[FEATURE] Show field values in autocompleter in form filter mode

This adds a new gui widget QgsFieldValuesLineEdit which includes an autocompleter populated with current field values. The autocompleter is nicely updated in the background so that the gui remains nice and responsive, even if there's millions of records in the associated table. It's now used as a search widget for text fields, so can be seen in the browser window if you set the filter to a text field, or if you launch the form based select/filter by selecting a layer and pressing F3.
qgis · Dec 22, 2016 · 0bfc9bb · 0bfc9bb · m-kuhn · Dec 22, 2016
1 parent e27822b
commit 0bfc9bb
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Showing 7 changed files with 430 additions and 3 deletions.
diff --git a/python/gui/gui.sip b/python/gui/gui.sip
@@ -75,6 +75,7 @@
 %Include qgsfieldmodel.sip
 %Include qgsfieldproxymodel.sip
 %Include qgsfieldvalidator.sip
+%Include qgsfieldvalueslineedit.sip
 %Include qgsfiledropedit.sip
 %Include qgsfilewidget.sip
 %Include qgsfiledownloader.sip

diff --git a/python/gui/qgsfieldvalueslineedit.sip b/python/gui/qgsfieldvalueslineedit.sip
@@ -0,0 +1,59 @@
+/** \class QgsFieldValuesLineEdit
+ * \ingroup gui
+ * A line edit with an autocompleter which takes unique values from a vector layer's fields.
+ * The autocompleter is populated from the vector layer in the background to ensure responsive
+ * interaction with the widget.
+ * \note added in QGIS 3.0
+ */
+class QgsFieldValuesLineEdit: QgsFilterLineEdit
+{
+%TypeHeaderCode
+#include <qgsfieldvalueslineedit.h>
+%End
+  public:
+
+    /** Constructor for QgsFieldValuesLineEdit
+     * @param parent parent widget
+     */
+    QgsFieldValuesLineEdit( QWidget *parent /TransferThis/ = nullptr );
+
+    virtual ~QgsFieldValuesLineEdit();
+
+    /** Sets the layer containing the field that values will be shown from.
+     * @param layer vector layer
+     * @see layer()
+     * @see setAttributeIndex()
+     */
+    void setLayer( QgsVectorLayer* layer );
+
+    /** Returns the layer containing the field that values will be shown from.
+     * @see setLayer()
+     * @see attributeIndex()
+     */
+    QgsVectorLayer* layer() const;
+
+    /** Sets the attribute index for the field containing values to show in the widget.
+     * @param index index of attribute
+     * @see attributeIndex()
+     * @see setLayer()
+     */
+    void setAttributeIndex( int index );
+
+    /** Returns the attribute index for the field containing values shown in the widget.
+     * @see setAttributeIndex()
+     * @see layer()
+     */
+    int attributeIndex() const;
+
+  signals:
+
+    /** Emitted when the layer associated with the widget changes.
+     * @param layer vector layer
+     */
+    void layerChanged( QgsVectorLayer* layer );
+
+    /** Emitted when the field associated with the widget changes.
+     * @param index new attribute index for field
+     */
+    void attributeIndexChanged( int index );
+};
diff --git a/src/gui/CMakeLists.txt b/src/gui/CMakeLists.txt
@@ -223,6 +223,7 @@ SET(QGIS_GUI_SRCS
   qgsfieldmodel.cpp
   qgsfieldproxymodel.cpp
   qgsfieldvalidator.cpp
+  qgsfieldvalueslineedit.cpp
   qgsfiledropedit.cpp
   qgsfilewidget.cpp
   qgsfilterlineedit.cpp
@@ -391,6 +392,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsfieldmodel.h
   qgsfieldproxymodel.h
   qgsfieldvalidator.h
+  qgsfieldvalueslineedit.h
   qgsfiledropedit.h
   qgsfilewidget.h
   qgsfilterlineedit.h

diff --git a/src/gui/editorwidgets/qgsdefaultsearchwidgetwrapper.cpp b/src/gui/editorwidgets/qgsdefaultsearchwidgetwrapper.cpp
@@ -18,6 +18,7 @@
 #include "qgsfields.h"
 #include "qgsfieldvalidator.h"
 #include "qgsexpression.h"
+#include "qgsfieldvalueslineedit.h"
 #include <QSettings>
 #include <QHBoxLayout>
 
@@ -255,10 +256,20 @@ void QgsDefaultSearchWidgetWrapper::initWidget( QWidget* widget )
   mContainer->setLayout( new QHBoxLayout() );
   mContainer->layout()->setMargin( 0 );
   mContainer->layout()->setContentsMargins( 0, 0, 0, 0 );
-  mLineEdit = new QgsFilterLineEdit();
+  QVariant::Type fldType = layer()->fields().at( mFieldIdx ).type();
+
+  if ( fldType == QVariant::String )
+  {
+    mLineEdit = new QgsFieldValuesLineEdit();
+    static_cast< QgsFieldValuesLineEdit* >( mLineEdit )->setLayer( layer() );
+    static_cast< QgsFieldValuesLineEdit* >( mLineEdit )->setAttributeIndex( mFieldIdx );
+  }
+  else
+  {
+    mLineEdit = new QgsFilterLineEdit();
+  }
   mContainer->layout()->addWidget( mLineEdit );
 
