mainwindow.cpp Example File

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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();
  }