PyQt5 JavaScript调用PyQt代码

JavaScript调用PyQt代码

JavaScript调用PyQt代码,是指PyQt可以与加载的Web页面进行双向的数据交互。
1.创建QWebChannel对象：
创建QWebChannel对象，注册一个需要桥接的对象，以便Web页面的JavaScript使用。其核心代码如下：

channel = QWebChannel()
myObj = MySharedObject()
channel.registerObject(“bridge”, myObj)
view = QWebEngineView()
view.page.setWebChannel(channel)
2.创建共享数据的PyQt对象
创建的共享数据对象需要继承QWidget或QObject类，其核心代码如下：

from PyQt5.QtCore import QObject
from PyQt5.QtCore import pyqtProperty
from PyQt5.QtWidgets import QWidget, QMessageBox

class MySharedObject(QWidget):

    def __init__(self):
        super(MySharedObject, self).__init__()

    def _getStrValue(self):
        return '100'
    
    def _setStrValue(self, str):
        print('获得页面参数：%s' % str)
        QMessageBox.information(self, "Information", "获得页面参数：%s" %str)
    
    # 需要定义对外发布的方法
    strValue = pyqtProperty(str, fget=_setStrValue, fset=_setStrValue)
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PyQtProperty()函数演示：

from PyQt5.QtCore import QObject, pyqtProperty

class MyObject(QObject):
    def __init__(self, inVal=20):
        self.val = inVal

    def readVal(self):
        print('readVal=%s' % self.val)
        return self.val
    
    def setVal(self, val):
        print('setVal=%s' % val)
        self.val = val
    
    ppVal = pyqtProperty(int, readVal, setVal)
    

if __name__ == "__main__":
    obj = MyObject()
    print('\n#1')
    obj.ppVal = 10
    print('\n#2')
    print('obj.ppVal=%s' % obj.ppVal)
    print('obj.readVal()=%s' % obj.readVal())

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JavaScript调用PyQt代码演示

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout
from PyQt5.QtWebEngineWidgets import QWebEngineView
from PyQt5.QtCore import QUrl
from MySharedObject import MySharedObject
from PyQt5.QtWebChannel import QWebChannel

# 创建一个应用实例
app = QApplication(sys.argv)
win = QWidget()
win.setWindowTitle("Web页面中的JavaScript与QWebEngineView交互")

layout = QVBoxLayout()
win.setLayout(layout)

# 创建一个QWebEngineView对象
view = QWebEngineView()
htmlUrl = 'http://127.0.0.1:8848/webdemo/client_index.html'
view.load(QUrl(htmlUrl))

# 创建一个QWebChannel对象，用来传递PyQt的参数到JavaScript
channel = QWebChannel()
myObj = MySharedObject()
channel.registerObject("bridge", myObj)
view.page().setWebChannel(channel)

# 把QWebEngineView控件和button控件加载到layout布局中
layout.addWidget(view)

win.show()
sys.exit(app.exec_())
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HBuilder创建web项目：

DOCTYPE html>
 <html>
    <head>
      <title>A Demo Pagetitle>
      <meta charset="UTF-8">
      <script src="./qwebchannel.js">script>
      <script language="javascript">
        function completeAndReturnName() {
          var fname = document.getElementById('fname').value;
          var lname = document.getElementById('lname').value;
          var full = fname + ' ' + lname;

          document.getElementById('fullname').value = full;
          document.getElementById('submit-btn').style.display = 'block';

          return full;
        }
                      
        document.addEventListener("DOMContentLoaded", function () {
                 	
        	new QWebChannel( qt.webChannelTransport, function(channel) {
	        	//alert('111 channel=' + channel )
	        	
	            window.bridge = channel.objects.bridge;
	            alert('bridge='+bridge+'\n从pyqt传来的参数=' + window.bridge.strValue ) ;
	            
	        });
        });
        
	      function onShowMsgBox() {
	        //alert('window.bridge=' + window.bridge);
	        
	        if ( window.bridge) {
	        	//alert('bridge.strValue=' + window.bridge.strValue ) ;
	            //bridge.sayHello('999')
	            var fname = document.getElementById('fname').value;
	            window.bridge.strValue = fname;
	            
	            
	        }
        	
        }
	          
      
      script>     
    head>

    <body>
      <form>
        <label for="姓名">user name:label>
        <input type="text" name="fname" id="fname">input>
        <br />
        <input type="button" value="传递参数到pyqt" onclick="onShowMsgBox()">
        <input type="reset" value='重置'/>
      form>
    body>
  html>
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页面中引入的qwebchannel.js 脚本，这个脚本是Qt官方提供的：

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2014 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtWebChannel module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

