From 8190930bb1152fd2bcfe2b4d093c875367ff30db Mon Sep 17 00:00:00 2001
From: Martin Dobias <wonder.sk@gmail.com>
Date: Sat, 13 Jan 2018 20:54:01 +0100
Subject: [PATCH] Show filter query in the indicator's tooltip

---
 src/app/qgslayertreeviewfilterindicator.cpp | 54 ++++++++++++++++++---
 src/app/qgslayertreeviewfilterindicator.h   |  7 ++-
 2 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/src/app/qgslayertreeviewfilterindicator.cpp b/src/app/qgslayertreeviewfilterindicator.cpp
index ed2eccb2f03..cda409fcda0 100644
--- a/src/app/qgslayertreeviewfilterindicator.cpp
+++ b/src/app/qgslayertreeviewfilterindicator.cpp
@@ -26,10 +26,7 @@ QgsLayerTreeViewFilterIndicatorManager::QgsLayerTreeViewFilterIndicatorManager(
   : QObject( view )
   , mLayerTreeView( view )
 {
-  mIndicator = new QgsLayerTreeViewIndicator( this );
-  mIndicator->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionFilter2.svg" ) ) );
-  mIndicator->setToolTip( "Filtered" );
-  connect( mIndicator, &QgsLayerTreeViewIndicator::clicked, this, &QgsLayerTreeViewFilterIndicatorManager::onIndicatorClicked );
+  mIcon = QgsApplication::getThemeIcon( QStringLiteral( "/mActionFilter2.svg" ) );
 
   QgsLayerTree *tree = mLayerTreeView->layerTreeModel()->rootGroup();
   onAddedChildren( tree, 0, tree->children().count() - 1 );
@@ -154,12 +151,57 @@ void QgsLayerTreeViewFilterIndicatorManager::onIndicatorClicked( const QModelInd
     vlayer->dataProvider()->setSubsetString( qb.sql() );
 }
 
+QgsLayerTreeViewIndicator *QgsLayerTreeViewFilterIndicatorManager::newIndicator( const QString &filter )
+{
+  QgsLayerTreeViewIndicator *indicator = new QgsLayerTreeViewIndicator( this );
+  indicator->setIcon( mIcon );
+  updateIndicator( indicator, filter );
+  connect( indicator, &QgsLayerTreeViewIndicator::clicked, this, &QgsLayerTreeViewFilterIndicatorManager::onIndicatorClicked );
+  mIndicators.insert( indicator );
+  return indicator;
+}
+
+void QgsLayerTreeViewFilterIndicatorManager::updateIndicator( QgsLayerTreeViewIndicator *indicator, const QString &filter )
+{
+  indicator->setToolTip( QString( "<b>%1:</b><br>%2" ).arg( tr( "Filter" ) ).arg( filter ) );
+}
+
 
 void QgsLayerTreeViewFilterIndicatorManager::addOrRemoveIndicator( QgsLayerTreeNode *node, QgsVectorDataProvider *provider )
 {
   QString filter = provider->subsetString();
   if ( !filter.isEmpty() )
-    mLayerTreeView->addIndicator( node, mIndicator );
+  {
+    const QList<QgsLayerTreeViewIndicator *> nodeIndicators = mLayerTreeView->indicators( node );
+
+    // maybe the indicator exists already
+    foreach ( QgsLayerTreeViewIndicator *indicator, nodeIndicators )
+    {
+      if ( mIndicators.contains( indicator ) )
+      {
+        updateIndicator( indicator, filter );
+        return;
+      }
+    }
+
+    // it does not exist: need to create a new one
+    mLayerTreeView->addIndicator( node, newIndicator( filter ) );
+  }
   else
-    mLayerTreeView->removeIndicator( node, mIndicator );
+  {
+    const QList<QgsLayerTreeViewIndicator *> nodeIndicators = mLayerTreeView->indicators( node );
+
+    // there may be existing indicator we need to get rid of
+    foreach ( QgsLayerTreeViewIndicator *indicator, nodeIndicators )
+    {
+      if ( mIndicators.contains( indicator ) )
+      {
+        mLayerTreeView->removeIndicator( node, indicator );
+        indicator->deleteLater();
+        return;
+      }
+    }
+
+    // no indicator was there before, nothing to do
+  }
 }
diff --git a/src/app/qgslayertreeviewfilterindicator.h b/src/app/qgslayertreeviewfilterindicator.h
index d7b93252185..e7e73948438 100644
--- a/src/app/qgslayertreeviewfilterindicator.h
+++ b/src/app/qgslayertreeviewfilterindicator.h
@@ -18,6 +18,8 @@
 
 #include "qgslayertreeviewindicator.h"
 
+#include <QSet>
+
 class QgsLayerTreeNode;
 class QgsLayerTreeView;
 class QgsVectorDataProvider;
@@ -43,11 +45,14 @@ class QgsLayerTreeViewFilterIndicatorManager : public QObject
     void onIndicatorClicked( const QModelIndex &index );
 
   private:
+    QgsLayerTreeViewIndicator *newIndicator( const QString &filter );
+    void updateIndicator( QgsLayerTreeViewIndicator *indicator, const QString &filter );
     void addOrRemoveIndicator( QgsLayerTreeNode *node, QgsVectorDataProvider *provider );
 
   private:
     QgsLayerTreeView *mLayerTreeView;
-    QgsLayerTreeViewIndicator *mIndicator = nullptr;
+    QIcon mIcon;
+    QSet<QgsLayerTreeViewIndicator *> mIndicators;
 };
 
 #endif // QGSLAYERTREEVIEWFILTERINDICATOR_H