Qt 5.11 | Qt WebEngine | WebEngine StyleSheet Browser Example | mainwindow.cpp Example File

Qt 5.11.3 Reference Documentation

# mainwindow.cpp Example File

webenginewidgets/stylesheetbrowser/mainwindow.cpp

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      #include "mainwindow.h"
      #include "stylesheetdialog.h"
      #include "ui_mainwindow.h"

      static QMap<QString, QString> defaultStyleSheets = {
          {"Upside down", "body { -webkit-transform: rotate(180deg); }"}
      };

      MainWindow::MainWindow(const QUrl &url) :
          QMainWindow(),
          ui(new Ui::MainWindow)
      {
          ui->setupUi(this);

          connect(ui->urlBar, &QLineEdit::returnPressed, this, &MainWindow::urlEntered);
          connect(ui->webEngineView, &QWebEngineView::urlChanged, this, &MainWindow::urlChanged);
          connect(ui->settingsButton, &QPushButton::clicked, this, &MainWindow::showStyleSheetsDialog);
          connect(ui->reloadButton, &QPushButton::clicked, this, &MainWindow::reloadRequested);

          QSettings settings;
          settings.beginGroup("styleSheets");
          QStringList styleSheets = settings.allKeys();
          if (styleSheets.empty()) {
              // Add back default style sheets if the user cleared them out
              loadDefaultStyleSheets();
          } else {
              for (auto name : qAsConst(styleSheets)) {
                  StyleSheet styleSheet = settings.value(name).value<StyleSheet>();
                  if (styleSheet.second)
                      insertStyleSheet(name, styleSheet.first, false);
              }
          }
          settings.endGroup();

          ui->webEngineView->setUrl(url);
      }

      MainWindow::~MainWindow()
      {
          delete ui;
      }

      void MainWindow::insertStyleSheet(const QString &name, const QString &source, bool immediately)
      {
          QWebEngineScript script;
          QString s = QString::fromLatin1("(function() {"\
                                          "    css = document.createElement('style');"\
                                          "    css.type = 'text/css';"\
                                          "    css.id = '%1';"\
                                          "    document.head.appendChild(css);"\
                                          "    css.innerText = '%2';"\
                                          "})()").arg(name).arg(source.simplified());
          if (immediately)
              ui->webEngineView->page()->runJavaScript(s, QWebEngineScript::ApplicationWorld);

          script.setName(name);
          script.setSourceCode(s);
          script.setInjectionPoint(QWebEngineScript::DocumentReady);
          script.setRunsOnSubFrames(true);
          script.setWorldId(QWebEngineScript::ApplicationWorld);
          ui->webEngineView->page()->scripts().insert(script);
      }

      void MainWindow::removeStyleSheet(const QString &name, bool immediately)
      {
          QString s = QString::fromLatin1("(function() {"\
                                          "    var element = document.getElementById('%1');"\
                                          "    element.outerHTML = '';"\
                                          "    delete element;"\
                                          "})()").arg(name);
          if (immediately)
              ui->webEngineView->page()->runJavaScript(s, QWebEngineScript::ApplicationWorld);

          QWebEngineScript script = ui->webEngineView->page()->scripts().findScript(name);
          ui->webEngineView->page()->scripts().remove(script);
      }

      bool MainWindow::hasStyleSheet(const QString &name)
      {
          QWebEngineScript script = ui->webEngineView->page()->scripts().findScript(name);
          return !script.isNull();
      }

      void MainWindow::loadDefaultStyleSheets()
      {
          QSettings settings;
          settings.beginGroup("styleSheets");

          auto it = defaultStyleSheets.constBegin();
          while (it != defaultStyleSheets.constEnd()) {
              settings.setValue(it.key(), QVariant::fromValue(qMakePair(it.value(), true)));
              insertStyleSheet(it.key(), it.value(), false);
              ++it;
          }

          settings.endGroup();
      }

      void MainWindow::urlEntered()
      {
          ui->webEngineView->setUrl(QUrl::fromUserInput(ui->urlBar->text()));
      }

      void MainWindow::urlChanged(const QUrl &url)
      {
          ui->urlBar->setText(url.toString());
      }

      void MainWindow::showStyleSheetsDialog()
      {
          StylesheetDialog *dialog = new StylesheetDialog(this);
          dialog->show();
      }

      void MainWindow::reloadRequested()
      {
          ui->webEngineView->reload();
      }