"use strict";

var QWebChannelMessageTypes = {
    signal: 1,
    propertyUpdate: 2,
    init: 3,
    idle: 4,
    debug: 5,
    invokeMethod: 6,
    connectToSignal: 7,
    disconnectFromSignal: 8,
    setProperty: 9,
    response: 10,
};

var QWebChannel = function(transport, initCallback)
{
    if (typeof transport !== "object" || typeof transport.send !== "function") {
        console.error("The QWebChannel expects a transport object with a send function and onmessage callback property." +
                      " Given is: transport: " + typeof(transport) + ", transport.send: " + typeof(transport.send));
        return;
    }

    var channel = this;
    this.transport = transport;

    this.send = function(data)
    {
        if (typeof(data) !== "string") {
            data = JSON.stringify(data);
        }
        channel.transport.send(data);
    }

    this.transport.onmessage = function(message)
    {
        var data = message.data;
        if (typeof data === "string") {
            data = JSON.parse(data);
        }
        switch (data.type) {
            case QWebChannelMessageTypes.signal:
                channel.handleSignal(data);
                break;
            case QWebChannelMessageTypes.response:
                channel.handleResponse(data);
                break;
            case QWebChannelMessageTypes.propertyUpdate:
                channel.handlePropertyUpdate(data);
                break;
            default:
                console.error("invalid message received:", message.data);
                break;
        }
    }

    this.execCallbacks = {};
    this.execId = 0;
    this.exec = function(data, callback)
    {
        if (!callback) {
            // if no callback is given, send directly
            channel.send(data);
            return;
        }
        if (channel.execId === Number.MAX_VALUE) {
            // wrap
            channel.execId = Number.MIN_VALUE;
        }
        if (data.hasOwnProperty("id")) {
            console.error("Cannot exec message with property id: " + JSON.stringify(data));
            return;
        }
        data.id = channel.execId++;
        channel.execCallbacks[data.id] = callback;
        channel.send(data);
    };

    this.objects = {};

    this.handleSignal = function(message)
    {
        var object = channel.objects[message.object];
        if (object) {
            object.signalEmitted(message.signal, message.args);
        } else {
            console.warn("Unhandled signal: " + message.object + "::" + message.signal);
        }
    }

    this.handleResponse = function(message)
    {
        if (!message.hasOwnProperty("id")) {
            console.error("Invalid response message received: ", JSON.stringify(message));
            return;
        }
        channel.execCallbacks[message.id](message.data);
        delete channel.execCallbacks[message.id];
    }

    this.handlePropertyUpdate = function(message)
    {
        for (var i in message.data) {
            var data = message.data[i];
            var object = channel.objects[data.object];
            if (object) {
                object.propertyUpdate(data.signals, data.properties);
            } else {
                console.warn("Unhandled property update: " + data.object + "::" + data.signal);
            }
        }
        channel.exec({type: QWebChannelMessageTypes.idle});
    }

    this.debug = function(message)
    {
        channel.send({type: QWebChannelMessageTypes.debug, data: message});
    };

    channel.exec({type: QWebChannelMessageTypes.init}, function(data) {
        for (var objectName in data) {
            var object = new QObject(objectName, data[objectName], channel);
        }
        // now unwrap properties, which might reference other registered objects
        for (var objectName in channel.objects) {
            channel.objects[objectName].unwrapProperties();
        }
        if (initCallback) {
            initCallback(channel);
        }
        channel.exec({type: QWebChannelMessageTypes.idle});
    });
};

function QObject(name, data, webChannel)
{
    this.__id__ = name;
    webChannel.objects[name] = this;

    // List of callbacks that get invoked upon signal emission
    this.__objectSignals__ = {};

    // Cache of all properties, updated when a notify signal is emitted
    this.__propertyCache__ = {};

    var object = this;

    // ----------------------------------------------------------------------

    this.unwrapQObject = function(response)
    {
        if (response instanceof Array) {
            // support list of objects
            var ret = new Array(response.length);
            for (var i = 0; i < response.length; ++i) {
                ret[i] = object.unwrapQObject(response[i]);
            }
            return ret;
        }
        if (!response
            || !response["__QObject*__"]
            || response.id === undefined) {
            return response;
        }

        var objectId = response.id;
        if (webChannel.objects[objectId])
            return webChannel.objects[objectId];

        if (!response.data) {
            console.error("Cannot unwrap unknown QObject " + objectId + " without data.");
            return;
        }

        var qObject = new QObject( objectId, response.data, webChannel );
        qObject.destroyed.connect(function() {
            if (webChannel.objects[objectId] === qObject) {
                delete webChannel.objects[objectId];
                // reset the now deleted QObject to an empty {} object
                // just assigning {} though would not have the desired effect, but the
                // below also ensures all external references will see the empty map
                // NOTE: this detour is necessary to workaround QTBUG-40021
                var propertyNames = [];
                for (var propertyName in qObject) {
                    propertyNames.push(propertyName);
                }
                for (var idx in propertyNames) {
                    delete qObject[propertyNames[idx]];
                }
            }
        });
        // here we are already initialized, and thus must directly unwrap the properties
        qObject.unwrapProperties();
        return qObject;
    }

    this.unwrapProperties = function()
    {
        for (var propertyIdx in object.__propertyCache__) {
            object.__propertyCache__[propertyIdx] = object.unwrapQObject(object.__propertyCache__[propertyIdx]);
        }
    }

    function addSignal(signalData, isPropertyNotifySignal)
    {
        var signalName = signalData[0];
        var signalIndex = signalData[1];
        object[signalName] = {
            connect: function(callback) {
                if (typeof(callback) !== "function") {
                    console.error("Bad callback given to connect to signal " + signalName);
                    return;
                }

