Add Cancel button to webrequest sample

samples/webrequest/webrequest.cpp

@@ -144,9 +144,17 @@ public:
 
         mainSizer->Add(m_notebook, wxSizerFlags(1).Expand().Border());
 
-        m_startButton = new wxButton(this, wxID_ANY, "&Start Request");
+        wxStdDialogButtonSizer* btnSizer = new wxStdDialogButtonSizer();
+        m_cancelButton = new wxButton(this, wxID_CANCEL, "Cancel");
+        m_cancelButton->Bind(wxEVT_BUTTON, &WebRequestFrame::OnCancelButton, this);
+        m_cancelButton->Disable();
+        btnSizer->AddButton(m_cancelButton);
+
+        m_startButton = new wxButton(this, wxID_OK, "&Start Request");
         m_startButton->Bind(wxEVT_BUTTON, &WebRequestFrame::OnStartButton, this);
-        mainSizer->Add(m_startButton, wxSizerFlags().Border());
+        btnSizer->AddButton(m_startButton);
+        btnSizer->Realize();
+        mainSizer->Add(btnSizer, wxSizerFlags().Border());
 
         wxCommandEvent evt;
         OnPostCheckBox(evt);
@@ -161,7 +169,7 @@ public:
         m_downloadProgressTimer.Bind(wxEVT_TIMER,
             &WebRequestFrame::OnProgressTimer, this);
 
-        m_downloadRequest = NULL;
+        m_currentRequest = NULL;
     }
 
     void OnStartButton(wxCommandEvent& WXUNUSED(evt))
@@ -171,6 +179,7 @@ public:
         // Create request for the specified URL from the default session
         wxObjectDataPtr<wxWebRequest> request(wxWebSession::GetDefault().CreateRequest(
             m_urlTextCtrl->GetValue()));
+        m_currentRequest = request.get();
 
         // Bind event for state change
         request->Bind(wxEVT_WEBREQUEST_STATE, &WebRequestFrame::OnWebRequestState, this);
@@ -194,7 +203,6 @@ public:
                 }
                 break;
             case Page_Download:
-            m_downloadRequest = request.get();
                 request->SetStorage(wxWebRequest::Storage_File);
                 m_downloadGauge->SetValue(0);
                 m_downloadGauge->Pulse();
@@ -218,9 +226,22 @@ public:
         request->Start();
     }
 
+    void OnCancelButton(wxCommandEvent& WXUNUSED(evt))
+    {
+        if ( m_currentRequest )
+            m_currentRequest->Cancel();
+    }
+
     void OnWebRequestState(wxWebRequestEvent& evt)
     {
         m_startButton->Enable(evt.GetState() != wxWebRequest::State_Active);
+        m_cancelButton->Enable(evt.GetState() == wxWebRequest::State_Active);
+
+        if ( evt.GetState() != wxWebRequest::State_Active )
+        {
+            m_currentRequest = NULL;
+            m_downloadProgressTimer.Stop();
+        }
 
         switch (evt.GetState())
         {
@@ -244,13 +265,8 @@ public:
                         break;
                     case Page_Download:
                     {
-                    // Force last progress update
+                        m_downloadGauge->SetValue(100);
-                    wxTimerEvent timerEvt;
+                        m_downloadStaticText->SetLabel("");
-                    OnProgressTimer(timerEvt);
-
-                    // Stop updating download progress
-                    m_downloadRequest = NULL;
-                    m_downloadProgressTimer.Stop();
 
                         GetStatusBar()->SetStatusText("Download completed");
 
@@ -274,12 +290,15 @@ public:
                 break;
 
             case wxWebRequest::State_Failed:
-                // Stop updating download progress
-                m_downloadRequest = NULL;
-                m_downloadProgressTimer.Stop();
                 wxLogError("Web Request failed: %s", evt.GetErrorDescription());
                 GetStatusBar()->SetStatusText("");
                 break;
+
+            case wxWebRequest::State_Cancelled:
+                m_downloadGauge->SetValue(0);
+                m_downloadStaticText->SetLabel("");
+                GetStatusBar()->SetStatusText("Cancelled");
+                break;
         }
     }
 
@@ -311,15 +330,15 @@ public:
 
     void OnProgressTimer(wxTimerEvent& WXUNUSED(evt))
     {
-        if (!m_downloadRequest || m_downloadRequest->GetBytesExpectedToReceive() <= 0)
+        if ( !m_currentRequest || m_currentRequest->GetBytesExpectedToReceive() <= 0 )
             return;
 
         
-        m_downloadGauge->SetValue((m_downloadRequest->GetBytesReceived() * 100) /
+        m_downloadGauge->SetValue((m_currentRequest->GetBytesReceived() * 100) /
-            m_downloadRequest->GetBytesExpectedToReceive());
+            m_currentRequest->GetBytesExpectedToReceive());
 
         m_downloadStaticText->SetLabelText(wxString::Format("%lld/%lld",
-            m_downloadRequest->GetBytesReceived(), m_downloadRequest->GetBytesExpectedToReceive()));
+            m_currentRequest->GetBytesReceived(), m_currentRequest->GetBytesExpectedToReceive()));
     }
 
     void OnPostCheckBox(wxCommandEvent& WXUNUSED(evt))
@@ -358,7 +377,9 @@ private:
     wxNotebook* m_notebook;
     wxTextCtrl* m_urlTextCtrl;
     wxButton* m_startButton;
+    wxButton* m_cancelButton;
     wxStaticBitmap* m_imageStaticBitmap;
+    wxWebRequest* m_currentRequest;
 
     wxCheckBox* m_postCheckBox;
     wxTextCtrl* m_postContentTypeTextCtrl;
@@ -368,7 +389,6 @@ private:
     wxGauge* m_downloadGauge;
     wxStaticText* m_downloadStaticText;
     wxTimer m_downloadProgressTimer;
-    wxWebRequest* m_downloadRequest;
 
     wxStaticText* m_advCountStaticText;
     long long m_advCount;