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Polish the imageviewer example.

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- Remove unneeded member variables.
- Use member initialization in the constructor.
- Use new connection syntax in createActions()
  to assemble the menu there, removing the createMenus()
  function.
- Fix coding style issue (braces)
- Avoid empty label showing up by setting the scroll
  area invisible until an image is loaded.
- Set a new image only if image read succeeds.
- Add status bar with information message.

Task-number: QTBUG-46848
Change-Id: I32d5af70d8eb71ec16dd58a0b98c32eb2bd988d7
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
This commit is contained in:
Friedemann Kleint 2015-07-09 13:25:16 +02:00
parent b349289fa0
commit 5549ba4fa5
3 changed files with 37 additions and 74 deletions
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11
examples/widgets/doc/src/imageviewer.qdoc
View File

@ -287,7 +287,8 @@
\snippet widgets/imageviewer/imageviewer.cpp 18
In the private \c createAction() function, we create the
actions providing the application features.
actions providing the application features and populate
a menu with them.
We assign a short-cut key to each action and connect them to the
appropriate slots. We only enable the \c openAct and \c exitAct at
@ -295,16 +296,10 @@
been loaded into the application. In addition we make the \c
fitToWindowAct \l {QAction::checkable}{checkable}.
\snippet widgets/imageviewer/imageviewer.cpp 19
\snippet widgets/imageviewer/imageviewer.cpp 20
In the private \c createMenu() function, we add the previously
created actions to the \uicontrol File, \uicontrol View and \uicontrol Help menus.
The QMenu class provides a menu widget for use in menu bars,
context menus, and other popup menus. The QMenuBar class provides
a horizontal menu bar that consists of a list of pull-down menu
items. So at the end we put the menus in the \c {ImageViewer}'s
items. So we put the menus in the \c {ImageViewer}'s
menu bar which we retrieve with the QMainWindow::menuBar()
function.