                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
                object.__objectSignals__[signalIndex].push(callback);

                if (!isPropertyNotifySignal && signalName !== "destroyed") {
                    // only required for "pure" signals, handled separately for properties in propertyUpdate
                    // also note that we always get notified about the destroyed signal
                    webChannel.exec({
                        type: QWebChannelMessageTypes.connectToSignal,
                        object: object.__id__,
                        signal: signalIndex
                    });
                }
            },
            disconnect: function(callback) {
                if (typeof(callback) !== "function") {
                    console.error("Bad callback given to disconnect from signal " + signalName);
                    return;
                }
                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
                var idx = object.__objectSignals__[signalIndex].indexOf(callback);
                if (idx === -1) {
                    console.error("Cannot find connection of signal " + signalName + " to " + callback.name);
                    return;
                }
                object.__objectSignals__[signalIndex].splice(idx, 1);
                if (!isPropertyNotifySignal && object.__objectSignals__[signalIndex].length === 0) {
                    // only required for "pure" signals, handled separately for properties in propertyUpdate
                    webChannel.exec({
                        type: QWebChannelMessageTypes.disconnectFromSignal,
                        object: object.__id__,
                        signal: signalIndex
                    });
                }
            }
        };
    }

    /**
     * Invokes all callbacks for the given signalname. Also works for property notify callbacks.
     */
    function invokeSignalCallbacks(signalName, signalArgs)
    {
        var connections = object.__objectSignals__[signalName];
        if (connections) {
            connections.forEach(function(callback) {
                callback.apply(callback, signalArgs);
            });
        }
    }

    this.propertyUpdate = function(signals, propertyMap)
    {
        // update property cache
        for (var propertyIndex in propertyMap) {
            var propertyValue = propertyMap[propertyIndex];
            object.__propertyCache__[propertyIndex] = propertyValue;
        }

        for (var signalName in signals) {
            // Invoke all callbacks, as signalEmitted() does not. This ensures the
            // property cache is updated before the callbacks are invoked.
            invokeSignalCallbacks(signalName, signals[signalName]);
        }
    }

    this.signalEmitted = function(signalName, signalArgs)
    {
        invokeSignalCallbacks(signalName, signalArgs);
    }

    function addMethod(methodData)
    {
        var methodName = methodData[0];
        var methodIdx = methodData[1];
        object[methodName] = function() {
            var args = [];
            var callback;
            for (var i = 0; i < arguments.length; ++i) {
                if (typeof arguments[i] === "function")
                    callback = arguments[i];
                else
                    args.push(arguments[i]);
            }

            webChannel.exec({
                "type": QWebChannelMessageTypes.invokeMethod,
                "object": object.__id__,
                "method": methodIdx,
                "args": args
            }, function(response) {
                if (response !== undefined) {
                    var result = object.unwrapQObject(response);
                    if (callback) {
                        (callback)(result);
                    }
                }
            });
        };
    }

    function bindGetterSetter(propertyInfo)
    {
        var propertyIndex = propertyInfo[0];
        var propertyName = propertyInfo[1];
        var notifySignalData = propertyInfo[2];
        // initialize property cache with current value
        // NOTE: if this is an object, it is not directly unwrapped as it might
        // reference other QObject that we do not know yet
        object.__propertyCache__[propertyIndex] = propertyInfo[3];

        if (notifySignalData) {
            if (notifySignalData[0] === 1) {
                // signal name is optimized away, reconstruct the actual name
                notifySignalData[0] = propertyName + "Changed";
            }
            addSignal(notifySignalData, true);
        }

        Object.defineProperty(object, propertyName, {
            configurable: true,
            get: function () {
                var propertyValue = object.__propertyCache__[propertyIndex];
                if (propertyValue === undefined) {
                    // This shouldn't happen
                    console.warn("Undefined value in property cache for property \"" + propertyName + "\" in object " + object.__id__);
                }

                return propertyValue;
            },
            set: function(value) {
                if (value === undefined) {
                    console.warn("Property setter for " + propertyName + " called with undefined value!");
                    return;
                }
                object.__propertyCache__[propertyIndex] = value;
                webChannel.exec({
                    "type": QWebChannelMessageTypes.setProperty,
                    "object": object.__id__,
                    "property": propertyIndex,
                    "value": value
                });
            }
        });

    }

    // ----------------------------------------------------------------------

    data.methods.forEach(addMethod);

    data.properties.forEach(bindGetterSetter);

    data.signals.forEach(function(signal) { addSignal(signal, false); });

    for (var name in data.enums) {
        object[name] = data.enums[name];
    }
}

//required for use with nodejs
if (typeof module === 'object') {
    module.exports = {
        QWebChannel: QWebChannel
    };
}

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在这里插入图片描述

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原文地址：https://blog.csdn.net/u013420428/article/details/128052347