Qt MouseTracking in QTableWidget

I want to enable mouseTracking in a QTableWidget using Qt4.7. Usually this should be straight forward with setMouseTracking(true). This worked on other widgets, but QTableWidget resists it. Is there anything special I have to deal with in order to activate mouseTracking?

Although i'm actually doing more complex stuff i could gain confidence that its not enabled by printing out QMouseEvent.x() in mouseMoveEvent. thanks so far :)

Here is what I tried:

    QGridLayout * layout = new QGridLayout(this);
    SCTableWidget * aTable = new SCTableWidget(tableRows, tableCols, this);

    QTableWidgetItem * newItem;
    for(int i = 0; i<(3); i++) {
        for(int j = 0; j<(17); j++) {
            newItem = new QTableWidgetItem(QString::number(tableData[i][j]));
            aTable->setItem(i,j, newItem);
        }
    }

// First try
    aTable->setMouseTr开发者_Go百科acking(true);

//Second try. Main Window further down.
    MainWindow::instance->enableMouseTracking(aTable->children());
    MainWindow::instance->enableMouseTracking(aTable->viewport()->children());


// Third try
    aTable->viewport()->setMouseTracking(true);

    layout->addWidget(aTable, 0, 0, 1, 2);

The second try contains a method that is implemented in MainWindow which looks like this:

void
MainWindow::enableMouseTracking(const QObjectList & pChildren)
{
  foreach(QObject * obj, pChildren)
  {
    QWidget * w = qobject_cast<QWidget *>(obj);

    if(w)
    {
      w->setMouseTracking(true);
      enableMouseTracking(w->children());
    }
  }
}

switching on mouse tracking for QTableWidget->viewport() usually works. Are you also catching mouse events for the QTableWidget->viewport() widget? Pls check if an example below would work fine for you:

test.h:

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

    bool eventFilter(QObject *obj, QEvent *event);

private:
    Ui::MainWindow *ui;
    QTableWidget *table;
};

test.cpp:

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    table = new QTableWidget(5, 10, this);
    table->setGeometry(10, 20, 300, 200);

    for (int row=0; row<5; ++row)
        for (int column=0; column<10; ++column)
            table->setItem(row, column, new QTableWidgetItem(tr("%1").arg((row+1)*(column+1))));

    table->setMouseTracking(true);
    table->viewport()->setMouseTracking(true);
    table->installEventFilter(this);
    table->viewport()->installEventFilter(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
    if (obj == table)
    {
        if (event->type() == QEvent::MouseButtonPress)
            qDebug() << "table mouse press event";
        else if (event->type() == QEvent::MouseMove)
            qDebug() << "table mouse moveevent";
    }
    else if (obj == table->viewport())
    {
        if (event->type() == QEvent::MouseButtonPress)
            qDebug() << "table->viewport mouse press event";
        else if (event->type() == QEvent::MouseMove)
            qDebug() << "table->viewport mouse moveevent";
    }
    return QMainWindow::eventFilter(obj, event);
}

hope this helps, regards

By default, the mouse events are disabled because QAbstractItemView implements the mousePressEvent, mouseReleaseEvent, etc functions, and QTableWidget doesn't implement them at all, this means the mouse messages are blocked by the functions in QAbstractItemView.

So one very easy way to resolve this issue is to subclass the QTableWidget class, and provide the mouse signals by yourself, it should be very easy, just try it!

This worked for me:

    aTable->setMouseTracking(true);
    aTable->viewport()->setMouseTracking(true);