remove bug when using history and bands are added twice + no error when using...

remove bug when using history and bands are added twice + no error when using history and previous input layer is not loaded

BandTableWidget.py

@@ -54,6 +54,9 @@ class BandTableWidget(BASE, WIDGET):
         self.btnUp.setIcon(QgsApplication.getThemeIcon('/mActionArrowUp.svg'))
         self.btnDown.setIcon(QgsApplication.getThemeIcon('/mActionArrowDown.svg'))
         self.layer = None
+        
+        # when alg is launched by user, display bands in table of 1st raster layer
+        self.layerChanged()
       
     # when user changes selected layer in combobox
     def layerChanged(self):
@@ -61,17 +64,19 @@ class BandTableWidget(BASE, WIDGET):
         self._removeBandData()
         # get raster layer
         layer = self.cmbLayers.currentLayer()
-        #QMessageBox.information(None, self.tr('tralala'), self.tr(str(layer.name())))
-        input_raster = gdal.Open(layer.source())
-        # get number of bands in raster
-        nbands = input_raster.RasterCount
-        # for each band
-        for band_number in range(nbands):
-            band = input_raster.GetRasterBand(band_number + 1)
-            # add band number to table
-            bandnumber = str(band_number+1)
-            bandname = band.GetDescription()
-            self._addBandData(bandnumber, bandname)
+        # if there is one 
+        if layer != None:
+            #QMessageBox.information(None, self.tr('tralala'), self.tr(str(layer.name())))
+            input_raster = gdal.Open(layer.source())
+            # get number of bands in raster
+            nbands = input_raster.RasterCount
+            # for each band
+            for band_number in range(nbands):
+                band = input_raster.GetRasterBand(band_number + 1)
+                # add band number to table
+                bandnumber = str(band_number+1)
+                bandname = band.GetDescription()
+                self._addBandData(bandnumber, bandname)
     
     # add selected raster band number and names to table
     def _addBandData(self, bandnumber, bandname):
@@ -138,7 +143,7 @@ class BandTableWidget(BASE, WIDGET):
             if item:
                 row = [item.text(0), item.text(1), item.text(2)]
                 band_names.append(row)
-        QMessageBox.information(None, self.tr('tralala'), self.tr(str(band_names)))
+        #QMessageBox.information(None, self.tr('tralala'), self.tr(str(band_names)))
         return band_names
 
     def setLayer(self, layer):
@@ -156,17 +161,20 @@ class BandTableWidget(BASE, WIDGET):
         param = value.split(';')
         # setting input layer
         layer_name = param[0]
-        layer = QgsProject.instance().mapLayersByName(layer_name)[0]
-        self.cmbLayers.setLayer(layer)
-        # setting table values
-        rows = param[2:]
-        for r in rows:
-            v = r.split(',')
-            item = QTreeWidgetItem()
-            item.setText(0, v[0])
-            item.setText(1, v[1])
-            item.setText(2, v[2])
-            self.bandClassTree.addTopLevelItem(item)
+        # if layer is loaded in project
+        if QgsProject.instance().mapLayersByName(layer_name):
+            layer = QgsProject.instance().mapLayersByName(layer_name)[0]
+            self.cmbLayers.setLayer(layer)
+            # setting table values
+            self.bandClassTree.clear()
+            rows = param[2:]
+            for r in rows:
+                v = r.split(',')
+                item = QTreeWidgetItem()
+                item.setText(0, v[0])
+                item.setText(1, v[1])
+                item.setText(2, v[2])
+                self.bandClassTree.addTopLevelItem(item)
 
     # return a list where 1st element is input raster path
     # and then each element for a table row