Add recent file handling to SDI/MDI and remove the recentfiles example.

The existing recentfiles example was basically a clone of the SDI
example with a "Recent" menu added. Assuming it is better to have
it all in one place, the functionality is merged into the existing
SDI/MDI examples.

- Implement recently opened files handling using a submenu and a
  QSettings array in the SDI/MDI examples.
- Remove recentfiles example.

Change-Id: Id5a1ab9fa1c2e6b9ec81309cfe74cf86f450392a
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>

3 files changed, 124 insertions, 10 deletions

diff --git a/examples/widgets/mainwindows/mdi/main.cpp b/examples/widgets/mainwindows/mdi/main.cpp
index 5976c85c1c..f02285d1cf 100644
--- a/examples/widgets/mainwindows/mdi/main.cpp
+++ b/examples/widgets/mainwindows/mdi/main.cpp
@@ -49,6 +49,8 @@ int main(int argc, char *argv[])
     Q_INIT_RESOURCE(mdi);
 
     QApplication app(argc, argv);
+    QCoreApplication::setApplicationName("MDI Example");
+    QCoreApplication::setOrganizationName("QtProject");
     QCoreApplication::setApplicationVersion(QT_VERSION_STR);
     QCommandLineParser parser;
     parser.setApplicationDescription("Qt MDI Example");
diff --git a/examples/widgets/mainwindows/mdi/mainwindow.cpp b/examples/widgets/mainwindows/mdi/mainwindow.cpp
index 4dada5ce70..35136c81c4 100644
--- a/examples/widgets/mainwindows/mdi/mainwindow.cpp
+++ b/examples/widgets/mainwindows/mdi/mainwindow.cpp
@@ -82,19 +82,24 @@ void MainWindow::newFile()
 
 void MainWindow::open()
 {
-    QString fileName = QFileDialog::getOpenFileName(this);
-    if (!fileName.isEmpty()) {
-        if (QMdiSubWindow *existing = findMdiChild(fileName)) {
-            mdiArea->setActiveSubWindow(existing);
-            return;
-        }
+    const QString fileName = QFileDialog::getOpenFileName(this);
+    if (!fileName.isEmpty())
+        openFile(fileName);
+}
 
-        if (openFile(fileName))
-            statusBar()->showMessage(tr("File loaded"), 2000);
+bool MainWindow::openFile(const QString &fileName)
+{
+    if (QMdiSubWindow *existing = findMdiChild(fileName)) {
+        mdiArea->setActiveSubWindow(existing);
+        return true;
     }
+    const bool succeeded = loadFile(fileName);
+    if (succeeded)
+        statusBar()->showMessage(tr("File loaded"), 2000);
+    return succeeded;
 }
 
-bool MainWindow::openFile(const QString &fileName)
+bool MainWindow::loadFile(const QString &fileName)
 {
     MdiChild *child = createMdiChild();
     const bool succeeded = child->loadFile(fileName);
@@ -102,9 +107,87 @@ bool MainWindow::openFile(const QString &fileName)
         child->show();
     else
         child->close();
+    MainWindow::prependToRecentFiles(fileName);
     return succeeded;
 }
 
