I am writing an application using <Phonon/VideoWidget>.
I'd like to have two windows. One is the main window with controls for the video
And the other has the video itself. It will be displayed in another monitor. -fullscreen or not.
How can I make the video window - that can be moved or resizabled - with the video inside?
When not playing any video, the video window should display an image.
In the end I didnt use QStackedWidget, I extended Phonon::VideoWidget and made this class...
Heres the cpp:
MyVideoWidget::MyVideoWidget(QWidget *parent) : Phonon::VideoWidget(parent)
{
label = new QLabel(this);
label->setAutoFillBackground(true);
label->setBackgroundRole(QPalette::Light);
label->setScaledContents(true);
}
void MyVideoWidget::mouseDoubleClickEvent(QMouseEvent* event)
{
if(!this->isFullScreen())
this->enterFullScreen();
else
this->setFullScreen(false);
}
void MyVideoWidget::keyPressEvent(QKeyEvent* event)
{
if(event->key() == Qt::Key_Escape)
{
if(!this->isFullScreen())
this->enterFullScreen();
else
this->setFullScreen(false);
}
}
void MyVideoWidget::enterImageMode(QString imagePath)
{
QPixmap pmap;
pmap.fill(QColor(255, 255, 255));
if(!pmap.load(imagePath))
{
label->setText("Erro ao carregar imagem: "+imagePath);
if(!label->isVisible())
label->show();
return;
}
label->setPixmap(pmap);
if(!label->isVisible())
label->show();
repaint();
}
void MyVideoWidget::enterVideoMode()
{
label->hide();
}
void MyVideoWidget::resizeEvent(QResizeEvent* event)
{
Phonon::VideoWidget::resizeEvent(event);
label->setGeometry(this->geometry());
repaint();
}
MyVideoWidget::~MyVideoWidget()
{
}
Related
I have a small javafx application using scene builder which on a button click should read a string from COM port at regular intervals and update in a text field.
But now it only shows the last string if I use a for loop, and nothing if i put the code in infinite loop (That's my temporary requirement).
Can anyone help me so that at each read from COM port the new string is updated in the text field.
Here is the code I used for both the cases :
Note : In both cases in controller class, I'm getting perfect output on console.
public class Main extends Application
{
#Override
public void start(Stage primaryStage)
{
try
{
Parent root = FXMLLoader.load(getClass().getResource("test.fxml"));
Scene scene = new Scene(root);
//scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setTitle("test");
primaryStage.setScene(scene);
primaryStage.show();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void main(String[] args)
{
launch(args);
}
}
Here is the Controller class :
// In this case it shows only the last string in the text field.
public class Controller implements Initializable
{
#FXML
private Button sayHelloButton;
#FXML
private TextField helloField;
#Override
public void initialize(URL arg0, ResourceBundle arg1)
{
}
#FXML
public void printHello(ActionEvent event)
{
if(event.getSource() == sayHelloButton)
{
SerialPort serialPort = new SerialPort("COM22");
for(int i=0;i<5;i++)
{
try
{
if(!serialPort.isOpened())
{
serialPort.openPort();
serialPort.setParams(9600, 8, 1, 0);
}
String str = serialPort.readString(10,3000);
System.out.println(str);
helloField.clear();
helloField.setText(str);
}
catch(Exception e)
{
helloField.setText(e.toString());
}
}
}
}
}
Here is the method with infinite loop :
//this shows nothing in the text field
#FXML
public void printHello(ActionEvent event)
{
if(event.getSource() == sayHelloButton)
{
SerialPort serialPort = new SerialPort("COM22");
while(true)
{
try
{
if(!serialPort.isOpened())
{
serialPort.openPort();
serialPort.setParams(9600, 8, 1, 0);
}
String str = serialPort.readString(10,3000);
System.out.println(str);
helloField.clear();
helloField.setText(str);
}
catch(Exception e)
{
helloField.setText(e.toString());
}
}
}
}
There are a couple things happening here. In your first example, you state that the console output is correct but the TextField only shows the last result.
This is expected if the loop executes quickly. The TextField is being updated, but it happens so quickly that you can't see it until the loop ends and the last result is still being displayed. Even if you have a delay built into the loop, this could still block the UI from being updated until the loop is completed.
With your infinite loop, the issue is that the loop is being run on the JavaFX Application Thread (JFXAT). This blocks any updates to the GUI until the loop is finished, which is never is.
You will need to move the infinite loop to a new background thread. From there, you can update the GUI using the Platform.runLater() method.
