurrentIndex(0);

player->setPlaylist(playlist);

player->setVolume(80);
//player->setMedia(QUrl::fromLocalFile&#40;file&#41;);
player->play();

//ui->label_2->setText(file);

}

void MainWindow::on_pushButton_clicked()
{
player->play();
}

void MainWindow::on_pushButton_2_clicked()
{
player->stop();
}
void MainWindow::on_horizontalSlider_sliderMoved(int position)
{
player->setVolume(position);
ui->glosnosc->setText(QString::number(position) + QString("%"));
}

void MainWindow::aktualna_pozycja(qint64 position)
{
qint64 duration = player->duration();

int ile_procent = 0;
int seconds1 = (position / 1000) % 60;
int minutes1 = (position / 60000) % 60;
int hours1 = (position / 3600000) % 24;
int seconds2 = (duration / 1000) % 60;
int minutes2 = (duration / 60000) % 60;
int hours2 = (duration / 3600000) % 60;

QTime time_akt(hours1, minutes1, seconds1);
QTime time_end(hours2, minutes2, seconds2);

ui->akt_poz->setText(time_akt.toString());
ui->end_poz->setText(time_end.toString());

ile_procent = (position * 100) / duration;

ui->ile_trwa->setValue(ile_procent);

}

void MainWindow::on_pushButton_3_clicked()
{
QString fileName = QFileDialog::getOpenFileName(this, tr("Wybierz piosenkę"), "C:\", tr("Pliki MP3 (*.mp3)"));

if(fileName != "")
    run_file&#40;fileName&#41;;

}

void MainWindow::on_pause_clicked()
{
player->pause();
}

void MainWindow::on_next_file_clicked()
{
playlist->next();
}
@

maniek1310

@refresh

SGaist

Hi,

Please practice some patience. Allow at least 24 hours before bumping your own thread. People on this forum don't necessarily lives in the same time zone as you.

That said, what do you mean by close ? The application just stops ? Crashes ?

maniek1310

Crashes, I just click on the "Next"

SGaist

What does a run with the debugger tell you ?

maniek1310

http://imageshack.com/a/img199/3483/1ljx.png

Console : Rozpoczęto debugowanie
QEventLoop: Cannot be used without QApplication
QObject::connect: Cannot connect (null)::aboutToQuit() to QNativeWifiEngine::closeHandle()

SGaist

How does your main.cpp look like ?

Also, why make player and playlist static ?

maniek1310

main.cpp
@#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec&#40;&#41;;

}
@

mainwindow.h
@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private slots:
void on_pushButton_clicked();

void on_pushButton_2_clicked();

void on_horizontalSlider_sliderMoved(int position);

void aktualna_pozycja(qint64 position);

void on_pushButton_3_clicked();

void run_file&#40;QString file&#41;;

void on_pause_clicked();

void on_next_file_clicked();

void on_pushButton_4_clicked();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H
@

test_sound.pro
@#-------------------------------------------------

Project created by QtCreator 2014-02-04T19:08:13

#-------------------------------------------------

QT += core gui
QT += widgets multimedia
QT += multimedia
QT += core gui multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = test_sound
TEMPLATE = app

SOURCES += main.cpp
mainwindow.cpp

HEADERS += mainwindow.h

FORMS += mainwindow.ui
@

SGaist

Looks right.

Please move both player and playlist has non static member variable of MainWindow and try again

maniek1310

I do not understand. I could explain it somehow differently?

SGaist

@QMediaPlayer *player = new QMediaPlayer();
QMediaPlaylist *playlist = new QMediaPlaylist;@

These are static, remove them. And add two member variable in MainWindow to replace them.

@mainwindow.h
class MainWindow : public QMainWindow {
…

private:
QMediaPlayer *_player;
QMediaPlaylist *_playlist;

}

mainwindow.cpp

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow),
_player(new QMediaPlayer),
_playlist(new QMediaPlayList)
{
ui->setupUi(this);

QObject::connect(_player, SIGNAL(positionChanged(qint64)), this, SLOT(aktualna_pozycja(qint64)));

}
@

Something like that

maniek1310

@mainwindow.h
...
private:
Ui::MainWindow *ui;
QMediaPlayer *player;
QMediaPlayer *playlist;
};@

@mainwindow.cpp
...
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow),
player(new QMediaPlayer),
playlist(new QMediaPlaylist)
{
ui->setupUi(this);

QObject::connect(player, SIGNAL(positionChanged(qint64)), this, SLOT(aktualna_pozycja(qint64)));

}
...
@

błąd: cannot convert 'QMediaPlaylist*' to 'QMediaPlayer*' in initialization
playlist(new QMediaPlaylist)

błąd: 'class QMediaPlayer' has no member named 'addMedia' playlist->addMedia(QUrl::fromLocalFile(file));

SGaist

The error is pretty clear, you declared playlist list as a QMediaPlayer and not QMediaPlayList.

maniek1310

Okay, thank you. Now the program compiles correctly, but it is still the same problem.

After pressing the "Next" button shows up is:

http://imageshack.com/a/img577/9630/0p87.png

SGaist

Run your program using the debugger, that should catch the problem

maniek1310

http://imageshack.com/a/img199/3483/1ljx.png