-  QVariant::Type fldType = layer()->fields().at( mFieldIdx ).type();
   if ( fldType == QVariant::String )
   {
     mCheckbox = new QCheckBox( QStringLiteral( "Case sensitive" ) );

diff --git a/src/gui/editorwidgets/qgsdefaultsearchwidgetwrapper.h b/src/gui/editorwidgets/qgsdefaultsearchwidgetwrapper.h
@@ -17,7 +17,7 @@
 #define QGSDEFAULTSEARCHWIDGETWRAPPER_H
 
 #include "qgssearchwidgetwrapper.h"
-#include <qgsfilterlineedit.h>
+#include "qgsfilterlineedit.h"
 
 #include <QCheckBox>
 

diff --git a/src/gui/qgsfieldvalueslineedit.cpp b/src/gui/qgsfieldvalueslineedit.cpp
@@ -0,0 +1,137 @@
+/***************************************************************************
+    qgsfieldvalueslineedit.cpp
+     -------------------------
+    Date                 : 20-08-2016
+    Copyright            : (C) 2016 by Nyall Dawson
+    Email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsfieldvalueslineedit.h"
+#include "qgsvectorlayer.h"
+#include "qgsfloatingwidget.h"
+#include <QCompleter>
+#include <QStringListModel>
+#include <QTimer>
+#include <QHBoxLayout>
+
+QgsFieldValuesLineEdit::QgsFieldValuesLineEdit( QWidget *parent )
+    : QgsFilterLineEdit( parent )
+    , mLayer( nullptr )
+    , mAttributeIndex( -1 )
+    , mUpdateRequested( false )
+    , mGatherer( nullptr )
+{
+  QCompleter* c = new QCompleter( this );
+  c->setCaseSensitivity( Qt::CaseInsensitive );
+  c->setFilterMode( Qt::MatchContains );
+  setCompleter( c );
+  connect( this, &QgsFieldValuesLineEdit::textEdited, this, &QgsFieldValuesLineEdit::requestCompleterUpdate );
+  mShowPopupTimer.setSingleShot( true );
+  mShowPopupTimer.setInterval( 100 );
+  connect( &mShowPopupTimer, &QTimer::timeout, this, &QgsFieldValuesLineEdit::triggerCompleterUpdate );
+}
+
+QgsFieldValuesLineEdit::~QgsFieldValuesLineEdit()
+{
+  if ( mGatherer )
+  {
+    mGatherer->stop();
+    mGatherer->wait(); // mGatherer is deleted when wait completes
+  }
+}
+
+void QgsFieldValuesLineEdit::setLayer( QgsVectorLayer* layer )
+{
+  if ( mLayer == layer )
+    return;
+
+  mLayer = layer;
+  emit layerChanged( layer );
+}
+
+void QgsFieldValuesLineEdit::setAttributeIndex( int index )
+{
+  if ( mAttributeIndex == index )
+    return;
+
+  mAttributeIndex = index;
+  emit attributeIndexChanged( index );
+}
+
+void QgsFieldValuesLineEdit::requestCompleterUpdate()
+{
+  mUpdateRequested = true;
+  mShowPopupTimer.start();
+}
+
+void QgsFieldValuesLineEdit::triggerCompleterUpdate()
+{
+  mShowPopupTimer.stop();
+  QString currentText = text();
+
+  if ( currentText.isEmpty() )
+  {
+    if ( mGatherer )
+      mGatherer->stop();
+    return;
+  }
+
+  updateCompletionList( currentText );
+}
+
+void QgsFieldValuesLineEdit::updateCompletionList( const QString &text )
+{
+  if ( text.isEmpty() )
+  {
+    if ( mGatherer )
+      mGatherer->stop();
+    return;
+  }
+
+  mUpdateRequested = true;
+  if ( mGatherer )
+  {
+    mRequestedCompletionText = text;
+    mGatherer->stop();
+    return;
+  }
+
+  mGatherer = new QgsFieldValuesLineEditValuesGatherer( mLayer, mAttributeIndex );
+  mGatherer->setSubstring( text );
+
+  connect( mGatherer, &QgsFieldValuesLineEditValuesGatherer::collectedValues, this, &QgsFieldValuesLineEdit::updateCompleter );
+  connect( mGatherer, &QgsFieldValuesLineEditValuesGatherer::finished, this, &QgsFieldValuesLineEdit::gathererThreadFinished );
+
+  mGatherer->start();
+}
+
+void QgsFieldValuesLineEdit::gathererThreadFinished()
+{
+  bool wasCancelled = mGatherer->wasCancelled();
+
+  delete mGatherer;
+  mGatherer = nullptr;
+
+  if ( wasCancelled )
+  {
+    QString text = mRequestedCompletionText;
+    mRequestedCompletionText.clear();
+    updateCompletionList( text );
+    return;
+  }
+}
+
+void QgsFieldValuesLineEdit::updateCompleter( const QStringList& values )
+{
+  mUpdateRequested = false;
+  completer()->setModel( new QStringListModel( values ) );
+  completer()->complete();
+}
+