I am using Qt Version 5.14.1.
When I was trying to play a video(.mp3), the program stopped working
And given error is DirectShowPlayerService::doSetUrlSource: Unresolved error code 0x8007007b ()
AudioPlayer::AudioPlayer(QObject *parent)
: QObject(parent)
, m_backgroundMusic(NULL) //QMediaPlayer * m_backgroundMusic
{
QUrl backgroundMusicUrl = QUrl::fromLocalFile(":/music/8bitDungeonLevel.mp3");
if (QFile::exists(backgroundMusicUrl.toLocalFile()))
{
m_backgroundMusic = new QMediaPlayer(this);
QMediaPlaylist * backgroundMusicList = new QMediaPlaylist();
QMediaContent media(backgroundMusicUrl);
backgroundMusicList->addMedia(media);
backgroundMusicList->setCurrentIndex(0);
backgroundMusicList->setPlaybackMode(QMediaPlaylist::CurrentItemInLoop);
m_backgroundMusic->setPlaylist(backgroundMusicList);
}
}
void AudioPlayer::startBGM()
{
if (m_backgroundMusic)
{
qDebug() << m_backgroundMusic;
m_backgroundMusic->play();
}
}
the output as below
QMediaPlayer(0x3987eb0)
DirectShowPlayerService::doSetUrlSource: Unresolved error code 0x8007007b ()
I search the Internet and add LAV Filters to QT installation directory
, I also restart the computer but nothing changes.So how to fix it?
Your path in QUrl::fromLocalFile(":/music/8bitDungeonLevel.mp3") appears to be off, AFIK there is no (at least not common) path naming scheme that uses : to begin paths.
UPDATE:
I was told that :/ refers to resources that have been compiled into a Qt application, I think using the Qt Resource Compiler (rcc)
Use this code to load mp3 from resources:
m_mediaPlayer.setMedia(QUrl("qrc:/Audio/MouseOver.mp3"));
(do no forget do delete fromLocalFile)
Related
So I'm trying to have my "button" directly execute a Batch file, important here is that I don't want it to show me a dialogue and make me chose the path, which is the problem I'm having right now with the following code
void MainWindow::on_pushButton_clicked()
{
QString filename=QFileDialog::getOpenFileName(
this,
tr("Open File"),
"C://",
"All files (*.*);;Text File (*.txt);;Music file (*.mp3)");
}
I think this is probably really simple, but i can't get it, I'm not even learning c++ at the moment but my boss asked me to create something out of my scope (wants me to create a GUI for a batch file and have them interact) and I thought of this approach, which is just creating a GUI that executes it.
I've looked at this question: asked to execute an external program with Qt
but they don't talk about how the file path can directly be added into the code, or if I should even be using Qprocess and how, and if I can pass it through "clicked" function.
I'm really inexperienced, all of the code above I got with the help of the internet, but I really don't know how to program using c++
so could someone please be kind enough to show me how a file path can be added to the code, assuming it's in C:\Users\name_goes_here\Downloads
I'd really appreciate it :D
I'd recommend using QProcess for anything "execute external program" with Qt.
You could do it like this:
void MainWindow::on_pushButton_clicked()
{
QProcess process;
process.start("C:/Users/name_goes_here/Downloads/yourfile.bat");
process.waitForFinished(); // Assuming that you do want to wait for it to finish before the code execution resumes
}
Note the "/" in the path. Only Windows uses the messed up "\" for path separation, which would require you to write "C:\\Users\\.." in any string in C++ as "\" needs to be escaped.
Luckily, Qt uses "/" as the universal separator and translates it to whatever the OS needs as required. So you should just use "/" whenever working with Qt.
This is from the Qt documentation:
Qt uses "/" as a universal directory separator in the same way that "/" is used as a path separator in URLs. If you always use "/" as a directory separator, Qt will translate your paths to conform to the underlying operating system.
And finally, if you don't know how to code in C++, shouldn't you be learning that first instead of trying to execute batch files from within a library as complex as Qt? Sounds like you're trying to do too many new things at once.
This is fairly simple merging your source and the one you linked:
void MainWindow::on_pushButton_clicked()
{
QProcess::execute(
QString::fromLatin1(
"cmd.exe /c C:\\Users\\name_goes_here\\Downloads\\file.bat"));
}
Notes:
I used QProcess::execute() instead of QProcess::start() to make things even simpler.
To achieve execution of the batch file, I pass it to cmd32.exe as this is the interpreter which is responsible.
As MCVE testQProcessBatch.cc:
// Qt header:
#include <QtWidgets>
void on_pushButton_clicked()
{
#if 0 // WORKS:
QProcess::execute(
QString::fromUtf8("cmd.exe /c C:\\Users\\Scheff\\Downloads\\testBatch.bat"));
#else // WORKS AS WELL:
QProcess::execute(
QString::fromUtf8("C:\\Users\\Scheff\\Downloads\\testBatch.bat"));
#endif // 0
}
int main(int argc, char **argv)
{
qDebug() << "Version:" << QT_VERSION_STR;
// main application
QApplication app(argc, argv);
QMainWindow qWin;
QPushButton qBtn(QString::fromLatin1("Start cmd"));
qWin.setCentralWidget(&qBtn);
qWin.show();
QObject::connect(&qBtn, &QPushButton::clicked,
&on_pushButton_clicked);
// run application
return app.exec();
}
and the test batch file testBatch.bat:
echo "This is testBatch.bat"
pause
Tested with VS2013 on Windows 10:
Thanks for contributing guys!
