When I have changeEvent(QEvent* event) with receive type event->type() == QEvent::LanguageChange, how can I get information about what the new language is in my app?
Qt don't have any object to represent application langugae. So you should implement it yorself.
Usually changeEvent(QEvent* event) with type QEvent::LanguageChange was caused by installTranslator(QTranslator*) so you should know witch langugae you loaded to translator and store it locally.
You can compare the translated string with its known translations:
void changeEvent(QEvent *event)
{
if (event->type() == QEvent::LanguageChange) {
QString translated = QCoreApplication::translate("some context", "Button");
if (translated == "Button")
// language is English
else if (translated == "Кнопка")
// language is Russian
...
}
}
Related
I needed to translate my english UI in french, so I did all the necessary with .ts and .qm files, load it in the QTranslator class, and install it to the QApplication:
//in the InterfaceWidget constructor:
QTranslator myappTranslator;
bool loaded = myappTranslator.load("myApp_" + QLocale::system().name());
qDebug() << "Is translation file loaded?" << loaded; // RETURNS TRUE
QApplication::installTranslator(&myappTranslator);
ui.setupUi(this);
ui.retranslateUi(this); //works, it translates the UI
Later, I create and attach to the InterfaceWidget another Widget (in a tab) called ConfigurationTabUI :
m_ConfigurationTabUI = new ConfigurationTabUI(ui.configTab);
The corresponding UI is also translated to french, correctly.
And here is my problem: in the ConfigurationTabUI's methods, it doesn't work when I try to translate a simple QString:
void ConfigurationTabUI::on_ValidButton_clicked(){
QString msg(ConfigurationTabUI::tr("message to translate"));
qDebug() << "translated string: " << msg; // NOT TRANSLATED
}
I really have no clue why...
Thanks for your help.
Note: I Use Qt5.2 and I double checked that the .ts file contains the right translated string.
Ok, I found the problem, it's just a dumb oversight:
QTranslator is created on the stack and not dynamically (on the heap), so the object is destroyed at the end of the method.
As a result, it translates the UI because the object is still there but later, when a slot is called, nothing get translated.
Here is my code:
//in the InterfaceWidget constructor:
QTranslator* myappTranslator = new QTranslator(QApplication::instance());
bool loaded = myappTranslator->load("myApp_" + QLocale::system().name());
qDebug() << "Is translation file loaded?" << loaded; // RETURNS TRUE
QApplication::installTranslator(myappTranslator);
ui.setupUi(this);
and in ConfigurationTabUI (which inherits from QWidget):
void ConfigurationTabUI::changeEvent(QEvent *e)
{
if (e->type() == QEvent::LanguageChange) {
ui.retranslateUi(this);
reset(); //my method to reload some data in UI
} else
QWidget::changeEvent(e);
}
I am working on a Qt project consisting in a QMainWindow and multiple Qt and non-Qt classes. Many of them use QStrings with tr() that are translated with Qt Linguist. The language change (QTranslator load & install/QTranslator load & remove) is triggered by QActions in the app's menu.
I have read the official Qt documentation concerning dynamic translation, and it basically suggests the following overload:
void MainWindow::changeEvent(QEvent *event)
{
if (event->type() == QEvent::LanguageChange) {
titleLabel->setText(tr("Document Title"));
... // all my tr() QStrings here
okPushButton->setText(tr("&OK"));
} else
QWidget::changeEvent(event);
}
The problem I am facing is that the QStrings to translate are many (58 in QMainWindow alone), and several are filled at runtime as well, through user interaction; e. g. myFunction(a,b) below is called through a QPushButton:
void MainWindow::myFunction(MyClassA a, MyClassB b)
{
...
if(b.myCondition() == 0)
{
...
// below is the problem
myLabel->setText(myLabel->text() + QString("\n" + a->getName() + tr(" gagne ") + exp + tr(" points d'expérience")));
}
else
{
myLabel->setText(QString(tr("something else")));
}
...
}
So I hardly see how I can include this type of QString in the changeEvent() method above. What about the classes outside of MainWindow, which also have QStrings to translate but are not QWidget (so no changeEvent overload possible) ?
I have read that there's another way to use this method, with a UI form:
void MainWindow::changeEvent(QEvent* event)
{
if (event->type() == QEvent::LanguageChange)
{
ui.retranslateUi(this);
}
...
}
But this involves that I am using a UI form in my project, which I am not doing (all widgets are created in code).
I tried to export my MainWindow in a UI form, but when I try to include the generated header into the project, I get the following error:
ui_fenetreprincipale.h:32: error: qmainwindowlayout.h: No such file or directory
Thank you by advance for any suggestion to select the best way to translate my application.
Organize your code so that all the setting of translatable strings is done in one method in each class.
eg give every class that has translatable strings a setTrs() method that actually sets the strings.
class A
{
void setTrs()
{
okPushButton->setText(tr("&OK"));
}
}
//--------------
class B
{
int _trCond;
void myFunction(MyClassA a, MyClassB b)
{
_trCond = b.myCondition();
setTrs();
}
void setTrs()
{
if(_trCond == 0)
myLabel->setText(myLabel->text() + QString("\n" + a->getName() + tr(" gagne ") + exp + tr(" points d'expérience")));
else
myLabel->setText(QString(tr("something else")));
}
Then whenever the language for the application changes (eg connect to a menu entry selection, or MainWindow::event() or however the required language can change), you have to manually call the setTrs method of each of these objects
eg
void MainWindow::changeEvent(QEvent *event)
{
if (event->type() == QEvent::LanguageChange)
{
setTrs();
objA.setTrs();
objB.setTrs();
}
}
Even more elegant would be to store the objects in a QList and just iterate through it calling the setTrs method on each element in turn
I had the same problem, menus not translating, fixed completely by creating and installing the QTranslator...