SerialPort serialPort = new SerialPort("COM22");
new Thread(() -> {
while(true)
{
try
{
if(!serialPort.isOpened())
{
serialPort.openPort();
serialPort.setParams(9600, 8, 1, 0);
}
String str = serialPort.readString(10,3000);
System.out.println(str);
// Update the UI on the JavaFX Application Thread
Platform.runLater(() -> {
helloField.clear();
helloField.setText(str);
});
}
catch(Exception e)
{
Platform.runLater(() -> helloField.setText(e.toString()));
}
}
}).start();
This allows your UI to continually update as the background thread sends it new information.
I am writing a TicTacToe game in JavaFX. I've decided to make a board as 9 (3x3) buttons with changing text: "" (if empty) or "X" or "O". Everything is going ok beside one thing... I got stuck here:
public void game() {
while(keepPlaying) {
if(computerTurn) {;
computerMove();
}else {
while(waitForUser) {
//wait until any of 9 buttons is pushed!
}
}
if (checkResult()) {
keepPlaying = false;
}
computerTurn = !computerTurn;
}
}
How to wait for user pushing any of those 9 buttons and then continue with computer turn??
I need something like waiting for scanner input in console application, but this input must be one of 9 buttons...
I know that there are few "possible duplicates", but in fact those problems were solved using methods I can't use here, for example timer. Correct me if I am wrong.
Blocking the application thread in JavaFX should not be done since it freezes the UI. For this reason a loop like this is not well suited for a JavaFX application. Instead you should react to user input:
public void game() {
if (keepPlaying && computerTurn) {
computerMove();
if (checkResult()) {
keepPlaying = false;
}
computerTurn = false;
}
}
// button event handler
private void button(ActionEvent event) {
if (keepPlaying) {
Button source = (Button) event.getSource();
// probably the following 2 coordinates are computed from GridPane indices
int x = getX(source);
int y = getY(source);
// TODO: update state according to button pressed
if (checkResult()) {
keepPlaying = false;
} else {
computerMove();
if (checkResult()) {
keepPlaying = false;
}
}
}
}
Starting with javafx 9 there is a public API for "pausing" on the application thread however:
private static class GridCoordinates {
int x,y;
GridCoordinates (int x, int y) {
this.x = x;
this.y = y;
}
}
private final Object loopKey = new Object();
public void game() {
while(keepPlaying) {
if(computerTurn) {
computerMove();
} else {
// wait for call of Platform.exitNestedEventLoop​(loopKey, *)
GridCoordinates coord = (GridCoordinates) Platform.enterNestedEventLoop​(loopKey);
// TODO: update state
}
if (checkResult()) {
keepPlaying = false;
}
computerTurn = !computerTurn;
}
}
private void button(ActionEvent event) {
if (keepPlaying) {
Button source = (Button) event.getSource();
// probably the following 2 coordinates are computed from GridPane indices
int x = getX(source);
int y = getY(source);
Platform.exitNestedEventLoop​(loopKey, new GridCoordinates(x, y));
}
}
4 states are: hover, leave, focusIn, focusOut.
What i am doing now is creating a new class (MyButton) and promote QPushButton.
mybutton.cpp:
void MyButton::enterEvent(QEvent* e) {
emit hovered();
}
void MyButton::leaveEvent(QEvent* e) {
emit leaved();
}
void MyButton::focusInEvent(QFocusEvent* e) {
emit focused();
}
void MyButton::focusOutEvent(QFocusEvent* e) {
emit notfocused();
}
main.cpp:
connect(ui.button, SIGNAL(hovered()), this, SLOT(button_hover()));
connect(ui.button, SIGNAL(focused()), this, SLOT(button_focus()));
connect(ui.button, SIGNAL(leaved()), this, SLOT(button_leave()));
connect(ui.button, SIGNAL(notfocused()), this, SLOT(button_notfocus()));
void MyWindow::button_hover() {
this->ui.button->setStyleSheet("border-image:url(:/ptd/graphics/button_mouseover.png);");
}
void MyWindow::button_focus() {
this->ui.button->setStyleSheet("border-image:url(:/ptd/graphics/button_mouseover.png);");
}
void MyWindow::button_leave() {
this->ui.button->setStyleSheet("border-image:url(:/ptd/graphics/button_leave.png);");
}
void MyWindow::button_notfocus() {
this->ui.button->setStyleSheet("border-image:url(:/ptd/graphics/button_leave.png);");
}
I think that is too long. What I want to do is:
ui.button->setObjectName("Yes");
ui.button->setStyleSheet("QPushButton#Yes{border-image: url(:/ptd/graphics/button_leave.png);}"
"QPushButton#Yes:hover{border-image: url(:/ptd/graphics/button_mouseover.png);}");
which is shorter and we do not have to create a new class. But I just know the state hover in this case. How to set for the other 3 states?
I've derived a class from QQuickPaintedItem in which I want to handle the mousePressEvent and the mouseReleasEvent (and also the mouseMoveEvent but that is not my prolem now).
