Integrating C++ with QML

爱被打了一巴掌 2022-07-24 03:20 202阅读 0赞

Qt quick中C++与QML的整合。

出自：  
[http://www.ics.com/blog/integrating-c-qml][http_www.ics.com_blog_integrating-c-qml]

![这里写图片描述][20160511231255555]

把大象装冰箱里总共分四步：  
**1. 定义一个类，继承自QObject。**  
**2. 在定义的类中声明Q\_OBJECT，这样可以支持signals 和slots和meta-object system。**  
**3. 通过Q\_PROPERTY定义一些属性。**  
**4. 在main程序中调用qmlRegisterType() 注册。**

**keygenerator.h**

#ifndef KEYGENERATOR_H
 #define KEYGENERATOR_H
 
 #include <QObject>
 #include <QString>
 #include <QStringList>
 
 // Simple QML object to generate SSH key pairs by calling ssh-keygen.
 class KeyGenerator : public QObject { Q_OBJECT Q_PROPERTY(QString type READ type WRITE setType NOTIFY typeChanged) Q_PROPERTY(QStringList types READ types NOTIFY typesChanged) Q_PROPERTY(QString filename READ filename WRITE setFilename NOTIFY filenameChanged) Q_PROPERTY(QString passphrase READ filename WRITE setPassphrase NOTIFY passphraseChanged) public: KeyGenerator(); ~KeyGenerator(); QString type(); void setType(const QString &t); QStringList types(); QString filename(); void setFilename(const QString &f); QString passphrase(); void setPassphrase(const QString &p); public slots: void generateKey(); signals: void typeChanged(); void typesChanged(); void filenameChanged(); void passphraseChanged(); void keyGenerated(bool success); private: QString _type; QString _filename; QString _passphrase; QStringList _types; }; #endif

**keygenerator.cpp**

#include <QFile>
 #include <QProcess>
 #include "KeyGenerator.h"
 
 KeyGenerator::KeyGenerator()
 : _type("rsa"), _types{
 "dsa", "ecdsa", "rsa", "rsa1"}
 {
 }
 
 KeyGenerator::~KeyGenerator()
 {
 }
 
 QString KeyGenerator::type()
 {
 return _type;
 }
 
 void KeyGenerator::setType(const QString &t)
 {
 // Check for valid type.
 if (!_types.contains(t))
 return;
 
 if (t != _type) {
 _type = t;
 emit typeChanged();
 }
 }
 
 QStringList KeyGenerator::types()
 {
 return _types;
 }
 
 QString KeyGenerator::filename()
 {
 return _filename;
 }
 
 void KeyGenerator::setFilename(const QString &f)
 {
 if (f != _filename) {
 _filename = f;
 emit filenameChanged();
 }
 }
 
 QString KeyGenerator::passphrase()
 {
 return _passphrase;
 }
 
 void KeyGenerator::setPassphrase(const QString &p)
 {
 if (p != _passphrase) {
 _passphrase = p;
 emit passphraseChanged();
 }
 }
 
 void KeyGenerator::generateKey()
 {
 // Sanity check on arguments
 if (_type.isEmpty() or _filename.isEmpty() or
 (_passphrase.length() > 0 and _passphrase.length() < 5)) {
 emit keyGenerated(false);
 return;
 }
 
 // Remove key file if it already exists
 if (QFile::exists(_filename)) {
 QFile::remove(_filename);
 }
 
 // Execute ssh-keygen -t type -N passphrase -f keyfileq
 QProcess *proc = new QProcess;
 QString prog = "ssh-keygen";
 QStringList args{
 "-t", _type, "-N", _passphrase, "-f", _filename};
 proc->start(prog, args);
 proc->waitForFinished();
 emit keyGenerated(proc->exitCode() == 0);
 delete proc;
 }

**main.cpp**

#include <QApplication>
 #include <QObject>
 #include <QQmlComponent>
 #include <QQmlEngine>
 #include <QQuickWindow>
 #include <QSurfaceFormat>
 #include "KeyGenerator.h"
 
 // Main wrapper program.
 // Special handling is needed when using Qt Quick Controls for the top window.
 // The code here is based on what qmlscene does.
 
 int main(int argc, char ** argv)
 {
 QApplication app(argc, argv);
 
 // Register our component type with QML.
 qmlRegisterType<KeyGenerator>("com.ics.demo", 1, 0, "KeyGenerator");
 
 int rc = 0;
 
