This is how i am currently choosing the font in my application.
void FontChange()
{
QString filePath = QFileDialog::getOpenFileName(NULL, tr("Open File"),
QStandardPaths::standardLocations(QStandardPaths::FontsLocation)[0],
tr("Fonts (*.ttf);;Everything (*.*)"), nullptr,
QFileDialog::DontUseNativeDialog);
if (filePath.isEmpty())
return;
QlineEditSetFont->setText(filePath);
stdstrLocation = filePath.toStdString();
this->isChanged = true; // this executes the function
}
I want to execute a function whenever i change my selection in the Dialog , currently i have to choose a font and than click on open to execute the function
////////////////////////////////////////////////////////////////////////////
Now i am using a non modal way but how can i determine if cancel has been pressed.
Further Edit
QFileDialog* dialog = new QFileDialog();
dialog->setAttribute(Qt::WA_DeleteOnClose);
dialog->setNameFilter("TTF (*.ttf)");
dialog->setOption(QFileDialog::DontUseNativeDialog);
dialog->setDirectory("C:\\Windows\\Fonts");
QObject::connect(dialog, &QFileDialog::currentChanged, [=](const QString &path) {
qDebug() << path; stdstrLocation = path.toStdString(); this->isChanged = true;
QStringList fileNames = dialog->selectedFiles();
qDebug() << "Selected FIles" << fileNames.size();
});
dialog->show();
You can't use the static convenience method but need to create the QFileDialog instance manually:
auto dialog = new QFileDialog(someParent);
dialog->setWindowTitle(tr("Open File"));
dialog->setDirectory(QStandardPaths::standardLocations(QStandardPaths::FontsLocation)[0]);
dialog->setNameFilter(tr("Fonts (*.ttf);;Everything (*.*)"));
// more setup...
connect(dialog, &QFileDialog::filesSelected, this, [this](const QStringList &selected) {
// handle selection change here
});
if (dialog->exec() == QDialog::Accepted) { // alternatively use open() to avoid blocking exec()
// do something with dialog->selectedFiles()...
}
delete dialog;
Actually, those are two different questions. The one from the title has been already answered. The answer to the second one, namely How can i determine if cancel has been pressed, lies in the documentation of QFileDialog::getOpenFileName itself:
If the user presses Cancel, it returns a null string.
With this in mind, you can do something like:
void FontChange()
{
QString filePath = QFileDialog::getOpenFileName(NULL, tr("Open File"),
QStandardPaths::standardLocations(QStandardPaths::FontsLocation)[0],
tr("Fonts (*.ttf);;Everything (*.*)"), nullptr,
QFileDialog::DontUseNativeDialog);
if (filePath.isNull()) {
// user pressed Cancel
} else if (filePath.isEmpty()) {
return;
} else {
QlineEditSetFont->setText(filePath);
stdstrLocation = filePath.toStdString();
this->isChanged = true; // this executes the function
}
}
You can of course rewrite the if part to be more suitable to your app's logic.
As a side note, QString::isEmpty also implies that it is NULL.
I am trying to implement copy/cut/paste in a complex application.
I have a QGraphicsScene that can contain QGraphicsItem subtypes of varied subtypes, fairly complex (with Item as a second parent storing custom properties).
I would copy/cut selected items, and paste them back in place.
I already have implemented it using a local version: a list of items.
void copyItemsActionOld()
{
foreach(QGraphicsItem* qItem, selectedItems())
{
Item* newItem = (dynamic_cast<Item*>(qItem))->createItemCopy();
m_itemClipboard.append(newItem);
}
}
On paste, I make a copy of all items in clipboard and add them to the scene. So simple.....
BUT
I need to implement it using the global system clipboard.
I saw that creating a custom mime type is as simple as calling setData on a QMimeData object, after I make up a format name... (I hope that is true)
static const QString _mimeType("application/myItem");
void copyItemsAction()
{
QMimeData* _mimeData = new QMimeData;
2 QByteArray _itemData = ?????;
_mimeData->setData(_mimeType, _itemData);
QClipboard* _clipboard = QApplication::clipboard();
_clipboard->clear();
_clipboard->setMimeData(_mimeData);
}
void pasteItemsAction()
{
QClipboard* _clipboard = QApplication::clipboard();
const QMimeData* _mimeData = _clipboard->mimeData();
QStringList _formats = _mimeData->formats();
foreach (QString _format, _formats)
{
if (_format == _mimeType)
{
QByteArray _itemData = _mimeData->data(_mimeType);
3 // then do what ? How do I parse it ?
