Bugfixes: don't select dirs and don't crash on write settings

Only select files when archiving pics from filemanager. While at it, I
noticed a crash on close when no item is selected in PicturesWidget. So
check if MappingData is valid on writing settings. Best way is
MappingData::isValid(), and for that I needed a explicit constructor.

1 files changed, 2 insertions, 3 deletions

diff --git a/mappingtreewidget.cpp b/mappingtreewidget.cpp
index e9d0c93..fd3ebe6 100644
--- a/mappingtreewidget.cpp
+++ b/mappingtreewidget.cpp
@@ -94,13 +94,12 @@ MappingTreeWidget::MappingTreeWidget(QWidget *parent) : QWidget(parent){
 }
 
 MappingData MappingTreeWidget::selectedItem() const {
-    MappingData retval = { -1, -1, -1, QString(), QList<QStringList>() };
     QModelIndex sel = selected();
     if(!sel.isValid()){
-        return retval;
+        return MappingData();
     }
     QModelIndex real = mProxy->mapToSource(sel);
-        return mModel->mappingDataFromIndex(real);
+    return mModel->mappingDataFromIndex(real);
 }
 
 void MappingTreeWidget::addChild(){