Qt 5.13 | Qt WebEngine | WebEngine Quick Nano Browser

Qt 5.13.2 Reference Documentation

# WebEngine Quick Nano Browser

A web browser implemented using the WebEngineView QML type.

Quick Nano Browser demonstrates how to use the Qt WebEngine QML types to develop a small web browser application that consists of a browser window with a title bar, toolbar, tab view, and status bar. The web content is loaded in a web engine view within the tab view. If certificate errors occur, users are prompted for action in a message dialog. The status bar pops up to display the URL of a hovered link.

A web page can issue a request for being displayed in fullscreen mode. Users can allow full screen mode by using a toolbar button. They can leave fullscreen mode by using a keyboard shortcut. Additional toolbar buttons enable moving backwards and forwards in the browser history, reloading tab content, and opening a settings menu for enabling the following features: JavaScript, plugins, fullscreen mode, off the record, HTTP disk cache, autoloading images, and ignoring certificate errors.

#### Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

#### Creating the Main Browser Window

When the browser main window is loaded, it creates an empty tab using the default profile. Each tab is a web engine view that fills the main window.

We create the main window in the BrowserWindow.qml file using the ApplicationWindow type:

      ApplicationWindow {
          id: browserWindow
          property QtObject applicationRoot
          property Item currentWebView: tabs.currentIndex < tabs.count ? tabs.getTab(tabs.currentIndex).item : null
          ...
          width: 1300
          height: 900
          visible: true
          title: currentWebView && currentWebView.title

We use the TabView Qt Quick control to create an empty tab view that fills the main window. We set the tab active first, to make sure that the tab item is immediately instantiated:

          TabView {
              id: tabs
              function createEmptyTab(profile) {
                  var tab = addTab("", tabComponent);
                  // We must do this first to make sure that tab.active gets set so that tab.item gets instantiated immediately.
                  tab.active = true;
                  tab.title = Qt.binding(function() { return tab.item.title });
                  tab.item.profile = profile;
                  return tab;
              }

              anchors.top: parent.top
              anchors.bottom: devToolsView.top
              anchors.left: parent.left
              anchors.right: parent.right
              Component.onCompleted: createEmptyTab(defaultProfile)

The tab contains a web engine view that loads web content:

              // Add custom tab view style so we can customize the tabs to include a close button
              style: TabViewStyle {
                  property color frameColor: "#999"
                  property color fillColor: "#eee"
                  property color nonSelectedColor: "#ddd"
                  frameOverlap: 1
                  frame: Rectangle {
                      color: "#eee"
                      border.color: frameColor
                  }
                  tab: Rectangle {
                      id: tabRectangle
                      color: styleData.selected ? fillColor : nonSelectedColor
                      border.width: 1
                      border.color: frameColor
                      implicitWidth: Math.max(text.width + 30, 80)
                      implicitHeight: Math.max(text.height + 10, 20)
                      Rectangle { height: 1 ; width: parent.width ; color: frameColor}
                      Rectangle { height: parent.height ; width: 1; color: frameColor}
                      Rectangle { x: parent.width - 2; height: parent.height ; width: 1; color: frameColor}
                      Text {
                          id: text
                          anchors.left: parent.left
                          anchors.verticalCenter: parent.verticalCenter
                          anchors.leftMargin: 6
                          text: styleData.title
                          elide: Text.ElideRight
                          color: styleData.selected ? "black" : frameColor
                      }
                      Button {
                          anchors.right: parent.right
                          anchors.verticalCenter: parent.verticalCenter
                          anchors.rightMargin: 4
                          height: 12
                          style: ButtonStyle {
                              background: Rectangle {
                                  implicitWidth: 12
                                  implicitHeight: 12
                                  color: control.hovered ? "#ccc" : tabRectangle.color
                                  Text {text: "x" ; anchors.centerIn: parent ; color: "gray"}
                              }}
                          onClicked: tabs.removeTab(styleData.index);
                      }
                  }
              }

              Component {
                  id: tabComponent
                  WebEngineView {
                      id: webEngineView
                      focus: true

We use the Action type to create new tabs:

