[Attachment widget] Respect relative paths settings by drag&drop

src/gui/qgsfilewidget.cpp

@@ -62,6 +62,7 @@ QgsFileWidget::QgsFileWidget( QWidget *parent )
   mLineEdit->setDragEnabled( true );
   mLineEdit->setToolTip( tr( "Full path to the file(s), including name and extension" ) );
   connect( mLineEdit, &QLineEdit::textChanged, this, &QgsFileWidget::textEdited );
+  connect( mLineEdit, &QgsFileDropEdit::fileDropped, this, &QgsFileWidget::fileDropped );
   mLayout->addWidget( mLineEdit );
 
   mFileWidgetButton = new QToolButton( this );
@@ -178,6 +179,13 @@ void QgsFileWidget::editLink()
   updateLayout();
 }
 
+void QgsFileWidget::fileDropped( const QString &filePath )
+{
+  setSelectedFileNames( QStringList() << filePath );
+  mLineEdit->selectAll();
+  mLineEdit->setFocus( Qt::MouseFocusReason );
+}
+
 bool QgsFileWidget::useLink() const
 {
   return mUseLink;
@@ -585,12 +593,11 @@ void QgsFileDropEdit::dropEvent( QDropEvent *event )
   QString filePath = acceptableFilePath( event );
   if ( !filePath.isEmpty() )
   {
-    setText( filePath );
-    selectAll();
-    setFocus( Qt::MouseFocusReason );
     event->acceptProposedAction();
-    setHighlighted( false );
+    emit fileDropped( filePath );
   }
+
+  setHighlighted( false );
 }
 
 ///@endcond

src/gui/qgsfilewidget.h

@@ -206,6 +206,7 @@ class GUI_EXPORT QgsFileWidget : public QWidget
     void openFileDialog();
     void textEdited( const QString &path );
     void editLink();
+    void fileDropped( const QString &filePath );
 
   private:
     void updateLayout();
@@ -266,6 +267,13 @@ class GUI_EXPORT QgsFileDropEdit: public QgsHighlightableLineEdit
 
     void setFilters( const QString &filters );
 
+  signals:
+
+    /**
+     * Emitted when the file \a filePath is droppen onto the line edit.
+     */
+    void fileDropped( const QString &filePath );
+
   protected:
 
     void dragEnterEvent( QDragEnterEvent *event ) override;