}
}
}
My questions
1) Are the above fragments for copyItemsAction and pasteItemsAction anywhere close to how clipboard actions should work ?
2) How can I put item data in the QByteArray ?
3) How do I parse the data in QByteArray ?
4) Do I need to register the custom mime-type anywhere else ? (other than what I just did in my two functions); and will it be multi-platform ?
I have already implemented save and load functionality for all items. Something like...
void Item::saveItem(QDataStream &outFile)
{
outFile << type;
outFile << width;
outFile << color.name();
}
Can I use this to place the items data in the QByteArray ? (How ?)
I was on the right track, and I kept adding code to my question until I found how to make it work:
static const QString _mimeType("application/myItem");
void copyItemsAction()
{
QByteArray _itemData;
QDataStream outData(&_itemData, QIODevice::WriteOnly);
outData << selectedItems().size();
foreach(QGraphicsItem* qItem, selectedItems())
{
Item* item = dynamic_cast<Item*>(qItem);
item->saveItem(outData);
}
QMimeData* _mimeData = new QMimeData;
_mimeData->setData(_mimeType, _itemData);
_mimeData->setText("My Items");
QClipboard* _clipboard = QApplication::clipboard();
_clipboard->clear();
_clipboard->setMimeData(_mimeData);
}
void pasteItemsAction()
{
QClipboard* _clipboard = QApplication::clipboard();
const QMimeData* _mimeData = _clipboard->mimeData();
QStringList _formats = _mimeData->formats();
foreach (QString _format, _formats)
{
if (_format == _mimeType)
{
QByteArray _itemData = _mimeData->data(_mimeType);
QDataStream inData(&_itemData, QIODevice::ReadOnly);
int itemsSize;
inData >> itemsSize;
for (int i = 0; i < itemsSize; ++i)
{
Item* item = ...
item->loadItem(inData);
}
}
}
}
So, for question 1, yes I was on the right track;
For questions 2 and 3 - I was able to use a QDataStream to serialize info to/from the QByteArray.
If there is a better / more effective / faster way, I would love to know...
For question 4 - it seems that I can use just about any string, if all I want is to copy/paste within a single instance of my application.
It is also true if I want to use it between multiple applications, multiple instances of my application, or for drag-and-drop - on most platforms. (It does not seem to work between multiple applications/instances in the embedded platform I target.)
Caveat - it fails frequently when another clipboard using application is open, in windows.
What I want:
When I call save(), I would like to use the QFileDialog to get the file, and save ui file with QFormBuilder(because it lets me save ui files recognizable by Qdesigner)
What I have:
I have a method called save()
void MainWindow::save()
{
QString savef = QFileDialog::getSaveFileName(this, tr("Save"), "file", tr("UI files (*.ui)"));
//here down I would like to use the savef to save ui file
QFormbuilder builder;
builder.save(savef, myui);
}
But savef is not QIODevice, and the Qt is complaining about it.
Any idea how I can do it?
Thanks.
You need to create a QFile and pass that to save():
QFile out(savef);
if (!out.open(QIODevice::WriteOnly)) {
const QString error = tr("Could not open %1 for writing: %2").arg(savef, out.errorString());
//report the error in some way...
return;
}
builder.save(&out, myui);
const bool flushed = out.flush();
if (!flushed || out.error() != QFile::NoError) { // QFormBuilder lacks proper error reporting...
const QString error = tr("Could not write form to %1: %2").arg(savef, out.errorString());
//report error
}
When using Qt 5.1 or newer, I'd use QSaveFile instead:
QSaveFile out(savef);
if (!out.open(QIODevice::WriteOnly)) {
const QString error = tr("Could not open %1 for writing: %2").arg(savef, out.errorString());
//report the error in some way...
