qt 6.5.1 original

examples/widgets/tools/customcompleter/CMakeLists.txt

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+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+project(customcompleter LANGUAGES CXX)
+
+if(NOT DEFINED INSTALL_EXAMPLESDIR)
+    set(INSTALL_EXAMPLESDIR "examples")
+endif()
+
+set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/widgets/tools/customcompleter")
+
+find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
+
+qt_standard_project_setup()
+
+qt_add_executable(customcompleter
+    main.cpp
+    mainwindow.cpp mainwindow.h
+    textedit.cpp textedit.h
+)
+
+set_target_properties(customcompleter PROPERTIES
+    WIN32_EXECUTABLE TRUE
+    MACOSX_BUNDLE TRUE
+)
+
+target_link_libraries(customcompleter PRIVATE
+    Qt6::Core
+    Qt6::Gui
+    Qt6::Widgets
+)
+
+# Resources:
+set(customcompleter_resource_files
+    "resources/wordlist.txt"
+)
+
+qt_add_resources(customcompleter "customcompleter"
+    PREFIX
+        "/"
+    FILES
+        ${customcompleter_resource_files}
+)
+
+install(TARGETS customcompleter
+    RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
+    BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
+    LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
+)

examples/widgets/tools/customcompleter/customcompleter.pro

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+QT += widgets
+requires(qtConfig(completer))
+
+HEADERS   = mainwindow.h \
+            textedit.h
+SOURCES   = main.cpp \
+            mainwindow.cpp \
+            textedit.cpp
+RESOURCES = customcompleter.qrc
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/widgets/tools/customcompleter
+INSTALLS += target

examples/widgets/tools/customcompleter/customcompleter.qrc

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+<!DOCTYPE RCC><RCC version="1.0">
+<qresource prefix="/">
+   <file>resources/wordlist.txt</file>
+</qresource>
+</RCC>