I tried using the QProcess method but I think I'm too inexperienced when it comes to figuring out problems associated with it (which I did face when using this method). the CMD route is probably good but I also thought it was too difficult and both of these methods didn't work for me.
Here's what I have now (thanks to Detonar and ymoreau) and and it seems to be doing the job, this might not be the most optimal approach, but it worked for me!
I included QDesktopServices and QUrl
void MainWindow::on_pushButton_clicked()
{
QString filename="C:\\Users\\Name_goes_here\\Downloads\\test.bat";(
this);
hide(); //optional
QDesktopServices::openUrl(QUrl("file:///"+filename,QUrl::TolerantMode));
}
I would appreciate if anybody can help me with this (did not find anything relevant with Google).
I am trying to get positioning info in iOS using Qt. Have tried the simulator as well as a real iPhone. I get at source from QGeoPositionInfoSource that says "corelocation", but source does not seem to emit a signal since positionUpdated never gets called. Any ideas?
Here is my code:
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QGeoPositionInfoSource *source = QGeoPositionInfoSource::createDefaultSource(this);
if (source){
connect(source, SIGNAL(positionUpdated(QGeoPositionInfo)),this, SLOT(positionUpdated(QGeoPositionInfo)));
source->setUpdateInterval(100);
source->startUpdates();
qDebug()<<"Source found";
qDebug()<<source->availableSources();
}else{
qDebug()<<"Failed source";
}
}
void MainWindow::positionUpdated(const QGeoPositionInfo &info)
{
qDebug() << "Position updated:" << info;
}
UPDATE-----------------------------
Getting the error from source says "An unidentified error occurred.". Not very helpful but at least its not an issue related to lacking privileges (error 0).
This post solved my problem. You have to edit the info.plist file (from xcode or with a text editor).
Location Services not working in iOS 8
I've got this C++ code:
bool load ()
{
const QString * filename = openFileDialog(QFileDialog::AcceptOpen, QFileDialog::ExistingFile);
if (filename != 0)
return load(*filename);
else return false;
}
const QString * openFileDialog (QFileDialog::AcceptMode acceptMode, QFileDialog::FileMode mode)
{
QFileDialog dialog;
dialog.setAcceptMode(acceptMode);
dialog.setFileMode(mode);
dialog.show();
QStringList files = dialog.selectedFiles();
if (files.isEmpty()) return 0;
return new QString(files.at(1));
}
Now, I get the following error:
KGlobal::locale::Warning your global KLocale is being recreated with a valid main component instead of a fake component, this usually means you tried to call i18n related functions before your main component was created. You should not do that since it most likely will not work
The file dialog never appears.
I'm using Debian wheezy (german), KDE 4.8.4, Qt 4.8.2 and GCC 4.7.2
I'm late to the party, but this is apparently a very old issue anyway. It was solved 5 years ago, here: http://pyqt.riverbankcomputing.narkive.com/GMKOTskG/a-dire-warning-message#post16
The short answer:
When opening the file dialog, it's using the "system" file dialog. In this case, the system dialog is KDE, and an issue that is blamed on a KDE library produces that warning. Want to avoid the issue? Don't use the "system" file dialog.
In your openFileDialog function, simply add:
dialog.setOption(QFileDialog::DontUseNativeDialog)
This solution worked for me. (I'm using PyQt4, but was having the same symptoms.)
I am new to qt. I want to make a simple project that will print text from the printer.
whenever I am using
QPrinter printer;
QPrintDialog *dialog = new QPrintDialog(&printer, this);
dialog->setWindowTitle(tr("Print Document"));
if (editor->textCursor().hasSelection())
dialog->addEnabledOption(QAbstractPrintDialog::PrintSelection);
if (dialog->exec() != QDialog::Accepted)
return;
or this
QPrinter printer(QPrinter::HighResolution);
printer.setOutputFileName("print.ps");
QPainter painter;
painter.begin(&printer);
for (int page = 0; page < numberOfPages; ++page) {
// Use the painter to draw on the page.
if (page != lastPage)
printer.newPage();
}
painter.end();
I just copy pasted this to my mainwindow.cpp(and tried pasting it to main.cpp too),to check if it works. It does not.
I am getting several errors like these
mainwindow.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual _thiscall QPrinter::~QPrinter(void)" (_imp_??1QPrinter##UAE#XZ) referenced in function "private: void __thiscall MainWindow::on_pushButton_clicked(void)" (?on_pushButton_clicked#MainWindow##AAEXXZ).
could someone tell me step by step, how to print to a printer?
