[feature] Expose option to load vector tile sources from files

in Data Source Manager

The Vector Tile tab now includes choices for selecting from a
"Service" (the existing, connection based approach for adding
vector tiles from online sources) or "File" (the new option
which allows directly adding VTPK or MBTiles vector tile files)

src/gui/vectortile/qgsvectortilesourceselect.cpp

@@ -22,6 +22,8 @@
 #include "qgsvectortileconnection.h"
 #include "qgsvectortileconnectiondialog.h"
 #include "qgsarcgisvectortileconnectiondialog.h"
+#include "qgsprovidermetadata.h"
+#include "qgsproviderutils.h"
 
 #include <QFileDialog>
 #include <QMessageBox>
@@ -36,10 +38,25 @@ QgsVectorTileSourceSelect::QgsVectorTileSourceSelect( QWidget *parent, Qt::Windo
 {
   setupUi( this );
 
+  QgsGui::enableAutoGeometryRestore( this );
+
   setWindowTitle( tr( "Add Vector Tile Layer" ) );
-  mConnectionsGroupBox->setTitle( tr( "Vector Tile Connections" ) );
 
-  QgsGui::enableAutoGeometryRestore( this );
+  mRadioSourceService->setChecked( true );
+  mStackedWidget->setCurrentIndex( 1 );
+
+  connect( mRadioSourceFile, &QRadioButton::toggled, this, [this]
+  {
+    mStackedWidget->setCurrentIndex( 0 );
+
+    emit enableButtons( !mFileWidget->filePath().isEmpty() );
+  } );
+  connect( mRadioSourceService, &QRadioButton::toggled, this, [this]
+  {
+    mStackedWidget->setCurrentIndex( 1 );
+
+    emit enableButtons( !cmbConnections->currentText().isEmpty() );
+  } );
 
   btnNew->setPopupMode( QToolButton::InstantPopup );
   QMenu *newMenu = new QMenu( btnNew );
@@ -63,6 +80,15 @@ QgsVectorTileSourceSelect::QgsVectorTileSourceSelect( QWidget *parent, Qt::Windo
   setupButtons( buttonBox );
 
   populateConnectionList();
+
+  mFileWidget->setDialogTitle( tr( "Open Vector Tile Dataset" ) );
+  mFileWidget->setFilter( QgsProviderRegistry::instance()->fileVectorTileFilters() );
+  mFileWidget->setStorageMode( QgsFileWidget::GetFile );
+  mFileWidget->setOptions( QFileDialog::HideNameFilterDetails );
+  connect( mFileWidget, &QgsFileWidget::fileChanged, this, [ = ]( const QString & path )
+  {
+    emit enableButtons( ! path.isEmpty() );
+  } );
 }
 
 void QgsVectorTileSourceSelect::btnNew_clicked()
@@ -158,8 +184,31 @@ void QgsVectorTileSourceSelect::btnLoad_clicked()
 
 void QgsVectorTileSourceSelect::addButtonClicked()
 {
-  const QString uri = QgsVectorTileProviderConnection::encodedUri( QgsVectorTileProviderConnection::connection( cmbConnections->currentText() ) );
-  emit addVectorTileLayer( uri, cmbConnections->currentText() );
+  if ( mRadioSourceService->isChecked() )
+  {
+
+    const QString uri = QgsVectorTileProviderConnection::encodedUri( QgsVectorTileProviderConnection::connection( cmbConnections->currentText() ) );
+    emit addVectorTileLayer( uri, cmbConnections->currentText() );
+  }
+  else if ( mRadioSourceFile->isChecked() )
+  {
+    const QString filePath = mFileWidget->filePath();
+    const QList< QgsProviderRegistry::ProviderCandidateDetails > providers = QgsProviderRegistry::instance()->preferredProvidersForUri( filePath );
+    QString providerKey;
+    for ( const QgsProviderRegistry::ProviderCandidateDetails &details : providers )
+    {
+      if ( details.layerTypes().contains( Qgis::LayerType::VectorTile ) )
+      {
+        providerKey = details.metadata()->key();
+      }
+    }
+
+    QVariantMap parts;
+    parts.insert( QStringLiteral( "path" ), filePath );
+    const QString uri = QgsProviderRegistry::instance()->encodeUri( providerKey, parts );
+
+    emit addVectorTileLayer( uri, QgsProviderUtils::suggestLayerNameFromFilePath( filePath ) );
+  }
 }
 
 void QgsVectorTileSourceSelect::populateConnectionList()