AttributeForm: Create a dummy button box for intercepting ok clicks

when the ok button is hidden and the accept was actually triggered
by something else. This allows to continue using custom validation
logic without changes.
Fixes #8885

Author: m-kuhn

src/gui/attributetable/qgsdualview.cpp

@@ -37,6 +37,7 @@ QgsDualView::QgsDualView( QWidget* parent )
     , mEditorContext()
     , mMasterModel( NULL )
     , mAttributeDialog( NULL )
+    , mLayerCache( NULL )
     , mProgressDlg( NULL )
     , mFeatureSelectionManager( NULL )
 {
@@ -190,14 +191,14 @@ void QgsDualView::columnBoxInit()
 
 void QgsDualView::hideEvent( QHideEvent* event )
 {
-  saveEditChanges();
-  QStackedWidget::hideEvent( event );
+  if ( saveEditChanges() )
+    QStackedWidget::hideEvent( event );
 }
 
 void QgsDualView::focusOutEvent( QFocusEvent* event )
 {
-  saveEditChanges();
-  QStackedWidget::focusOutEvent( event );
+  if ( saveEditChanges() )
+    QStackedWidget::focusOutEvent( event );
 }
 
 void QgsDualView::setView( QgsDualView::ViewMode view )
@@ -257,35 +258,52 @@ void QgsDualView::initModels( QgsMapCanvas* mapCanvas, const QgsFeatureRequest&
 
 void QgsDualView::on_mFeatureList_currentEditSelectionChanged( const QgsFeature &feat )
 {
+  // Invalid feature? Strange: bail out
   if ( !feat.isValid() )
     return;
 
+  // We already show the feature in question: bail out
+  if ( mAttributeDialog && mAttributeDialog->feature()
+       && mAttributeDialog->feature()->id() == feat.id() )
+    return;
+
+  bool dontChange = false;
+
   // Backup old dialog and delete only after creating the new dialog, so we can "hot-swap" the contained QgsFeature
   QgsAttributeDialog* oldDialog = mAttributeDialog;
 
   if ( mAttributeDialog && mAttributeDialog->dialog() )
   {
-    saveEditChanges();
-    mAttributeEditorLayout->removeWidget( mAttributeDialog->dialog() );
+    if ( saveEditChanges() )
+      mAttributeEditorLayout->removeWidget( mAttributeDialog->dialog() );
+    else
+      dontChange = true;
   }
 
-  mAttributeDialog = new QgsAttributeDialog( mLayerCache->layer(), new QgsFeature( feat ), true, this, false, mEditorContext );
-  mAttributeEditorLayout->addWidget( mAttributeDialog->dialog() );
-  mAttributeDialog->dialog()->setVisible( true );
+  if ( !dontChange )
+  {
+    mAttributeDialog = new QgsAttributeDialog( mLayerCache->layer(), new QgsFeature( feat ), true, this, false, mEditorContext );
+    mAttributeEditorLayout->addWidget( mAttributeDialog->dialog() );
+    mAttributeDialog->dialog()->setVisible( true );
 
-  delete oldDialog;
+    delete oldDialog;
+  }
+  else
+  {
+    setCurrentEditSelection( QgsFeatureIds() << oldDialog->feature()->id() );
+  }
 }
 
 void QgsDualView::setCurrentEditSelection( const QgsFeatureIds& fids )
 {
   mFeatureList->setEditSelection( fids );
 }
 
-void QgsDualView::saveEditChanges()
+bool QgsDualView::saveEditChanges()
 {
   if ( mAttributeDialog && mAttributeDialog->dialog() )
   {
-    if ( mLayerCache->layer() && mLayerCache->layer()->isEditable() )
+    if ( mAttributeDialog->editable() )
     {
       // Get the current (unedited) feature
       QgsFeature srcFeat;
@@ -294,29 +312,47 @@ void QgsDualView::saveEditChanges()
       QgsAttributes src = srcFeat.attributes();
 
       // Let the dialog write the edited widget values to it's feature
-      mAttributeDialog->accept();
-      // Get the edited feature
-      const QgsAttributes &dst = mAttributeDialog->feature()->attributes();
-
-      if ( src.count() != dst.count() )
+      QDialogButtonBox* buttonBox = mAttributeDialog->dialog()->findChild<QDialogButtonBox*>();
+      if ( buttonBox && buttonBox->button( QDialogButtonBox::Ok ) )
       {
-        // bail out
-        return;
+        QPushButton* okBtn = buttonBox->button( QDialogButtonBox::Ok );
+        okBtn->click();
+      }
+      else
+      {
+        mAttributeDialog->accept();
       }
 