92
examples/widgets/widgets/imageviewer/imageviewer.cpp
View File

@ -47,19 +47,20 @@
//! [0]
ImageViewer::ImageViewer()
: imageLabel(new QLabel)
, scrollArea(new QScrollArea)
, scaleFactor(1)
{
imageLabel = new QLabel;
imageLabel->setBackgroundRole(QPalette::Base);
imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
imageLabel->setScaledContents(true);
scrollArea = new QScrollArea;
scrollArea->setBackgroundRole(QPalette::Dark);
scrollArea->setWidget(imageLabel);
scrollArea->setVisible(false);
setCentralWidget(scrollArea);
createActions();
createMenus();
resize(QGuiApplication::primaryScreen()->availableSize() * 3 / 5);
}
@ -74,10 +75,8 @@ bool ImageViewer::loadFile(const QString &fileName)
const QImage image = reader.read();
if (image.isNull()) {
QMessageBox::information(this, QGuiApplication::applicationDisplayName(),
tr("Cannot load %1.").arg(QDir::toNativeSeparators(fileName)));
setWindowFilePath(QString());
imageLabel->setPixmap(QPixmap());
imageLabel->adjustSize();
tr("Cannot load %1: %2")
.arg(QDir::toNativeSeparators(fileName)), reader.errorString());
return false;
}
//! [2] //! [3]
@ -85,6 +84,7 @@ bool ImageViewer::loadFile(const QString &fileName)
//! [3] //! [4]
scaleFactor = 1.0;
scrollArea->setVisible(true);
printAct->setEnabled(true);
fitToWindowAct->setEnabled(true);
updateActions();
@ -93,6 +93,10 @@ bool ImageViewer::loadFile(const QString &fileName)
imageLabel->adjustSize();
setWindowFilePath(fileName);
const QString message = tr("Opened \"%1\", %2x%3, Depth: %4")
.arg(QDir::toNativeSeparators(fileName)).arg(image.width()).arg(image.height()).arg(image.depth());
statusBar()->showMessage(message);
return true;
}
@ -167,9 +171,8 @@ void ImageViewer::fitToWindow()
{
bool fitToWindow = fitToWindowAct->isChecked();
scrollArea->setWidgetResizable(fitToWindow);
if (!fitToWindow) {
if (!fitToWindow)
normalSize();
}
updateActions();
}
//! [14]
@ -199,75 +202,48 @@ void ImageViewer::about()
void ImageViewer::createActions()
//! [17] //! [18]
{
openAct = new QAction(tr("&Open..."), this);
openAct->setShortcut(tr("Ctrl+O"));
connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
printAct = new QAction(tr("&Print..."), this);
printAct->setShortcut(tr("Ctrl+P"));
QAction *openAct = fileMenu->addAction(tr("&Open..."), this, &ImageViewer::open);
openAct->setShortcut(QKeySequence::Open);
printAct = fileMenu->addAction(tr("&Print..."), this, &ImageViewer::print);
printAct->setShortcut(QKeySequence::Print);
printAct->setEnabled(false);
connect(printAct, SIGNAL(triggered()), this, SLOT(print()));
exitAct = new QAction(tr("E&xit"), this);
fileMenu->addSeparator();
QAction *exitAct = fileMenu->addAction(tr("E&xit"), this, &QWidget::close);
exitAct->setShortcut(tr("Ctrl+Q"));
connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
zoomInAct = new QAction(tr("Zoom &In (25%)"), this);
zoomInAct->setShortcut(tr("Ctrl++"));
QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
zoomInAct = viewMenu->addAction(tr("Zoom &In (25%)"), this, &ImageViewer::zoomIn);
zoomInAct->setShortcut(QKeySequence::ZoomIn);
zoomInAct->setEnabled(false);
connect(zoomInAct, SIGNAL(triggered()), this, SLOT(zoomIn()));
zoomOutAct = new QAction(tr("Zoom &Out (25%)"), this);
zoomOutAct->setShortcut(tr("Ctrl+-"));
zoomOutAct = viewMenu->addAction(tr("Zoom &Out (25%)"), this, &ImageViewer::zoomOut);
zoomOutAct->setShortcut(QKeySequence::ZoomOut);
zoomOutAct->setEnabled(false);
connect(zoomOutAct, SIGNAL(triggered()), this, SLOT(zoomOut()));
normalSizeAct = new QAction(tr("&Normal Size"), this);
normalSizeAct = viewMenu->addAction(tr("&Normal Size"), this, &ImageViewer::normalSize);
normalSizeAct->setShortcut(tr("Ctrl+S"));
normalSizeAct->setEnabled(false);
connect(normalSizeAct, SIGNAL(triggered()), this, SLOT(normalSize()));
fitToWindowAct = new QAction(tr("&Fit to Window"), this);
viewMenu->addSeparator();
fitToWindowAct = viewMenu->addAction(tr("&Fit to Window"), this, &ImageViewer::fitToWindow);
fitToWindowAct->setEnabled(false);
fitToWindowAct->setCheckable(true);
fitToWindowAct->setShortcut(tr("Ctrl+F"));
connect(fitToWindowAct, SIGNAL(triggered()), this, SLOT(fitToWindow()));
aboutAct = new QAction(tr("&About"), this);
connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
aboutQtAct = new QAction(tr("About &Qt"), this);
connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
helpMenu->addAction(tr("&About"), this, &ImageViewer::about);
helpMenu->addAction(tr("About &Qt"), &QApplication::aboutQt);
}
//! [18]
//! [19]
void ImageViewer::createMenus()
//! [19] //! [20]
{
fileMenu = new QMenu(tr("&File"), this);
fileMenu->addAction(openAct);
fileMenu->addAction(printAct);
fileMenu->addSeparator();
fileMenu->addAction(exitAct);
viewMenu = new QMenu(tr("&View"), this);
viewMenu->addAction(zoomInAct);
viewMenu->addAction(zoomOutAct);
viewMenu->addAction(normalSizeAct);
viewMenu->addSeparator();
viewMenu->addAction(fitToWindowAct);
helpMenu = new QMenu(tr("&Help"), this);
helpMenu->addAction(aboutAct);
helpMenu->addAction(aboutQtAct);
menuBar()->addMenu(fileMenu);
menuBar()->addMenu(viewMenu);
menuBar()->addMenu(helpMenu);
}
//! [20]
//! [21]
void ImageViewer::updateActions()
//! [21] //! [22]

8
examples/widgets/widgets/imageviewer/imageviewer.h
View File

@ -87,19 +87,11 @@ private:
QPrinter printer;
#endif
QAction *openAct;
QAction *printAct;
QAction *exitAct;
QAction *zoomInAct;
QAction *zoomOutAct;
QAction *normalSizeAct;
QAction *fitToWindowAct;
QAction *aboutAct;
QAction *aboutQtAct;
QMenu *fileMenu;
QMenu *viewMenu;
QMenu *helpMenu;
};
//! [0]