WebEngine Widgets 拼写检查器范例

拼写检查器 演示如何将拼写检查支持集成到 HTML 表单中，使用户能够提交拼写检查消息。

运行范例

要运行范例从 Qt Creator ，打开欢迎模式，然后选择范例从范例。更多信息，拜访构建和运行范例 .

字典

To be able to check the spelling, we need to provide the spellchecker with dictionaries. The Qt WebEngine spellchecker supports dictionaries provided by the Hunspell project on all platforms and native dictionaries provided by macOS . In this example, we want to support the English and German languages.

For Hunspell dictionaries to be supported they have to be compiled into a special binary format. A Hunspell dictionary consists of two files:

A .dic file that is a dictionary containing words for the language
An .aff file that defines the meaning of special flags in the dictionary

These two files can be converted into the bdic format by using the qwebengine_convert_dict tool that is shipped together with Qt.

In this example, we are going to compile en_US and de_DE dictionaries. However, the real full dictionaries would take too much space for the purposes of this example. Therefore, we have created two dummy dictionaries that contain the following words and can be used to demonstrate the conversion process:

English dictionary: I, you, he, she, it, we, they, love, loves, qt
German dictionary: ich, du, er, sie, es, wir, ihr, sie, Sie, liebe, liebst, liebt, lieben, liebt, qt

Each word in a dictionary can be prefixed with q . For more information about how to create dic and aff files, see the Hunspell dictionary file format specification in the Hunspell Project .

When a specific spellchecking language is requested, Qt WebEngine will try to load the already compiled matching .bdic file first from qtwebengine_dictionaries directories relative to the executable, then it will look in QT_INSTALL_PREFIX/qtwebengine_dictionaries .

On macOS , because this example was configured to use Hunspell dictionaries, Qt WebEngine will look in the qtwebengine_dictionaries directory located inside the application bundle 资源 directory, and also in the 资源 directory located inside the Qt framework bundle.

We specify the QMAKE_EXTRA_COMPILERS parameter in the project file to add a conversion step to the build process:

qtPrepareTool(CONVERT_TOOL, qwebengine_convert_dict)
debug_and_release {
    CONFIG(debug, debug|release): DICTIONARIES_DIR = debug/qtwebengine_dictionaries
    else: DICTIONARIES_DIR = release/qtwebengine_dictionaries
} else {
    DICTIONARIES_DIR = qtwebengine_dictionaries
}
dict_base_paths = en/en-US de/de-DE
for (base_path, dict_base_paths) {
    dict.files += $$PWD/dict/$${base_path}.dic
}
dictoolbuild.input = dict.files
dictoolbuild.output = $${DICTIONARIES_DIR}/${QMAKE_FILE_BASE}.bdic
dictoolbuild.depends = ${QMAKE_FILE_PATH}/${QMAKE_FILE_BASE}.aff
dictoolbuild.commands = $${CONVERT_TOOL} ${QMAKE_FILE_IN} ${QMAKE_FILE_OUT}
dictoolbuild.name = Build ${QMAKE_FILE_IN_BASE}
dictoolbuild.CONFIG = no_link target_predeps
QMAKE_EXTRA_COMPILERS += dictoolbuild

To set up a dictionary, we run qwebengine_convert_dict passing the file path of the dictionary dic and bdic files. The aff file and optional delta file are also picked up by the convert process. The output bdic file is placed into the qtwebengine_dictionaries local directory (or Resources directory), which the application binary will run from.

设置拼写检查器

The constructor of our class is trivial.

WebView::WebView(QWidget *parent)
    : QWebEngineView(parent)
{
    m_spellCheckLanguages["English"] = "en-US";
    m_spellCheckLanguages["German"] = "de-DE";
    QWebEngineProfile *profile = page()->profile();
    profile->setSpellCheckEnabled(true);
    profile->setSpellCheckLanguages({"en-US"});

We define simple mapping between our dictionary filenames and the actual language display name. We will use that mapping to display names of dictionaries in the context menu. Spellchecking is disabled by default. Therefore we also enable spellchecker and set the English dictionary. When Qt WebEngine's spellcheck service initializes, it will try to load the bdict dictionaries and to check them for consistency. Any errors are logged by using the qWarning () 函数。

切换拼写检查语言

The current language used for spellchecking is defined per profile, and can get set using the QWebEngineProfile::setSpellCheckLanguage method. When the user clicks on an underlined misspelled word, the default context menu displays up to four suggestions. Selecting one will replace the misspelled word. We could reimplement a number of suggestions, by overriding QWebEngineView::contextMenuEvent and using QWebEngineContextMenuData::spellCheckerSuggestions , but we will demonstrate how to add langague options in the context menu instead:

void WebView::contextMenuEvent(QContextMenuEvent *event)
{
    const QWebEngineContextMenuData &data = page()->contextMenuData();
    Q_ASSERT(data.isValid());
    if (!data.isContentEditable()) {
        QWebEngineView::contextMenuEvent(event);
        return;
    }
    QWebEngineProfile *profile = page()->profile();
    const QStringList &languages = profile->spellCheckLanguages();
    QMenu *menu = page()->createStandardContextMenu();
    menu->addSeparator();
    QAction *spellcheckAction = new QAction(tr("Check Spelling"), nullptr);
    spellcheckAction->setCheckable(true);
    spellcheckAction->setChecked(profile->isSpellCheckEnabled());
    connect(spellcheckAction, &QAction::toggled, this, [profile](bool toogled) {
        profile->setSpellCheckEnabled(toogled);
    });
    menu->addAction(spellcheckAction);
    if (profile->isSpellCheckEnabled()) {
        QMenu *subMenu = menu->addMenu(tr("Select Language"));
        foreach (const QString &str, m_spellCheckLanguages.keys()) {
            QAction *action = subMenu->addAction(str);
            action->setCheckable(true);
            QString lang = m_spellCheckLanguages[str];
            action->setChecked(languages.contains(lang));
            connect(action, &QAction::triggered, this, [profile, lang](){
               profile->setSpellCheckLanguages(QStringList()<<lang);
            });
        }
    }
    connect(menu, &QMenu::aboutToHide, menu, &QObject::deleteLater);
    menu->popup(event->globalPos());
}

Above, we get the QWebEngineContextMenuData instance using the QWebEnginePage::contextMenuData method. We use it to be notified when the user clicks on an editable field and show the Check Spelling item in the context menu. Moreover, if spellchecking is enabled, we also add the 选择语言 submenu with the supported languages. When an action is triggered, we set the language with the QWebEngineProfile::setSpellCheckLanguage call.

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