return;
}
builder.save(&out, myui);
if (!out.commit()) {
//report error
}
i use QNetworkAccessManager post request to a website:
void Spider::getProducts()
{
connect(&manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(getProducts(QNetworkReply*)));
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
request.setUrl(QUrl("http://www.example.com/query"));
for(int i = 0; i < categories.size(); ++i)
{
if(categories[i].isCategory())
{
isSubCategory = false;
emit manager.finished(reply);
}
else
{
for(int page_number = 0; page_number < categories[i].getPageCount(); ++i)
{
isSubCategory = true;
QJsonObject json;
json.insert("NValue", categories[i].getNValue());
json.insert("NodeId", categories[i].getNodeId());
json.insert("StoreId", categories[i].getStoreId());
json.insert("StoreType", categories[i].getStoreType());
json.insert("PageNumber", ++page_number);
json.insert("SubCategoryId", categories[i].getSubCategoryId());
QJsonDocument doc;
doc.setObject(json);
QByteArray request_body = doc.toJson();
manager.post(request, request_body);
}
}
}
}
when i run this program, at beginning, this program run normally, after running for a while, it will stop: neither terminated nor continue to run. i can not figure out why it behavior like this? is there anything that needed to be noticed when use QNetworkAccess? or i am refused by that website? ...
You are using the same QNetworkAccessManager object in a loop multiple times. It is incorrect. For each separate post request you need a separate QNetworkAccessManager object if you want to send requests in parallel. Else if you only want to use a single instance then you need to serialize your post requests by sending next post request when the previous ends in the finished slot.
Updated: Try out this code, it uses single QNetworkAccessManager object, you will need to check for correct place of i++ as per your needs
connect(&manager, SIGNAL(finished(QNetworkReply*)),
this, SLOT(getProducts(QNetworkReply*))); // add this to constructor of your program
void Spider::getProducts()
{
static int i = 0;
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");
request.setUrl(QUrl("http://www.example.com/query"));
while(categories[i].isCategory())
{
isSubCategory = false;
i++;
}
if(i == categories.size())
{
emit allPostRequestsDone();
return;
}
else
{
i++;
if(page_number < categories[i].getPageCount())
{
isSubCategory = true;
QJsonObject json;
json.insert("NValue", categories[i].getNValue());
json.insert("NodeId", categories[i].getNodeId());
json.insert("StoreId", categories[i].getStoreId());
json.insert("StoreType", categories[i].getStoreType());
json.insert("PageNumber", ++page_number);
json.insert("SubCategoryId", categories[i].getSubCategoryId());
QJsonDocument doc;
doc.setObject(json);
QByteArray request_body = doc.toJson();
manager.post(request, request_body);
}
}
}
}
I want to copy a directory from one drive to another drive. My selected directory contains many sub directories and files.
How can I implement the same using Qt?
void copyPath(QString src, QString dst)
{
QDir dir(src);
if (! dir.exists())
return;
foreach (QString d, dir.entryList(QDir::Dirs | QDir::NoDotAndDotDot)) {
QString dst_path = dst + QDir::separator() + d;
dir.mkpath(dst_path);
copyPath(src+ QDir::separator() + d, dst_path);
}
foreach (QString f, dir.entryList(QDir::Files)) {
QFile::copy(src + QDir::separator() + f, dst + QDir::separator() + f);
}
}
Manually, you can do the next things:
1). with func below you generate folders/files list (recursively) - the destination files.
static void recurseAddDir(QDir d, QStringList & list) {
QStringList qsl = d.entryList(QDir::NoDotAndDotDot | QDir::Dirs | QDir::Files);
foreach (QString file, qsl) {
QFileInfo finfo(QString("%1/%2").arg(d.path()).arg(file));
if (finfo.isSymLink())
return;
if (finfo.isDir()) {
QString dirname = finfo.fileName();
QDir sd(finfo.filePath());
recurseAddDir(sd, list);
} else
list << QDir::toNativeSeparators(finfo.filePath());
}
}
2). then you may to start copying files from destination list to the new source directory like that:
for (int i = 0; i < gtdStringList.count(); i++) {
progressDialog.setValue(i);
progressDialog.setLabelText(tr("%1 Coping file number %2 of %3 ")
.arg((conf->isConsole) ? tr("Making copy of the Alta-GTD\n") : "")
.arg(i + 1)
.arg(gtdStringList.count()));
qApp->processEvents(QEventLoop::ExcludeUserInputEvents);
if (progressDialog.wasCanceled()) {
// removing tmp files/folders
rmDirectoryRecursive(tmpFolder);
rmDirectoryRecursive(tmpFolderPlus);
setEnableGUI(true);
return;
}
// coping
if (!QFile::copy(gtdStringList.at(i), tmpStringList.at(i))) {
if (warningFlag) {
QMessageBox box(this);
QString name = tr("Question");
QString file1 = getShortName(gtdStringList.at(i), QString("\\...\\"));
QString file2 = getShortName(tmpStringList.at(i), QString("\\...\\"));
QString text = tr("Cannot copy <b>%1</b> <p>to <b>%2</b>" \
"<p>This file will be ignored, just press <b>Yes</b> button" \
"<p>Press <b>YesToAll</b> button to ignore other warnings automatically..." \
"<p>Or press <b>Abort</b> to cancel operation").arg(file1).arg(file2);
box.setModal(true);
box.setWindowTitle(name);
box.setText(QString::fromLatin1("%1").arg(text));
box.setIcon(QMessageBox::Question);
box.setStandardButtons(QMessageBox::YesToAll | QMessageBox::Yes | QMessageBox::Abort);
switch (box.exec()) {
case (QMessageBox::YesToAll):
warningFlag = false;
break;
case (QMessageBox::Yes):
break;
case (QMessageBox::Abort):
rmDirectoryRecursive(tmpFolder);
rmDirectoryRecursive(tmpFolderPlus);
setEnableGUI(true);
return;
}
}
}
}
And that's all. Good luck!