-      mLayerCache->layer()->beginEditCommand( tr( "Attributes changed" ) );
-
-      for ( int i = 0; i < dst.count(); ++i )
+      if ( mAttributeDialog->dialog()->result() == QDialog::Accepted )
       {
-        if ( dst[i] != src[i] )
+        // Get the edited feature
+        const QgsAttributes &dst = mAttributeDialog->feature()->attributes();
+
+        if ( src.count() != dst.count() )
         {
-          mLayerCache->layer()->changeAttributeValue( fid, i, dst[i] );
+          // bail out
+          return false;
         }
-      }
 
-      mLayerCache->layer()->endEditCommand();
+        mLayerCache->layer()->beginEditCommand( tr( "Attributes changed" ) );
+
+        for ( int i = 0; i < dst.count(); ++i )
+        {
+          if ( dst[i] != src[i] )
+          {
+            mLayerCache->layer()->changeAttributeValue( fid, i, dst[i] );
+          }
+        }
+
+        mLayerCache->layer()->endEditCommand();
+      }
+      else
+      {
+        return false;
+      }
     }
   }
+  return true;
 }
 
 void QgsDualView::previewExpressionBuilder()

src/gui/attributetable/qgsdualview.h

@@ -156,8 +156,11 @@ class GUI_EXPORT QgsDualView : public QStackedWidget, private Ui::QgsDualViewBas
 
     /**
      * @brief saveEditChanges
+     *
+     * @return true if the saving was ok. false is possible due to connected
+     *         validation logic.
      */
-    void saveEditChanges();
+    bool saveEditChanges();
 
     /**
      * Update the shown feature if an attribute changed

src/gui/attributetable/qgsfeaturelistview.cpp

@@ -97,6 +97,16 @@ QString QgsFeatureListView::parserErrorString()
   return mModel->parserErrorString();
 }
 
+QgsFeatureIds QgsFeatureListView::currentEditSelection()
+{
+  QgsFeatureIds selection;
+  Q_FOREACH( QModelIndex idx, mCurrentEditSelectionModel->selectedIndexes() )
+  {
+    selection << idx.data( QgsAttributeTableModel::FeatureIdRole ).value<QgsFeatureId>();
+  }
+  return selection;
+}
+
 void QgsFeatureListView::mousePressEvent( QMouseEvent *event )
 {
   QPoint pos = event->pos();

src/gui/attributetable/qgsfeaturelistview.h

@@ -100,6 +100,13 @@ class GUI_EXPORT QgsFeatureListView : public QListView
      */
     QString parserErrorString();
 
+    /**
+     * Get the currentEditSelection
+     *
+     * @return A list of edited feature ids
+     */
+    QgsFeatureIds currentEditSelection();
+
   protected:
     virtual void mouseMoveEvent( QMouseEvent *event );
     virtual void mousePressEvent( QMouseEvent *event );

src/gui/qgsattributedialog.cpp

@@ -418,6 +418,8 @@ void QgsAttributeDialog::init()
     }
   }
 
+  mEditable = mLayer->isEditable();
+
   if ( mDialog )
   {
     if ( mDialog->objectName().isEmpty() )
@@ -451,6 +453,16 @@ void QgsAttributeDialog::init()
   {
     if ( buttonBox )
     {
+      // Add dummy buttons
+      if ( mLayer->isEditable() )
+      {
+        buttonBox->clear();
+
+        buttonBox->setStandardButtons( QDialogButtonBox::Ok | QDialogButtonBox::Cancel );
+        connect( buttonBox, SIGNAL( accepted() ), mDialog, SLOT( accept() ) );
+        connect( buttonBox, SIGNAL( accepted() ), this, SLOT( accept() ) );
+      }
+
       buttonBox->setVisible( false );
     }
   }

src/gui/qgsattributedialog.h

@@ -80,6 +80,13 @@ class GUI_EXPORT QgsAttributeDialog : public QObject
 
     QgsFeature* feature() { return mFeature; }
 
+    /**
+     * Is this dialog editable?
+     *
+     * @return returns true, if this dialog was created in an editable manner.
+     */
+    bool editable() { return mEditable; }
+
   public slots:
     void accept();
 
@@ -106,6 +113,9 @@ class GUI_EXPORT QgsAttributeDialog : public QObject
     bool mShowDialogButtons;
     QString mReturnvarname;
 
+    // true if this dialog is editable
+    bool mEditable;
+
     static int sFormCounter;
     static QString sSettingsPath;
 };