+static inline QString recentFilesKey() { return QStringLiteral("recentFileList"); }
+static inline QString fileKey() { return QStringLiteral("file"); }
+
+static QStringList readRecentFiles(QSettings &settings)
+{
+    QStringList result;
+    const int count = settings.beginReadArray(recentFilesKey());
+    for (int i = 0; i < count; ++i) {
+        settings.setArrayIndex(i);
+        result.append(settings.value(fileKey()).toString());
+    }
+    settings.endArray();
+    return result;
+}
+
+static void writeRecentFiles(const QStringList &files, QSettings &settings)
+{
+    const int count = files.size();
+    settings.beginWriteArray(recentFilesKey());
+    for (int i = 0; i < count; ++i) {
+        settings.setArrayIndex(i);
+        settings.setValue(fileKey(), files.at(i));
+    }
+    settings.endArray();
+}
+
+bool MainWindow::hasRecentFiles()
+{
+    QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
+    const int count = settings.beginReadArray(recentFilesKey());
+    settings.endArray();
+    return count > 0;
+}
+
+void MainWindow::prependToRecentFiles(const QString &fileName)
+{
+    QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
+
+    const QStringList oldRecentFiles = readRecentFiles(settings);
+    QStringList recentFiles = oldRecentFiles;
+    recentFiles.removeAll(fileName);
+    recentFiles.prepend(fileName);
+    if (oldRecentFiles != recentFiles)
+        writeRecentFiles(recentFiles, settings);
+
+    setRecentFilesVisible(!recentFiles.isEmpty());
+}
+
+void MainWindow::setRecentFilesVisible(bool visible)
+{
+    recentFileSubMenuAct->setVisible(visible);
+    recentFileSeparator->setVisible(visible);
+}
+
+void MainWindow::updateRecentFileActions()
+{
+    QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
+
+    const QStringList recentFiles = readRecentFiles(settings);
+    const int count = qMin(int(MaxRecentFiles), recentFiles.size());
+    int i = 0;
+    for ( ; i < count; ++i) {
+        const QString fileName = QFileInfo(recentFiles.at(i)).fileName();
+        recentFileActs[i]->setText(tr("&%1 %2").arg(i + 1).arg(fileName));
+        recentFileActs[i]->setData(recentFiles.at(i));
+        recentFileActs[i]->setVisible(true);
+    }
+    for ( ; i < MaxRecentFiles; ++i)
+        recentFileActs[i]->setVisible(false);
+}
+
+void MainWindow::openRecentFile()
+{
+    if (const QAction *action = qobject_cast<const QAction *>(sender()))
+        openFile(action->data().toString());
+}
+
 void MainWindow::save()
 {
     if (activeMdiChild() && activeMdiChild()->save())
@@ -113,8 +196,11 @@ void MainWindow::save()
 
 void MainWindow::saveAs()
 {
-    if (activeMdiChild() && activeMdiChild()->saveAs())
+    MdiChild *child = activeMdiChild();
+    if (child && child->saveAs()) {
         statusBar()->showMessage(tr("File saved"), 2000);
+        MainWindow::prependToRecentFiles(child->currentFile());
+    }
 }
 
 #ifndef QT_NO_CLIPBOARD
@@ -262,8 +348,23 @@ void MainWindow::createActions()
 
     fileMenu->addSeparator();
 
+    QMenu *recentMenu = fileMenu->addMenu(tr("Recent..."));
+    connect(recentMenu, &QMenu::aboutToShow, this, &MainWindow::updateRecentFileActions);
+    recentFileSubMenuAct = recentMenu->menuAction();
+
+    for (int i = 0; i < MaxRecentFiles; ++i) {
+        recentFileActs[i] = recentMenu->addAction(QString(), this, &MainWindow::openRecentFile);
+        recentFileActs[i]->setVisible(false);
+    }
+
+    recentFileSeparator = fileMenu->addSeparator();
+
+    setRecentFilesVisible(MainWindow::hasRecentFiles());
+
     fileMenu->addAction(tr("Switch layout direction"), this, &MainWindow::switchLayoutDirection);
 
+    fileMenu->addSeparator();
+
 //! [0]
     const QIcon exitIcon = QIcon::fromTheme("application-exit");
     QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), qApp, &QApplication::closeAllWindows);
diff --git a/examples/widgets/mainwindows/mdi/mainwindow.h b/examples/widgets/mainwindows/mdi/mainwindow.h
index bdc2a6a09d..3ac60282fd 100644
--- a/examples/widgets/mainwindows/mdi/mainwindow.h
+++ b/examples/widgets/mainwindows/mdi/mainwindow.h
@@ -68,6 +68,8 @@ private slots:
     void open();
     void save();
     void saveAs();
+    void updateRecentFileActions();
+    void openRecentFile();
 #ifndef QT_NO_CLIPBOARD
     void cut();
     void copy();
@@ -80,10 +82,16 @@ private slots:
     void switchLayoutDirection();
 
 private:
+    enum { MaxRecentFiles = 5 };
+
     void createActions();
     void createStatusBar();
     void readSettings();
     void writeSettings();
+    bool loadFile(const QString &fileName);
+    static bool hasRecentFiles();
+    void prependToRecentFiles(const QString &fileName);
+    void setRecentFilesVisible(bool visible);
     MdiChild *activeMdiChild() const;
     QMdiSubWindow *findMdiChild(const QString &fileName) const;
 
@@ -93,6 +101,9 @@ private:
     QAction *newAct;
     QAction *saveAct;
     QAction *saveAsAct;
+    QAction *recentFileActs[MaxRecentFiles];
+    QAction *recentFileSeparator;
+    QAction *recentFileSubMenuAct;
 #ifndef QT_NO_CLIPBOARD
     QAction *cutAct;
     QAction *copyAct;