I wanted something similar, and was googling (in vain), so this is where I've got to:
static bool cpDir(const QString &srcPath, const QString &dstPath)
{
rmDir(dstPath);
QDir parentDstDir(QFileInfo(dstPath).path());
if (!parentDstDir.mkdir(QFileInfo(dstPath).fileName()))
return false;
QDir srcDir(srcPath);
foreach(const QFileInfo &info, srcDir.entryInfoList(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot)) {
QString srcItemPath = srcPath + "/" + info.fileName();
QString dstItemPath = dstPath + "/" + info.fileName();
if (info.isDir()) {
if (!cpDir(srcItemPath, dstItemPath)) {
return false;
}
} else if (info.isFile()) {
if (!QFile::copy(srcItemPath, dstItemPath)) {
return false;
}
} else {
qDebug() << "Unhandled item" << info.filePath() << "in cpDir";
}
}
return true;
}
It uses an rmDir function that looks pretty similar:
static bool rmDir(const QString &dirPath)
{
QDir dir(dirPath);
if (!dir.exists())
return true;
foreach(const QFileInfo &info, dir.entryInfoList(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot)) {
if (info.isDir()) {
if (!rmDir(info.filePath()))
return false;
} else {
if (!dir.remove(info.fileName()))
return false;
}
}
QDir parentDir(QFileInfo(dirPath).path());
return parentDir.rmdir(QFileInfo(dirPath).fileName());
}
This doesn't handle links and special files, btw.
The hard way. Copy every file individually.
Use QDir::entryList() to iterate over the content of a directory
Use QDir::cd() and QDir::cdUp() to go in and out of directories
Use QDir::mkdir() and QDir::mkpath() to create the new folders tree
and finally, use QFile::copy() to copy the actual files
This is basically petch's answer with a slight change due to it breaking for me in Qt 5.6 (this is the top question hit), so all credit goes to petch.
function
bool copyPath(QString sourceDir, QString destinationDir, bool overWriteDirectory)
{
QDir originDirectory(sourceDir);
if (! originDirectory.exists())
{
return false;
}
QDir destinationDirectory(destinationDir);
if(destinationDirectory.exists() && !overWriteDirectory)
{
return false;
}
else if(destinationDirectory.exists() && overWriteDirectory)
{
destinationDirectory.removeRecursively();
}
originDirectory.mkpath(destinationDir);
foreach (QString directoryName, originDirectory.entryList(QDir::Dirs | \
QDir::NoDotAndDotDot))
{
QString destinationPath = destinationDir + "/" + directoryName;
originDirectory.mkpath(destinationPath);
copyPath(sourceDir + "/" + directoryName, destinationPath, overWriteDirectory);
}
foreach (QString fileName, originDirectory.entryList(QDir::Files))
{
QFile::copy(sourceDir + "/" + fileName, destinationDir + "/" + fileName);
}
/*! Possible race-condition mitigation? */
QDir finalDestination(destinationDir);
finalDestination.refresh();
if(finalDestination.exists())
{
return true;
}
return false;
}
Use:
/*! Overwrite existing directories. */
bool directoryCopied = copyPath(sourceDirectory, destinationDirectory, true);
/*! Do not overwrite existing directories. */
bool directoryCopied = copyPath(sourceDirectory, destinationDirectory, false);
Try this:
bool copyDirectoryFiles(const QString &fromDir, const QString &toDir, bool coverFileIfExist)
{
QDir sourceDir(fromDir);
QDir targetDir(toDir);
if(!targetDir.exists()){ /* if directory don't exists, build it */
if(!targetDir.mkdir(targetDir.absolutePath()))
return false;
}
QFileInfoList fileInfoList = sourceDir.entryInfoList();
foreach(QFileInfo fileInfo, fileInfoList){
if(fileInfo.fileName() == "." || fileInfo.fileName() == "..")
