Improve mime type filters in QFileDialog

This patch improves the handling of mime type filters in QFileDialog.

The main change is in selectMimeTypeFilter(), which was just falling back
unconditionally on selectNameFilter(). Instead, mime type filters should
have an higher priority than name filters.

This patch also adds a new selectedMimeTypeFilter() method, which is used in the unit test.

Change-Id: Ice8bb08f5ff46e4a942d539f6001424eca878f74
Reviewed-by: David Faure <david.faure@kdab.com>

3 files changed, 43 insertions, 3 deletions

diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index 8058dee567..5bfb7553a5 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -1461,6 +1461,19 @@ void QFileDialog::selectNameFilter(const QString &filter)
 }
 
 /*!
+ * \since 5.9
+ * \return The mimetype of the file that the user selected in the file dialog.
+ */
+QString QFileDialog::selectedMimeTypeFilter() const
+{
+    Q_D(const QFileDialog);
+    if (!d->usingWidgets())
+        return d->selectedMimeTypeFilter_sys();
+
+    return d->options->initiallySelectedMimeTypeFilter();
+}
+
+/*!
     \since 4.4
 
     Returns the filter that the user selected in the file dialog.
@@ -1579,9 +1592,19 @@ QStringList QFileDialog::mimeTypeFilters() const
 */
 void QFileDialog::selectMimeTypeFilter(const QString &filter)
 {
-    const QString text = nameFilterForMime(filter);
-    if (!text.isEmpty())
-        selectNameFilter(text);
+    Q_D(QFileDialog);
+    d->options->setInitiallySelectedMimeTypeFilter(filter);
+
+    const QString filterForMime = nameFilterForMime(filter);
+
+    if (!d->usingWidgets()) {
+        d->selectMimeTypeFilter_sys(filter);
+        if (d->selectedMimeTypeFilter_sys().isEmpty() && !filterForMime.isEmpty()) {
+            selectNameFilter(filterForMime);
+        }
+    } else if (!filterForMime.isEmpty()) {
+        selectNameFilter(filterForMime);
+    }
 }
 
 #endif // QT_NO_MIMETYPE
diff --git a/src/widgets/dialogs/qfiledialog.h b/src/widgets/dialogs/qfiledialog.h
index c2ab0b3918..7959eebd7b 100644
--- a/src/widgets/dialogs/qfiledialog.h
+++ b/src/widgets/dialogs/qfiledialog.h
@@ -125,6 +125,7 @@ public:
     void setNameFilters(const QStringList &filters);
     QStringList nameFilters() const;
     void selectNameFilter(const QString &filter);
+    QString selectedMimeTypeFilter() const;
     QString selectedNameFilter() const;
 
 #ifndef QT_NO_MIMETYPE
diff --git a/src/widgets/dialogs/qfiledialog_p.h b/src/widgets/dialogs/qfiledialog_p.h
index afebad4457..b665b54a9b 100644
--- a/src/widgets/dialogs/qfiledialog_p.h
+++ b/src/widgets/dialogs/qfiledialog_p.h
@@ -258,6 +258,8 @@ public:
     void selectFile_sys(const QUrl &filename);
     QList<QUrl> selectedFiles_sys() const;
     void setFilter_sys();
+    void selectMimeTypeFilter_sys(const QString &filter);
+    QString selectedMimeTypeFilter_sys() const;
     void selectNameFilter_sys(const QString &filter);
     QString selectedNameFilter_sys() const;
     //////////////////////////////////////////////
@@ -400,6 +402,20 @@ inline void QFileDialogPrivate::setFilter_sys()
         helper->setFilter();
 }
 
+inline void QFileDialogPrivate::selectMimeTypeFilter_sys(const QString &filter)
+{
+    if (QPlatformFileDialogHelper *helper = platformFileDialogHelper())
+        helper->selectMimeTypeFilter(filter);
+}
+
+QString QFileDialogPrivate::selectedMimeTypeFilter_sys() const
+{
+    if (QPlatformFileDialogHelper *helper = platformFileDialogHelper())
+        return helper->selectedMimeTypeFilter();
+
+    return QString();
+}
+
 inline void QFileDialogPrivate::selectNameFilter_sys(const QString &filter)
 {
     if (QPlatformFileDialogHelper *helper = platformFileDialogHelper())