SIP Dialog Example

Sometimes it is necessary for a dialog to take the SIP into account, as the SIP may hide important input widgets. The SIP Dialog Example shows how a Dialog 对象， dialog , can be resized accordingly if the SIP is opened, by embedding the contents of dialog 在 QScrollArea .

对话框类定义

The Dialog 类是子类化的 QDialog that implements a public slot, desktopResized() , and a public function, reactToSIP() . Also, it holds a private instance of QRect , desktopGeometry .

class Dialog : public QDialog
{
    Q_OBJECT
public:
    Dialog();
    void reactToSIP();
private:
    QRect desktopGeometry;
public slots:
    void desktopResized(int screen);
};

对话框类实现

In the constructor of Dialog , we start by obtaining the available geometry of the screen with availableGeometry() . The parameter used is 0 to indicate that we require the primary screen.

Dialog::Dialog()
{
    desktopGeometry = QApplication::desktop()->availableGeometry(0);
    setWindowTitle(tr("SIP Dialog Example"));
    QScrollArea *scrollArea = new QScrollArea(this);
    QGroupBox *groupBox = new QGroupBox(scrollArea);
    groupBox->setTitle(tr("SIP Dialog Example"));
    QGridLayout *gridLayout = new QGridLayout(groupBox);
    groupBox->setLayout(gridLayout);

We set the window's title to "SIP Dialog Example" and declare a QScrollArea 对象， scrollArea . Next we instantiate a QGroupBox , groupBox ，采用 scrollArea as its parent. The title of groupBox is also set to "SIP Dialog Example". A QGridLayout 对象， gridLayout , is then used as groupBox 's layout.

创建 QLineEdit ， QLabel 和 QPushButton and we set the minimumWidth property to 220 pixels, respectively.

    QLineEdit* lineEdit = new QLineEdit(groupBox);
    lineEdit->setText(tr("Open and close the SIP"));
    lineEdit->setMinimumWidth(220);
    QLabel* label = new QLabel(groupBox);
    label->setText(tr("This dialog resizes if the SIP is opened"));
    label->setMinimumWidth(220);
    QPushButton* button = new QPushButton(groupBox);
    button->setText(tr("Close Dialog"));
    button->setMinimumWidth(220);

Also, all three widgets' text are set accordingly. The verticalSpacing property of gridLayout is set based on the height of desktopGeometry . This is to adapt to the different form factors of Windows Mobile. Then, we add our widgets to the layout.

    if (desktopGeometry.height() < 400)
        gridLayout->setVerticalSpacing(80);
    else
        gridLayout->setVerticalSpacing(150);
    gridLayout->addWidget(label);
    gridLayout->addWidget(lineEdit);
    gridLayout->addWidget(button);

The scrollArea 's widget is set to groupBox . We use a QHBoxLayout 对象， layout , to contain scrollArea 。 Dialog 's layout is set to layout and the scroll area's horizontal scroll bar is turned off.

    scrollArea->setWidget(groupBox);
    QHBoxLayout* layout = new QHBoxLayout();
    layout->addWidget(scrollArea);
    setLayout(layout);
    scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

The following signals are connected to their respective slots:

button 's pressed() signal to QApplication 's closeAllWindows() slot,
QDesktopWidget 's workAreaResized() signal to dialog 's desktopResized() 槽。

    connect(button, SIGNAL(clicked()),
        qApp, SLOT(closeAllWindows()));
    connect(QApplication::desktop(), SIGNAL(workAreaResized(int)),
        this, SLOT(desktopResized(int)));
}

The desktopResized() function accepts an integer, screen , corresponding to the screen's index. We only invoke reactToSIP() if screen is the primary screen (e.g. index = 0).

void Dialog::desktopResized(int screen)
{
    if (screen != 0)
        return;
    reactToSIP();
}

The reactToSIP() function resizes dialog accordingly if the desktop's available geometry changed vertically, as this change signifies that the SIP may have been opened or closed.

void Dialog::reactToSIP()
{
    QRect availableGeometry = QApplication::desktop()->availableGeometry(0);
    if (desktopGeometry != availableGeometry) {
        if (windowState() | Qt::WindowMaximized)
            setWindowState(windowState() & ~Qt::WindowMaximized);
        setGeometry(availableGeometry);
    }
    desktopGeometry = availableGeometry;
}

If the height has decreased, we unset the maximized window state. Otherwise, we set the maximized window state. Lastly, we update desktopGeometry to the desktop's available geometry.

The `main()` function

The main() function for the SIP Dialog example instantiates Dialog and invokes its exec() 函数。

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Dialog dialog;
    return dialog.exec();
}

注意： Although this example uses a dialog, the techniques used here apply to all top-level widgets respectively.

文件：

内容

SIP Dialog Example

对话框类定义

对话框类实现

The main() function

The `main()` function