examples/widgets/tools/customcompleter/doc/src/customcompleter.qdoc

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
+
+/*!
+    \example tools/customcompleter
+    \title Custom Completer Example
+
+    \ingroup examples-widgets-tools
+
+    \brief The Custom Completer example shows how to provide string-completion
+    facilities for an input widget based on data provided by a model. The
+    completer pops up suggestions for possible words based on the first three
+    characters input by the user and the user's choice of word is inserted
+    into the \c TextEdit using QTextCursor.
+
+    \image customcompleter-example.png
+
+    \section1 Setting Up The Resource File
+
+    The Custom Completer example requires a resource file, \e wordlist.txt,
+    that has a list of words to help QCompleter complete words. This file
+    contains the following:
+
+    \quotefile tools/customcompleter/customcompleter.qrc
+
+    \section1 TextEdit Class Definition
+
+    The \c TextEdit class is a subclass of QTextEdit with a custom
+    \c insertCompletion() slot and it reimplements the
+    \l{QAbstractScrollArea::keyPressEvent()}{keyPressEvent()} and the
+    \l{QWidget::focusInEvent()}{focusInEvent()} functions. \c TextEdit also
+    contains a private function \c textUnderCursor() and a private instance
+    of QCompleter, \c c.
+
+    \snippet tools/customcompleter/textedit.h 0
+
+    \section1 TextEdit Class Implementation
+
+    The constructor for \c TextEdit constructs a \c TextEdit with a parent and
+    initializes \c c. The instructions to use the completer is displayed on
+    the \c TextEdit object, using the
+    \l{QTextEdit::setPlainText()}{setPlainText()} function.
+
+    \snippet tools/customcompleter/textedit.cpp 0
+
+    In addition, \c TextEdit also includes a default destructor:
+
+    \snippet tools/customcompleter/textedit.cpp 1
+
+    The \c setCompleter() function accepts a \a completer and sets it up.
+    We use \c{if (c)} to check if \c c has been initialized. If it has been
+    initialized, the QObject::disconnect() function is invoked to disconnect
+    the signal from the slot. This is to ensure that no previous completer
+    object is still connected to the slot.
+
+    \snippet tools/customcompleter/textedit.cpp 2
+
+    We then instantiate \c c with \a completer and set it as \c{TextEdit}'s
+    widget. The completion mode and case sensitivity are also set and then
+    we connect the \l{QCompleter::activated()}{activated()} signal to the
+    \c insertCompletion() slot.
+
+    The \c completer() function is a getter function that returns \c c.
+
+    \snippet tools/customcompleter/textedit.cpp 3
+
+    The completer pops up the options available, based on the contents of
+    \e wordlist.txt, but the text cursor is responsible for filling in the
+    missing characters, according to the user's choice of word.
+
+    Suppose the user inputs "ACT" and accepts the completer's suggestion of
+    "ACTUAL". The \c completion string is then sent to \c insertCompletion()
+    by the completer's \l{QCompleter::activated()}{activated()} signal.
+
+    The \c insertCompletion() function is responsible for completing the word
+    using a QTextCursor object, \c tc. It validates to ensure that the
+    completer's widget is \c TextEdit before using \c tc to insert the extra
+    characters to complete the word.
+
+    \snippet tools/customcompleter/textedit.cpp 4
+
+    The figure below illustrates this process:
+
+    \image customcompleter-insertcompletion.png
+
+    \c{completion.length()} = 6
+
+    \c{c->completionPrefix().length()}=3
+
+    The difference between these two values is \c extra, which is 3. This
+    means that the last three characters from the right, "U", "A", and "L",
+    will be inserted by \c tc.
+
+    The \c textUnderCursor() function uses a QTextCursor, \c tc, to select a
+    word under the cursor and return it.
+
+    \snippet tools/customcompleter/textedit.cpp 5
+
+    The \c TextEdit class reimplements \l{QWidget::focusInEvent()}
+    {focusInEvent()} function, which is an event handler used to receive
+    keyboard focus events for the widget.
+
+    \snippet tools/customcompleter/textedit.cpp 6
+
+    The \l{QAbstractScrollArea::keyPressEvent()}{keyPressEvent()} is
+    reimplemented to ignore key events like Qt::Key_Enter, Qt::Key_Return,
+    Qt::Key_Escape, Qt::Key_Tab, and Qt::Key_Backtab so the completer can
+    handle them.
+
+    If there is an active completer, we cannot process the shortcut, Ctrl+E.
+
+    \snippet tools/customcompleter/textedit.cpp 7
+
+    We also handle other modifiers and shortcuts for which we do not want the
+    completer to respond to.
+
+    \snippet tools/customcompleter/textedit.cpp 8
+
+    Finally, we pop up the completer.
+
+    \section1 MainWindow Class Definition
+
+    The \c MainWindow class is a subclass of QMainWindow and implements a
+    private slot, \c about(). This class also has two private functions,
+    \c createMenu() and \c modelFromFile() as well as private instances of
+    QCompleter and \c TextEdit.
+
+    \snippet tools/customcompleter/mainwindow.h 0
+
+    \section1 MainWindow Class Implementation
+
+    The constructor constructs a \c MainWindow with a parent and initializes
+    the \c completer. It also instantiates a \c TextEdit and sets its
+    completer. A QStringListModel, obtained from \c modelFromFile(), is used
+    to populate the \c completer. The \c{MainWindow}'s central widget is set
+    to \c TextEdit and its size is set to 500 x 300.
+
+    \snippet tools/customcompleter/mainwindow.cpp 0
+
+    The \c createMenu() function creates the necessary QAction objects needed
+    for the "File" and "Help" menu and their \l{QAction::triggered()}
+    {triggered()} signals are connected to the \c quit(), \c about(), and
+    \c aboutQt() slots respectively.
+
+    \snippet tools/customcompleter/mainwindow.cpp 1
+
+    The \c modelFromFile() function accepts a \a fileName and attempts to
+    extract the contents of this file into a QStringListModel. We display the
+    Qt::WaitCursor when we are populating the QStringList, \c words, and
+    restore the mouse cursor when we are done.
+
+    \snippet tools/customcompleter/mainwindow.cpp 2
+
+    The \c about() function provides a brief description about the Custom
+    Completer example.
+
+    \snippet tools/customcompleter/mainwindow.cpp 3
+
+    \section1 \c main() Function
+
+    The \c main() function instantiates \c MainWindow and invokes the
+    \l{QWidget::show()}{show()} function.
+
+    \snippet tools/customcompleter/main.cpp 0
+*/