continue;
if(fileInfo.isDir()){ /* if it is directory, copy recursively*/
if(!copyDirectoryFiles(fileInfo.filePath(),
targetDir.filePath(fileInfo.fileName()),
coverFileIfExist))
return false;
}
else{ /* if coverFileIfExist == true, remove old file first */
if(coverFileIfExist && targetDir.exists(fileInfo.fileName())){
targetDir.remove(fileInfo.fileName());
}
// files copy
if(!QFile::copy(fileInfo.filePath(),
targetDir.filePath(fileInfo.fileName()))){
return false;
}
}
}
return true;
}
I have made a library to manipulate files by a shell command style API. It supports a recursively copy of files and handled several more conditions.
https://github.com/benlau/qtshell#cp
Example
cp("-a", ":/*", "/target"); // copy all files from qrc resource to target path recursively
cp("tmp.txt", "/tmp");
cp("*.txt", "/tmp");
cp("/tmp/123.txt", "456.txt");
cp("-va","src/*", "/tmp");
cp("-a", ":resource","/target");
Since I had some trouble with App-Bundles on macOS, here's a solution with QDirIterator
void copyAndReplaceFolderContents(const QString &fromDir, const QString &toDir, bool copyAndRemove = false) {
QDirIterator it(fromDir, QDirIterator::Subdirectories);
QDir dir(fromDir);
const int absSourcePathLength = dir.absoluteFilePath(fromDir).length();
while (it.hasNext()){
it.next();
const auto fileInfo = it.fileInfo();
if(!fileInfo.isHidden()) { //filters dot and dotdot
const QString subPathStructure = fileInfo.absoluteFilePath().mid(absSourcePathLength);
const QString constructedAbsolutePath = toDir + subPathStructure;
if(fileInfo.isDir()){
//Create directory in target folder
dir.mkpath(constructedAbsolutePath);
} else if(fileInfo.isFile()) {
//Copy File to target directory
//Remove file at target location, if it exists. Otherwise QFile::copy will fail
QFile::remove(constructedAbsolutePath);
QFile::copy(fileInfo.absoluteFilePath(), constructedAbsolutePath);
}
}
}
if(copyAndRemove)
dir.removeRecursively();
}
If you are on a linux based system and the cp command exists and can be run, then you can use a QProcess to launch a bash:
auto copy = new QProcess(this);
copy->start(QStringLiteral("cp -rv %1 %2").arg(sourceFolder, destinationFolder));
copy->waitForFinished();
copy->close();
cp details:
-r means recursively
-v means it prints the successfully copied file
Note: if the copy operation is long, then you need to managed the UI freezing, as noted here
Assuming the target location is empty "no existing files or folders
with the same names" and you have no problem to use a Recursive
function!! to copy a directory recursively then the code will be something like this
void copy_all(QString dst_loc, QString src_loc)
{
QDir src(src_loc);
for(QFileInfo file_info : src.entryInfoList(QDir::AllEntries | QDir::NoDotAndDotDot)){
if(file_info.isDir()){
src.mkpath(dst_loc+'/'+file_info.fileName());
copy_all(dst_loc+'/'+file_info.fileName(),file_info.absoluteFilePath());
}
QFile::copy(file_info.absoluteFilePath(), dst_loc+'/'+file_info.fileName());
}
}
if you ever dealt with tree data structures and tried to create a Recursive function to do a "depth-first search" Alogorithm you will get a 85% similar algorithm, which Actually I got this idea from.
The second way, is by using a map data structure to hold the current
fileInfoList in a directory, and the corresponding state to show if
you have used this fileInfo or not yet. and you gather all
information firstly about sub directories and files from the source location.
And this is how most OS and other file managers do to copy data, by showing you the size of files to be copied, how many files and folders are going to be copied, and finally, if there is any conflict of files or folders with the same name before you even initiate copying "if you will do the same algorithm with the destination so that you can match filenames".
Good luck!.