QScopedPointer<QApplication> app(new QApplication(argc, argv));
QTranslator myappTranslator;
myappTranslator.load(QString("Languages/de"))
app->installTranslator(&myappTranslator);
...before creating and showing the main window...
MainWindow *mainWin;
mainWin = new MainWindow(&splash);
mainWin->show();
I am trying to "cancel" key codes in QTextEdit or QPlainTextEdit. When I say cancel, what I mean is, I want to turn the "entered" character into "nothing" depending on the key entered. Example: if the user hits "a" or "b" on the keyboard, I would not want to have "a" or "b" displayed / entered into the text, instead, the input would be ignored and turned into nothing / won't be processed.
With C++ Builder, you have a KeyDown_Event and a "Key" parameter. Once you detect the entered key code, if you don't like it, you can set the "Key" parameter to 0, so you set "Key = 0" and the key stroke would not be displayed. How do I achieve the same thing in Qt?
Let me explain with code:
if (e->key() == 67)
// do not send "c" to the QTextEdit (In C++ Bullder, you would do Key = 0)
if (e->key() == 65)
// do not send "a" to the QTextEdit (In C++ Bullder, you would do Key = 0)
How do I do this in Qt?
I tired doing e->setAccepted(false) and e->Ignore() but it made no difference. I think by the time e->ignore() is executed, the "char" is already inserted into the text box. With C++ Builder, you can intercept this with the KeyDown event and cancel it. I can't seem to find a way with Qt.
Thx
Similar to void QObject::installEventFilter ( QObject * filterObj ) example:
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
setupUi(this);
textEdit->installEventFilter(this);
}
bool MainWindow::eventFilter(QObject *watched, QEvent *event)
{
if (watched == textEdit && event->type() == QEvent::KeyPress) {
QKeyEvent *e = static_cast < QKeyEvent * >(event);
if (e->key() == Qt::Key_A) {
return true;
}
}
return QMainWindow::eventFilter(watched, event);
}
UPDATE
As IInspectable noticed, this won't help you with filtering Ctrl+C/Ctrl+V method. If you need these either, you'll need to connect to QTextEdit::textChanged signal and updated the text manually. Something like this:
static QString oldString;
QString s = textEdit->toPlainText();
if (s == oldString)
return;
int pos = textEdit->textCursor().position();
s.remove('a', Qt::CaseInsensitive);
oldString = s;
textEdit.setPlainText(s);
QTextCursor cursor = textEdit->textCursor();
cursor.setPosition(pos);
textEdit->setTextCursor(cursor);
I have wrote an application in Qt/c++ on OSX. When quitting the app, I'm catching the closeevent to display dialog box
void MainUI::closeEvent (QCloseEvent *event)
{
if( DeviceUnplugged == false) {
ExitDialog = new DialogExit;
ExitDialog->exec();
if(ExitDialog->result() == QDialog::Accepted) {
m_device.CloseDevice();
event->accept();
}
else {
event->ignore();
}
}
}
The dialog box is correctly displayed when closing using the red cross or using the menu "quit".
but when I'm closing the app using the right click on the icon in the dock, the dialog box appears twice the close event is called twice.
Any idea why ?
Yes, I think it is normal for Mac, at least I had this in my Qt application, too (only on Mac).
I used the following workaround:
void MainUI::closeEvent (QCloseEvent *event)
{
if (m_closing)
{
event->accept();
return;
}
if( DeviceUnplugged == false) {
ExitDialog = new DialogExit;
ExitDialog->exec();
if(ExitDialog->result() == QDialog::Accepted) {
m_device.CloseDevice();
m_closing = true;
event->accept();
}
else {
event->ignore();
}
}
}
By default, boolean variable m_closing should be initialized by false of course in your class. This way second time nothing will be done (processing will be skipped). This worked for me.
Looks like this is a QT bug:
See: https://bugreports.qt.io/browse/QTBUG-43344
Also had this problem when using qt-5.6_4 ,
In my case it happened when using CMD+Q but didn't happen when using the red x button.
Used a similar patch.
I avoided accept or ignore since this is a bug and I don't think we should "talk to it" :-)
Instead I simply return when called more then once.
static int numCalled = 0;
if (numCalled++ >= 1)
return;
In my app, i have several QDialog forms.
when i install and change translation of my app. MainWindow has been affected but all other dialogs didn't change to new Language.so,
how can i change all forms lang at runtime(dynamic)?
Please help me
void MainWindow::SetUILang()
{
QTranslator qtTranslator;
qtTranslator.load(QString("tr_fa"), "./Lang");
qApp->installTranslator(&qtTranslator);
ui->retranslateUi(this);
}
If you dynamically change the language on your application, a changeEvent of type QEvent::LanguageChange is emitted. You'll have to catch that and reset your texts everywhere (using the tr function)>
void myclass::changeEvent(QEvent *event) {
if (event->type() == QEvent::LanguageChange) {
// Set all texts
}
else {
QWidget::changeEvent(event);
}
}