examples/widgets/tools/customcompleter/main.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include <QApplication>
+#include "mainwindow.h"
+
+//! [0]
+int main(int argc, char *argv[])
+{
+    Q_INIT_RESOURCE(customcompleter);
+
+    QApplication app(argc, argv);
+    MainWindow window;
+    window.show();
+    return app.exec();
+}
+//! [0]

examples/widgets/tools/customcompleter/mainwindow.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "mainwindow.h"
+#include "textedit.h"
+
+#include <QAction>
+#include <QApplication>
+#include <QCompleter>
+#include <QFile>
+#include <QMenuBar>
+#include <QMessageBox>
+#include <QStringListModel>
+
+//! [0]
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+{
+    createMenu();
+
+    completingTextEdit = new TextEdit;
+    completer = new QCompleter(this);
+    completer->setModel(modelFromFile(":/resources/wordlist.txt"));
+    completer->setModelSorting(QCompleter::CaseInsensitivelySortedModel);
+    completer->setCaseSensitivity(Qt::CaseInsensitive);
+    completer->setWrapAround(false);
+    completingTextEdit->setCompleter(completer);
+
+    setCentralWidget(completingTextEdit);
+    resize(500, 300);
+    setWindowTitle(tr("Completer"));
+}
+//! [0]
+
+//! [1]
+void MainWindow::createMenu()
+{
+    QAction *exitAction = new QAction(tr("Exit"), this);
+    QAction *aboutAct = new QAction(tr("About"), this);
+    QAction *aboutQtAct = new QAction(tr("About Qt"), this);
+
+    connect(exitAction, &QAction::triggered, qApp, &QApplication::quit);
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
+
+    QMenu *fileMenu = menuBar()->addMenu(tr("File"));
+    fileMenu->addAction(exitAction);
+
+    QMenu *helpMenu = menuBar()->addMenu(tr("About"));
+    helpMenu->addAction(aboutAct);
+    helpMenu->addAction(aboutQtAct);
+}
+//! [1]
+
+//! [2]
+QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
+{
+    QFile file(fileName);
+    if (!file.open(QFile::ReadOnly))
+        return new QStringListModel(completer);
+
+#ifndef QT_NO_CURSOR
+    QGuiApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
+#endif
+    QStringList words;
+
+    while (!file.atEnd()) {
+        QByteArray line = file.readLine();
+        if (!line.isEmpty())
+            words << QString::fromUtf8(line.trimmed());
+    }
+
+#ifndef QT_NO_CURSOR
+    QGuiApplication::restoreOverrideCursor();
+#endif
+    return new QStringListModel(words, completer);
+}
+//! [2]
+
+//! [3]
+void MainWindow::about()
+{
+    QMessageBox::about(this, tr("About"), tr("This example demonstrates the "
+        "different features of the QCompleter class."));
+}
+//! [3]
+

examples/widgets/tools/customcompleter/mainwindow.h

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+
+QT_BEGIN_NAMESPACE
+class QAbstractItemModel;
+class QCompleter;
+QT_END_NAMESPACE
+class TextEdit;
+
+//! [0]
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    MainWindow(QWidget *parent = nullptr);
+
+private slots:
+    void about();
+
+private:
+    void createMenu();
+    QAbstractItemModel *modelFromFile(const QString& fileName);
+
+    QCompleter *completer = nullptr;
+    TextEdit *completingTextEdit;
+};
+//! [0]
+
+#endif // MAINWINDOW_H