The mousePressEvent gets called properly everytime the left mouse button is pressed. But the mouseReleaseEvent gets only called after a double click. What I expected is to get the event everytime the button is released. How can I change this?
This is what I do:
MyView::MyView(QQuickItem *parent):
QQuickPaintedItem(parent)
{
setAcceptedMouseButtons(Qt::LeftButton);
}
void MyView::mousePressEvent(QMouseEvent *evt)
{
//gets called after every single mouse click
qDebug("mousePressEvent");
if(evt->button() == Qt::LeftButton)
{
//do something...
evt->accept();
}
else
{
evt->ignore();
}
QQuickPaintedItem::mousePressEvent(evt);
}
void MyView::mouseReleaseEvent(QMouseEvent *evt)
{
//gets only called when releasing the mouse button after a double click
qDebug("mouseReleaseEvent");
if(evt->button() == Qt::LeftButton)
{
//do something...
evt->accept();
}
else
{
evt->ignore();
}
QQuickPaintedItem::mouseReleaseEvent(evt);
}
So I finally found the solution!
Calling the base class implementation is a bad idea since the base class simply calls ignore() on the event. Here is the base class implementation:
void QWindow::mousePressEvent(QMouseEvent *ev)
{
ev->ignore();
}
void QWindow::mouseReleaseEvent(QMouseEvent *ev)
{
ev->ignore();
}
So this is how it works:
MyView::MyView(QQuickItem *parent):
QQuickPaintedItem(parent)
{
setAcceptedMouseButtons(Qt::LeftButton);
}
void MyView::mousePressEvent(QMouseEvent *evt)
{
//gets called after every single mouse click
qDebug("mousePressEvent");
if(evt->button() == Qt::LeftButton)
{
//do something...
evt->accept();
}
else
{
evt->ignore();
}
//DON'T DO THIS:
//QQuickPaintedItem::mousePressEvent(evt);
}
void MyView::mouseReleaseEvent(QMouseEvent *evt)
{
//now gets called with every mouse release since we don't call the base class any more
qDebug("mouseReleaseEvent");
if(evt->button() == Qt::LeftButton)
{
//do something...
evt->accept();
}
else
{
evt->ignore();
}
//DON'T DO THIS:
//QQuickPaintedItem::mouseReleaseEvent(evt);
}
Suppose there are checkboxes, options etc controls in a dialog box, how could I save the state of the dialog in Qt?
Should I use QSettings or something else?
Thanks.
I ran into the same problem.
Googling didn't help too much.
So in the end I wrote my own solution.
I've created a set of functions that read and write the state of each child control of a dialog at creation respectively destruction.
It is generic and can be used for any dialog.
It works like this:
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
QMoMSettings::readSettings(this);
}
Dialog::~Dialog()
{
QMoMSettings::writeSettings(this);
delete ui;
}
...
void QMoMSettings::readSettings(QWidget* window)
{
QSettings settings;
settings.beginGroup(window->objectName());
QVariant value = settings.value("pos");
if (!value.isNull())
{
window->move(settings.value("pos").toPoint());
window->resize(settings.value("size").toSize());
recurseRead(settings, window);
}
settings.endGroup();
}
void QMoMSettings::writeSettings(QWidget* window)
{
QSettings settings;
settings.beginGroup(window->objectName());
settings.setValue("pos", window->pos());
settings.setValue("size", window->size());
recurseWrite(settings, window);
settings.endGroup();
}
void QMoMSettings::recurseRead(QSettings& settings, QObject* object)
{
QCheckBox* checkbox = dynamic_cast<QCheckBox*>(object);
if (0 != checkbox)
{
checkbox->setChecked(settings.value(checkbox->objectName()).toBool());
}
QComboBox* combobox = dynamic_cast<QComboBox*>(object);
if (0 != combobox)
{
combobox->setCurrentIndex(settings.value(combobox->objectName()).toInt());
}
...
foreach(QObject* child, object->children())
{
recurseRead(settings, child);
}
}
void QMoMSettings::recurseWrite(QSettings& settings, QObject* object)
{
QCheckBox* checkbox = dynamic_cast<QCheckBox*>(object);
if (0 != checkbox)
{
settings.setValue(checkbox->objectName(), checkbox->isChecked());
}
QComboBox* combobox = dynamic_cast<QComboBox*>(object);
if (0 != combobox)
{
settings.setValue(combobox->objectName(), combobox->currentIndex());
}
...
foreach(QObject* child, object->children())
{
recurseWrite(settings, child);
}
}
Hope this helps someone after me.
QSettings will work fine for what you need, but you're essentially just serializing the options and reloading them at start up so there's plenty of documentation on doing it in Qt.