QT QMediaPlayer窗口小部件导致白色小窗口

Question

I want to add a videoplayer inside of a qtabwidget in my .ui form file. When the program is ran (Windows 8) the program window is a small white box (not what my .ui form is) and the video plays (you can hear it). Also, if I comment out everything after “ui->Information->addTab(videoWidget, “video”);” the program's UI loads like normal and the new tab is created “video”, however nothing works cause the mediaPlayer code is commented out. This is the code for the media widget:

mainwin.h

private:
    QMediaPlayer * mediaPlayer;

mainwin.cpp

ui->setupUi(this);
mediaPlayer = new QMediaPlayer();
QVideoWidget *videoWidget = new QVideoWidget();
ui->Information->addTab(videoWidget, "video");
mediaPlayer->setVideoOutput(videoWidget);
mediaPlayer->setMedia(QUrl("link"));
mediaPlayer->play();

Can someone help? Thanks!

EDIT: Looking over examples from qt I noticed "mediaPlayer(0, QMediaPlayer::VideoSurface)" when the window is being created if I were to do this I would get:

Project::Project(QWidget *parent) :
QMainWindow(parent),
mediaPlayer(0, QMediaPlayer::VideoSurface),
ui(new Ui::Project)
{
ui->setupUi(this);

This results in a few errors, "error: expression list treated as compound expression in mem-initializer [-fpermissive] mediaPlayer(0, QMediaPlayer::VideoSurface)", "warning: left operand of comma operator has no effect [-Wunused-value]", and "error: cannot convert 'QMediaPlayer::Flag' to 'QMediaPlayer*' in initialization".

Answer 1

I had the same problem after embedding the complete QT media player example in my QT 5.5.0 project. After starting playing the video, a white box would show up in left-top corner.

I noticed that the player would actually make my application toolbar (partially) white, but if the toolbar was hidden, it would add the white box.

Since I did not need the toolbar, I fixed this by removing the toolbar instead of hiding it. In QT designer, right-click in the toolbar, then "Remove Toolbar ".