Merge pull request #10076 from Chocobo1/pr_9756

Prevent flickering preview dialog

src/gui/previewselectdialog.cpp

@@ -35,6 +35,7 @@
 #include <QStandardItemModel>
 #include <QTableView>
 
+#include "base/bittorrent/torrenthandle.h"
 #include "base/preferences.h"
 #include "base/utils/fs.h"
 #include "base/utils/misc.h"
@@ -93,10 +94,6 @@ PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHan
         }
     }
 
-    if (m_previewListModel->rowCount() == 0) {
-        QMessageBox::critical(this->parentWidget(), tr("Preview impossible"), tr("Sorry, we can't preview this file"));
-        close();
-    }
     connect(this, SIGNAL(readyToPreviewFile(QString)), parent, SLOT(previewFile(QString)));
     m_previewListModel->sort(NAME);
     previewList->header()->setSortIndicator(0, Qt::AscendingOrder);

src/gui/previewselectdialog.h

@@ -31,12 +31,15 @@
 
 #include <QDialog>
 
-#include "base/bittorrent/torrenthandle.h"
 #include "base/settingvalue.h"
 #include "ui_previewselectdialog.h"
 
 class QStandardItemModel;
 
+namespace BitTorrent
+{
+    class TorrentHandle;
+}
 class PreviewListDelegate;
 
 class PreviewSelectDialog : public QDialog, private Ui::preview

src/gui/transferlistwidget.cpp

@@ -48,6 +48,7 @@
 #include "base/preferences.h"
 #include "base/torrentfilter.h"
 #include "base/utils/fs.h"
+#include "base/utils/misc.h"
 #include "base/utils/string.h"
 #include "autoexpandabledialog.h"
 #include "deletionconfirmationdialog.h"
@@ -198,6 +199,19 @@ namespace
             setDefaultWidget(new MenuCheckBox(text, onToggle, initialState));
         }
     };
+
+    bool torrentContainsPreviewableFiles(const BitTorrent::TorrentHandle *const torrent)
+    {
+        if (!torrent->hasMetadata())
+            return false;
+
+        for (int i = 0; i < torrent->filesCount(); ++i) {
+            if (Utils::Misc::isPreviewable(Utils::Fs::fileExtension(torrent->fileName(i))))
+                return true;
+        }
+
+        return false;
+    }
 }
 
 TransferListWidget::TransferListWidget(QWidget *parent, MainWindow *mainWindow)
@@ -589,8 +603,10 @@ void TransferListWidget::openSelectedTorrentsFolder() const
 void TransferListWidget::previewSelectedTorrents()
 {
     for (BitTorrent::TorrentHandle *const torrent : asConst(getSelectedTorrents())) {
-        if (torrent->hasMetadata())
+        if (torrentContainsPreviewableFiles(torrent))
             new PreviewSelectDialog(this, torrent);
+        else
+            QMessageBox::critical(this, tr("Unable to preview"), tr("The selected torrent does not contain previewable files"));
     }
 }