 QQmlEngine engine;
 QQmlComponent *component = new QQmlComponent(&engine);
 
 QObject::connect(&engine, SIGNAL(quit()), QCoreApplication::instance(), SLOT(quit()));
 
 component->loadUrl(QUrl("qrc:/main.qml"));
 
 if (!component->isReady() ) {
 qWarning("%s", qPrintable(component->errorString()));
 return -1;
 }
 
 QObject *topLevel = component->create();
 QQuickWindow *window = qobject_cast<QQuickWindow *>(topLevel);
 
 QSurfaceFormat surfaceFormat = window->requestedFormat();
 window->setFormat(surfaceFormat);
 window->show();
 
 rc = app.exec();
 
 delete component;
 return rc;
 }

**main.qml**

// SSH key generator UI
 
 import QtQuick 2.1
 import QtQuick.Controls 1.0
 import QtQuick.Layouts 1.0
 import QtQuick.Dialogs 1.0
 import com.ics.demo 1.0
 
 ApplicationWindow {
 title: qsTr("SSH Key Generator")
 
 statusBar: StatusBar {
 RowLayout {
 Label {
 id: status
 }
 }
 }
 
 width: 369
 height: 166
 
 ColumnLayout {
 x: 10
 y: 10
 
 // Key type
 RowLayout {
 Label {
 text: qsTr("Key type:")
 }
 ComboBox {
 id: combobox
 Layout.fillWidth: true
 model: keygen.types
 currentIndex: 2
 }
 }
 
 // Filename
 RowLayout {
 Label {
 text: qsTr("Filename:")
 }
 TextField {
 id: filename
 implicitWidth: 200
 onTextChanged: updateStatusBar()
 }
 Button {
 text: qsTr("&Browse...")
 onClicked: filedialog.visible = true
 }
 }
 
 // Passphrase
 RowLayout {
 Label {
 text: qsTr("Pass phrase:")
 }
 TextField {
 id: passphrase
 Layout.fillWidth: true
 echoMode: TextInput.Password
 onTextChanged: updateStatusBar()
 }
 
 }
 
 // Confirm Passphrase
 RowLayout {
 Label {
 text: qsTr("Confirm pass phrase:")
 }
 TextField {
 id: confirm
 Layout.fillWidth: true
 echoMode: TextInput.Password
 onTextChanged: updateStatusBar()
 }
 }
 
 // Buttons: Generate, Quit
 RowLayout {
 Button {
 id: generate
 text: qsTr("&Generate")
 onClicked: keygen.generateKey()
 }
 Button {
 text: qsTr("&Quit")
 onClicked: Qt.quit()
 }
 }
 
 }
 
 FileDialog {
 id: filedialog
 title: qsTr("Select a file")
 selectMultiple: false
 selectFolder: false
 nameFilters: [ "All files (*)" ]
 selectedNameFilter: "All files (*)"
 onAccepted: {
 filename.text = fileUrl.toString().replace("file://", "")
 }
 }
 
 KeyGenerator {
 id: keygen
 filename: filename.text
 passphrase: passphrase.text
 type: combobox.currentText
 onKeyGenerated: {
 if (success) {
 status.text = qsTr('Key generation succeeded.')
 } else {
 status.text = qsTr('Key generation failed')
 }
 }
 }
 
 function updateStatusBar() { 
 if (passphrase.text != confirm.text) {
 status.text = qsTr('Pass phrase does not match.')
 generate.enabled = false
 } else if (passphrase.text.length > 0 && passphrase.text.length < 5) {
 status.text = qsTr('Pass phrase too short.')
 generate.enabled = false
 } else if (filename.text == "") {
 status.text = qsTr('Enter a filename.')
 generate.enabled = false
 } else {
 status.text = ""
 generate.enabled = true
 }
 }
 
 Component.onCompleted: updateStatusBar()
 }

**.pro文件**

TEMPLATE = app
    
    QT += qml quick
    CONFIG += c++11
    
    QT += widgets
    
    SOURCES += main.cpp \
        keygenerator.cpp
    
    RESOURCES += qml.qrc
    
    # Additional import path used to resolve QML modules in Qt Creator's code model
    QML_IMPORT_PATH =
    
    # Default rules for deployment.
    include(deployment.pri)
    
    HEADERS += \
        keygenerator.h

[http_www.ics.com_blog_integrating-c-qml]: http://www.ics.com/blog/integrating-c-qml
[20160511231255555]: /images/20220722/48b8f3cea03e4421ae7f98cc277711bd.png