I also checked a lot online, but did not get any relevant tutorial , or even an example.
so, PLEASE write it here instead of linking me to another page.
I did some quick research being kind of surprised by your comments. The QtPrintSupport did change, so use for Qt5 (Detailed Description):
In Pro file:
QT += core gui printsupport
In cpp file:
#include <QtPrintSupport>
For printing from your QTextEdit *editor use:
editor->document()->print(&printer);
I'm writing a GUI application, using Qt, which links to a third-party DLL that sometimes sends error messages to stderr. I'd like these error messages to be displayed in a window within my GUI.
I couldn't find an established way to redirect stderr (as opposed to std::cerr) even after much searching, so I wrote the following class myself:
class StdErrRedirect : public QObject
{
Q_OBJECT
public:
// Constructor
StdErrRedirect(QTextEdit *errorLog,
QObject *parent = NULL);
// Destructor
~StdErrRedirect();
private slots:
void fileChanged(const QString &filename);
private:
QFile tmp;
QFileSystemWatcher watcher;
QString tmpFileNameQtFormat;
QString tmpFileNameNativeFormat;
QTextEdit *m_errorLog;
QString oldContent;
};
StdErrRedirect::StdErrRedirect(QTextEdit *errorLog,
QObject *parent)
: QObject(parent)
{
// Store the pointer to the error log window
m_errorLog = errorLog;
// Create a temporary filename: first find the path:
tmpFileNameQtFormat = QDir::tempPath();
// Make sure the closing slash is present:
if (!tmpFileNameQtFormat.endsWith(QChar('/')))
tmpFileNameQtFormat.append(QChar('/'));
// Add the file name itself:
tmpFileNameQtFormat.append("nb_stderrlog");
// Obtain a version of the filename in the operating system's native format:
tmpFileNameNativeFormat = QDir::toNativeSeparators(tmpFileNameQtFormat);
// Set up redirection to this file:
freopen(tmpFileNameNativeFormat.toAscii().constData(), "a+", stderr);
// Initialise the QFileSystemWatcher:
connect(&watcher, SIGNAL(fileChanged(const QString &)),
this, SLOT(fileChanged(const QString &)));
watcher.addPath(tmpFileNameQtFormat);
tmp.setFileName(tmpFileNameQtFormat);
}
StdErrRedirect::~StdErrRedirect()
{
// Ensure the temporary file is properly deleted:
fclose(stderr);
tmp.close();
tmp.open(QIODevice::ReadWrite);
tmp.remove();
}
void StdErrRedirect::fileChanged(const QString &filename)
{
tmp.open(QIODevice::ReadOnly);
QTextStream stream(&tmp);
QString content = stream.readAll();
tmp.close();
// Identify what's new, and just send this to the window:
int newchars = content.size() - oldContent.size();
if (newchars)
{
m_errorLog -> append(content.right(newchars));
oldContent = content;
}
}
If I instantiate this from my main window using:
errorLog = new QTextEdit;
redirector = new StdErrRedirect(errorLog);
... then everything I write to stderr appears in the window.
So far, so good. The problem is that the DLL's output still does not. In a call to a DLL function which emits an error, if I put the code:
if (error != _OK)
{
error.PrintErrorTrace();
fprintf(stderr, "Should have printed an error \r\n");
fflush(stderr);
//fsync(_fileno(stderr)); Linux version
_commit(_fileno(stderr));
return;
}
...then the text "Should have printed an error" appears but the error message itself does not.
Now, I've read somewhere that this is probably because the redirection is being set up after the DLL was loaded at the beginning of the application, and so it's own stderr channel is unaffected. Therefore, I should be able to fix this by loading the DLL dynamically, after setting up the redirection, instead.
Here is my question, then: how do I do this? I can try putting the following code at the beginning of my application:
QLibrary extlib;
extlib.setFileName("libname");
extlib.setLoadHints(QLibrary::ResolveAllSymbolsHint);
extlib.load();
...but on its own it has no effect. I think this is because the linker is still setting the library up to be opened automatically. However, if I remove the DLL from the linker (I'm using VS2008, so I remove extlib.lib from the dependency list) then the application won't compile because the compiler can't find the symbols from the DLL.
So there's obviously something deeply wrong with what I'm trying to do here. Can anybody help?
Thanks,
Stephen.
Does the DLL really write to stderr? Or does it write to GetStdHandle(STD_ERROR_HANDLE) ? The first maps to the second, initially. But with freopen() you merely change the mapping. Anything written to STD_ERROR_HANDLE will still go there.
To redirect everyones error output, you would need SetStdHandle.
There is only one stderr, so my guess is that the problem is not that you need to load the dll dynamically, but somewhere in your redirection code. Your redirection code is written Linux style, where in windows things work differently.
if you could test your application on Linux, It would help to pin point the problem. If it works on Linux, that it is surly the redirection code.
Anyway, you should read some more about redirection and windows, as I don't think that what you are trying to do now will help you.