examples/widgets/tools/customcompleter/textedit.cpp

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "textedit.h"
+#include <QCompleter>
+#include <QKeyEvent>
+#include <QAbstractItemView>
+#include <QtDebug>
+#include <QApplication>
+#include <QModelIndex>
+#include <QAbstractItemModel>
+#include <QScrollBar>
+
+//! [0]
+TextEdit::TextEdit(QWidget *parent)
+    : QTextEdit(parent)
+{
+    setPlainText(tr("This TextEdit provides autocompletions for words that have more than"
+                    " 3 characters. You can trigger autocompletion using ") +
+                    QKeySequence("Ctrl+E").toString(QKeySequence::NativeText));
+}
+//! [0]
+
+//! [1]
+TextEdit::~TextEdit()
+{
+}
+//! [1]
+
+//! [2]
+void TextEdit::setCompleter(QCompleter *completer)
+{
+    if (c)
+        c->disconnect(this);
+
+    c = completer;
+
+    if (!c)
+        return;
+
+    c->setWidget(this);
+    c->setCompletionMode(QCompleter::PopupCompletion);
+    c->setCaseSensitivity(Qt::CaseInsensitive);
+    QObject::connect(c, QOverload<const QString &>::of(&QCompleter::activated),
+                     this, &TextEdit::insertCompletion);
+}
+//! [2]
+
+//! [3]
+QCompleter *TextEdit::completer() const
+{
+    return c;
+}
+//! [3]
+
+//! [4]
+void TextEdit::insertCompletion(const QString &completion)
+{
+    if (c->widget() != this)
+        return;
+    QTextCursor tc = textCursor();
+    int extra = completion.length() - c->completionPrefix().length();
+    tc.movePosition(QTextCursor::Left);
+    tc.movePosition(QTextCursor::EndOfWord);
+    tc.insertText(completion.right(extra));
+    setTextCursor(tc);
+}
+//! [4]
+
+//! [5]
+QString TextEdit::textUnderCursor() const
+{
+    QTextCursor tc = textCursor();
+    tc.select(QTextCursor::WordUnderCursor);
+    return tc.selectedText();
+}
+//! [5]
+
+//! [6]
+void TextEdit::focusInEvent(QFocusEvent *e)
+{
+    if (c)
+        c->setWidget(this);
+    QTextEdit::focusInEvent(e);
+}
+//! [6]
+
+//! [7]
+void TextEdit::keyPressEvent(QKeyEvent *e)
+{
+    if (c && c->popup()->isVisible()) {
+        // The following keys are forwarded by the completer to the widget
+       switch (e->key()) {
+       case Qt::Key_Enter:
+       case Qt::Key_Return:
+       case Qt::Key_Escape:
+       case Qt::Key_Tab:
+       case Qt::Key_Backtab:
+            e->ignore();
+            return; // let the completer do default behavior
+       default:
+           break;
+       }
+    }
+
+    const bool isShortcut = (e->modifiers().testFlag(Qt::ControlModifier) && e->key() == Qt::Key_E); // CTRL+E
+    if (!c || !isShortcut) // do not process the shortcut when we have a completer
+        QTextEdit::keyPressEvent(e);
+//! [7]
+
+//! [8]
+    const bool ctrlOrShift = e->modifiers().testFlag(Qt::ControlModifier) ||
+                             e->modifiers().testFlag(Qt::ShiftModifier);
+    if (!c || (ctrlOrShift && e->text().isEmpty()))
+        return;
+
+    static QString eow("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="); // end of word
+    const bool hasModifier = (e->modifiers() != Qt::NoModifier) && !ctrlOrShift;
+    QString completionPrefix = textUnderCursor();
+
+    if (!isShortcut && (hasModifier || e->text().isEmpty()|| completionPrefix.length() < 3
+                      || eow.contains(e->text().right(1)))) {
+        c->popup()->hide();
+        return;
+    }
+
+    if (completionPrefix != c->completionPrefix()) {
+        c->setCompletionPrefix(completionPrefix);
+        c->popup()->setCurrentIndex(c->completionModel()->index(0, 0));
+    }
+    QRect cr = cursorRect();
+    cr.setWidth(c->popup()->sizeHintForColumn(0)
+                + c->popup()->verticalScrollBar()->sizeHint().width());
+    c->complete(cr); // popup it up!
+}
+//! [8]
+

examples/widgets/tools/customcompleter/textedit.h

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+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef TEXTEDIT_H
+#define TEXTEDIT_H
+
+#include <QTextEdit>
+
+QT_BEGIN_NAMESPACE
+class QCompleter;
+QT_END_NAMESPACE
+
+//! [0]
+class TextEdit : public QTextEdit
+{
+    Q_OBJECT
+
+public:
+    TextEdit(QWidget *parent = nullptr);
+    ~TextEdit();
+
+    void setCompleter(QCompleter *c);
+    QCompleter *completer() const;
+
+protected:
+    void keyPressEvent(QKeyEvent *e) override;
+    void focusInEvent(QFocusEvent *e) override;
+
+private slots:
+    void insertCompletion(const QString &completion);
+
+private:
+    QString textUnderCursor() const;
+
+private:
+    QCompleter *c = nullptr;
+};
+//! [0]
+
+#endif // TEXTEDIT_H
+