automatically scroll parent QScrollArea when QgsCollapsibleGroupBox is expanded

Author: etiennesky

src/gui/qgscollapsiblegroupbox.cpp

@@ -24,6 +24,7 @@
 #include <QMouseEvent>
 #include <QStyleOptionGroupBox>
 #include <QSettings>
+#include <QScrollArea>
 
 QIcon QgsCollapsibleGroupBox::mCollapseIcon;
 QIcon QgsCollapsibleGroupBox::mExpandIcon;
@@ -52,7 +53,9 @@ void QgsCollapsibleGroupBox::init()
   mCollapsed = false;
   mSaveState = true;
   mInitFlat = false;
+  mScrollOnExpand = true;
   mShown = false;
+  mParentScrollArea = 0;
 
   // init icons
   if ( mCollapseIcon.isNull() )
@@ -87,6 +90,16 @@ void QgsCollapsibleGroupBox::showEvent( QShowEvent * event )
   // check if groupbox was set to flat in Designer or in code
   mInitFlat = isFlat();
 
+  // find parent QScrollArea - this might not work in complex layouts - should we look deeper?
+  if ( parent() && parent()->parent() )
+    mParentScrollArea = dynamic_cast<QScrollArea*>( parent()->parent()->parent() );
+  else
+    mParentScrollArea = 0;
+  if ( mParentScrollArea )
+    QgsDebugMsg( "found a QScrollArea parent: " + mParentScrollArea->objectName() );
+  else
+    QgsDebugMsg( "did not find a QScrollArea parent" );
+
   loadState();
 
   updateStyle();
@@ -278,6 +291,13 @@ void QgsCollapsibleGroupBox::setCollapsed( bool collapse )
   setMaximumHeight( collapse ? titleRect().bottom() + 6 : 16777215 );
   mCollapseButton->setIcon( collapse ? mExpandIcon : mCollapseIcon );
 
+  // if expanding and is in a QScrollArea, scroll down to make entire widget visible
+  if ( mScrollOnExpand && !collapse && mParentScrollArea )
+  {
+    // process events so entire widget is shown
+    QApplication::processEvents();
+    mParentScrollArea->ensureWidgetVisible( this );
+  }
   emit collapsedStateChanged( this );
 }
 

src/gui/qgscollapsiblegroupbox.h

@@ -28,6 +28,7 @@
 #include <QGroupBox>
 
 class QToolButton;
+class QScrollArea;
 
 class GUI_EXPORT QgsCollapsibleGroupBox : public QGroupBox
 {
@@ -37,17 +38,21 @@ class GUI_EXPORT QgsCollapsibleGroupBox : public QGroupBox
     QgsCollapsibleGroupBox( QWidget *parent = 0 );
     QgsCollapsibleGroupBox( const QString &title, QWidget *parent = 0 );
     ~QgsCollapsibleGroupBox();
+
     bool isCollapsed() const { return mCollapsed; }
     void setCollapsed( bool collapse );
+
+    //! set this to false to not save/restore check and collapse state
     void setSaveState( bool save ) { mSaveState = save; }
+    //! set this to false to not automatically scroll parent QScrollArea to this widget's contents when expanded
+    void setScrollOnExpand( bool scroll ) { mScrollOnExpand = scroll; }
 
   signals:
     void collapsedStateChanged( QWidget* );
 
   public slots:
     void checkToggled( bool ckd );
     void toggleCollapsed();
-    void updateStyle();
 
   protected slots:
     void loadState();
@@ -57,13 +62,16 @@ class GUI_EXPORT QgsCollapsibleGroupBox : public QGroupBox
     void init();
     void showEvent( QShowEvent *event );
     void mouseReleaseEvent( QMouseEvent *event );
+    void updateStyle();
     QRect titleRect() const;
     QString saveKey() const;
 
     bool mCollapsed;
     bool mSaveState;
     bool mInitFlat;
+    bool mScrollOnExpand;
     bool mShown;
+    QScrollArea* mParentScrollArea;
     QToolButton* mCollapseButton;
 
     static QIcon mCollapseIcon;

src/gui/qgsrasterlayersaveasdialog.cpp

@@ -106,11 +106,6 @@ QgsRasterLayerSaveAsDialog::QgsRasterLayerSaveAsDialog( QgsRasterLayer* rasterLa
   {
     okButton->setEnabled( false );
   }
-
-  // this should scroll down to make widget visible, but it's not happening
-  // (at least part of it is visible)...
-  connect( mCreateOptionsGroupBox, SIGNAL( collapsedStateChanged( QWidget* ) ),
-           this, SLOT( groupBoxExpanded( QWidget* ) ) );
 }
 
 void QgsRasterLayerSaveAsDialog::setValidators()
@@ -529,12 +524,6 @@ void QgsRasterLayerSaveAsDialog::on_mRawModeRadioButton_toggled( bool checked )
   mNoDataGroupBox->setEnabled( checked && mDataProvider->bandCount() == 1 );
 }
 
-void QgsRasterLayerSaveAsDialog::groupBoxExpanded( QWidget * widget )
-{
-  if ( !mCreateOptionsGroupBox->isCollapsed() )
-    mScrollArea->ensureWidgetVisible( widget );
-}
-
 void QgsRasterLayerSaveAsDialog::on_mAddNoDataManuallyToolButton_clicked()
 {
   addNoDataRow( std::numeric_limits<double>::quiet_NaN(), std::numeric_limits<double>::quiet_NaN() );

src/gui/qgsrasterlayersaveasdialog.h

@@ -92,7 +92,6 @@ class GUI_EXPORT QgsRasterLayerSaveAsDialog: public QDialog, private Ui::QgsRast
 
     void on_mCrsComboBox_currentIndexChanged( int ) { crsChanged(); }
 
-    void groupBoxExpanded( QWidget * widget );
     void on_mAddNoDataManuallyToolButton_clicked();
     void on_mLoadTransparentNoDataToolButton_clicked();
     void on_mRemoveSelectedNoDataToolButton_clicked();