MATLAB: Drop down, App Designer

Question

Hy everyboby, I would like that in the second tab "evaporazione_mensile" changes the graph with pop-up menù. I wrote the function called "Lista_anniValueChanged", and I would like it changes the graph, but I can't do it and the graph is always the same.

Best regard Dario

    % code
      classdef app1_1 < matlab.apps.AppBase
          % Properties that correspond to app components
          properties (Access = public)
              UIFigure              matlab.ui.Figure
              TabGroup              matlab.ui.container.TabGroup
              Evporazione_annuale   matlab.ui.container.Tab
              UIAxes                matlab.ui.control.UIAxes
              Evaporazione_mensile  matlab.ui.container.Tab
              UIAxes2               matlab.ui.control.UIAxes
              ANNILabel             matlab.ui.control.Label
              Lista_anni            matlab.ui.control.DropDown
          end
          methods (Access = private)
              % Code that executes after component creation
              function startupFcn(app)
               load('C:\Users\cecch\Documents\UNIVERSITA\Impianti Speciali Idraulici\Dati Portata\workspace_evaporazione.mat')
                  selectedTab = app.TabGroup.SelectedTab;
                  bar(app.UIAxes,1:12,E_pennman.Annuale,0.7,'r')
                  hold(app.UIAxes)
                  bar(app.UIAxes,1:12,E_Linacre.Annuale,0.5,'g')
                  bar(app.UIAxes,1:12,E_Visentini.Annuale,0.4,'b')
                  legend(app.UIAxes,'Penman','Linacre','Visentini','Location','southeast')
              end
              % Value changed function: Lista_anni
              function Lista_anniValueChanged(app, event)
                  value = app.Lista_anni.Value
                  if ( value==1 )
                      plot(app.UIAxes2,1:3,5:7,'r')
                  else ( value==2 )
                     plot(app.UIAxes2,1:3,5:7,'b')
                  end
              end
          end
          % App initialization and construction
          methods (Access = private)
              % Create UIFigure and components
              function createComponents(app)
                  % Create UIFigure
                  app.UIFigure = uifigure;
                  app.UIFigure.Position = [100 100 740 535];
                  app.UIFigure.Name = 'UI Figure';
                  % Create TabGroup
                  app.TabGroup = uitabgroup(app.UIFigure);
                  app.TabGroup.Position = [41 17 657 499];
                  % Create Evporazione_annuale
                  app.Evporazione_annuale = uitab(app.TabGroup);
                  app.Evporazione_annuale.Title = 'Evaporazione_annuale';
                  app.Evporazione_annuale.BackgroundColor = [0.8 0.8 0.8];
                  % Create UIAxes
                  app.UIAxes = uiaxes(app.Evporazione_annuale);
                  title(app.UIAxes, 'Evaporazione')
                  xlabel(app.UIAxes, 'ANNI')
                  ylabel(app.UIAxes, 'mm ')
                  app.UIAxes.FontSize = 16;
                  app.UIAxes.Position = [33 -125 460 571];
                  % Create Evaporazione_mensile
                  app.Evaporazione_mensile = uitab(app.TabGroup);
                  app.Evaporazione_mensile.Title = 'Evaporazione_mensile';
                  % Create UIAxes2
                  app.UIAxes2 = uiaxes(app.Evaporazione_mensile);
                  title(app.UIAxes2, 'Evaporazione Mensile')
                  xlabel(app.UIAxes2, 'MESI')
                  ylabel(app.UIAxes2, 'mm')
                  app.UIAxes2.FontSize = 16;
                  app.UIAxes2.Position = [25 26 469 428];
                  % Create ANNILabel
                  app.ANNILabel = uilabel(app.Evaporazione_mensile);
                  app.ANNILabel.HorizontalAlignment = 'right';
                  app.ANNILabel.Position = [493 392 34 15];
                  app.ANNILabel.Text = 'ANNI';
                  % Create Lista_anni
                  app.Lista_anni = uidropdown(app.Evaporazione_mensile);
                  app.Lista_anni.Items = {'1', '2'};
                  app.Lista_anni.Editable = 'on';
                  app.Lista_anni.ValueChangedFcn = createCallbackFcn(app, @Lista_anniValueChanged, true);
                  app.Lista_anni.BackgroundColor = [1 1 1];
                  app.Lista_anni.Position = [542 388 100 22];
                  app.Lista_anni.Value = '1';
              end
          end
          methods (Access = public)
              % Construct app
              function app = app1_1
                  % Create and configure components
                  createComponents(app)
                  % Register the app with App Designer
                  registerApp(app, app.UIFigure)
                  % Execute the startup function
                  runStartupFcn(app, @startupFcn)
                  if nargout == 0
                      clear app
                  end
              end
              % Code that executes before app deletion
              function delete(app)
                  % Delete UIFigure when app is deleted
                  delete(app.UIFigure)
              end
          end
      end

Answer 1

app.Lista_anni.Value return a char, you need to modify the comparison like this

if ( value=='1' )
plot(app.UIAxes2,1:3,5:7,'r')
else ( value=='2' )
plot(app.UIAxes2,1:3,5:7,'b')
end