          Action {
              shortcut: StandardKey.AddTab
              onTriggered: {
                  tabs.createEmptyTab(tabs.count != 0 ? currentWebView.profile : defaultProfile);
                  tabs.currentIndex = tabs.count - 1;
                  addressBar.forceActiveFocus();
                  addressBar.selectAll();
              }

We use the TextField Qt Quick Control within a ToolBar to create an address bar that shows the current URL and where users can enter another URL:

          toolBar: ToolBar {
              id: navigationBar
                  RowLayout {
                      anchors.fill: parent
          ...
                      TextField {
                          id: addressBar
          ...
                          focus: true
                          Layout.fillWidth: true
                          text: currentWebView && currentWebView.url
                          onAccepted: currentWebView.url = utils.fromUserInput(text)
                      }

#### Handling Certificate Errors

If the certificate of the site being loaded triggers a certificate error, we call the defer() QML method to pause the URL request and wait for user input:

                      onCertificateError: function(error) {
                          error.defer();
                          sslDialog.enqueue(error);
                      }

We use the MessageDialog type to prompt users to continue or cancel the loading of the web page. If users select Yes, we call the ignoreCertificateError() method to ignore the error and continue loading content from the URL. If users select No, we call the rejectCertificate() method to reject the request and stop loading content from the URL:

          MessageDialog {
              id: sslDialog

              property var certErrors: []
              icon: StandardIcon.Warning
              standardButtons: StandardButton.No | StandardButton.Yes
              title: "Server's certificate not trusted"
              text: "Do you wish to continue?"
              detailedText: "If you wish so, you may continue with an unverified certificate. " +
                            "Accepting an unverified certificate means " +
                            "you may not be connected with the host you tried to connect to.\n" +
                            "Do you wish to override the security check and continue?"
              onYes: {
                  certErrors.shift().ignoreCertificateError();
                  presentError();
              }
              onNo: reject()
              onRejected: reject()

              function reject(){
                  certErrors.shift().rejectCertificate();
                  presentError();
              }
              function enqueue(error){
                  certErrors.push(error);
                  presentError();
              }
              function presentError(){
                  visible = certErrors.length > 0
              }
          }

#### Entering and Leaving Fullscreen Mode

We create a menu item for allowing fullscreen mode in a settings menu that we place on the tool bar. Also, we create an action for leaving fullscreen mode by using a keyboard shortcut. We call the accept() method to accept the fullscreen request. The methdod sets the isFullScreen property to be equal to the toggleOn property.

                      onFullScreenRequested: function(request) {
                          if (request.toggleOn) {
                              webEngineView.state = "FullScreen";
                              browserWindow.previousVisibility = browserWindow.visibility;
                              browserWindow.showFullScreen();
                              fullScreenNotification.show();
                          } else {
                              webEngineView.state = "";
                              browserWindow.visibility = browserWindow.previousVisibility;
                              fullScreenNotification.hide();
                          }
                          request.accept();
                      }

When entering fullscreen mode, we display a notification using the FullScreenNotification custom type that we create in FullScreenNotification.qml.

We use the Action type in the settings menu to create a shortcut for leaving fullscreen mode by pressing the escape key:

          Settings {
              id : appSettings
              property alias fullScreenSupportEnabled: fullScreenSupportEnabled.checked
              property alias autoLoadIconsForPage: autoLoadIconsForPage.checked
              property alias touchIconsEnabled: touchIconsEnabled.checked
              property alias webRTCPublicInterfacesOnly : webRTCPublicInterfacesOnly.checked
              property alias devToolsEnabled: devToolsEnabled.checked
              property alias pdfViewerEnabled: pdfViewerEnabled.checked
          }

          Action {
              shortcut: "Escape"
              onTriggered: {
                  if (currentWebView.state == "FullScreen") {
                      browserWindow.visibility = browserWindow.previousVisibility;
                      fullScreenNotification.hide();
                      currentWebView.triggerWebAction(WebEngineView.ExitFullScreen);
                  }
              }
          }

#### Files and Attributions

The example uses icons from the Tango Icon Library:

Tango Icon Library | Public Domain

Example project @ code.qt.io