[Python自学] PyQT5-Web控件、与JavaScript交互

一、使用WEB控件打开网页

要使用PyQt5的WebEngine，需要安装PyQtWebEngine（pyqt5 5.11版本之前可以直接from PyQt5.QtWebEngineWidgets import *）

pip install PyQtWebEngine

Demo：

import sys

# 使用调色板等
from PyQt5.QtCore import Qt, QUrl
from PyQt5.QtGui import QIcon
# 导入QT,其中包含一些常量，例如颜色等
# 导入常用组件
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit
from PyQt5.QtWidgets import QMdiArea, QMdiSubWindow
from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineView


class DemoWin(QMainWindow):
    count = 0

    def __init__(self):
        super(DemoWin, self).__init__()
        self.initUI()

    def initUI(self):
        # 将窗口设置为动图大小
        self.resize(1000, 800)
        self.browser = QWebEngineView()
        self.browser.load(QUrl('https://www.jd.com'))
        self.setCentralWidget(self.browser)
 
        # 添加窗口标题
        self.setWindowTitle("WebEngineDemo")


if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon("images/icon.ico"))
    # 创建一个主窗口
    mainWin = DemoWin()
    # 显示
    mainWin.show()
    # 主循环
    sys.exit(app.exec_())

实现效果：

二、加载本地web页面

import sys
import os

# 使用调色板等
from PyQt5.QtCore import Qt, QUrl
from PyQt5.QtGui import QIcon
# 导入QT,其中包含一些常量，例如颜色等
# 导入常用组件
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit
from PyQt5.QtWidgets import QMdiArea, QMdiSubWindow
from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineView


class DemoWin(QMainWindow):
    count = 0

    def __init__(self):
        super(DemoWin, self).__init__()
        self.initUI()

    def initUI(self):
        # 将窗口设置为动图大小
        self.resize(500, 500)
        self.browser = QWebEngineView()
        url = os.getcwd() + '/test.html'
        self.browser.load(QUrl.fromLocalFile(url))
        self.setCentralWidget(self.browser)

        # 添加窗口标题
        self.setWindowTitle("WebEngineDemo")


if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon("images/icon.ico"))
    # 创建一个主窗口
    mainWin = DemoWin()
    # 显示
    mainWin.show()
    # 主循环
    sys.exit(app.exec_())

效果：

三、嵌入HTML

前面我们都是使用的QWebEngineView控件来打开Web页面或加载本地Html页面，除了这种方式，我们也可以直接将Html代码嵌入到窗口中。

import sys
import os

# 使用调色板等
from PyQt5.QtCore import Qt, QUrl
from PyQt5.QtGui import QIcon
# 导入QT,其中包含一些常量，例如颜色等
# 导入常用组件
from PyQt5.QtWidgets import QApplication, QMainWindow, QTextEdit
from PyQt5.QtWidgets import QMdiArea, QMdiSubWindow
from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineView


class DemoWin(QMainWindow):
    count = 0

    def __init__(self):
        super(DemoWin, self).__init__()
        self.initUI()

    def initUI(self):
        # 将窗口设置为动图大小
        self.resize(500, 500)
        self.browser = QWebEngineView()
        # 直接将html代码嵌入控件
        self.browser.setHtml('''
        <!DOCTYPE html>
        <html lang="en">
        <head>
            <meta charset="UTF-8">
            <title>TEST Page</title>
        </head>
        <body>
        <h1>TEST</h1>
        <h2>TEST</h2>
        <h3>TEST</h3>
        <h4>TEST</h4>
        <h5>TEST</h5>
        <h6>TEST</h6>
        </body>
        </html>
        ''')

        self.setCentralWidget(self.browser)

        # 添加窗口标题
        self.setWindowTitle("WebEngineDemo")


if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon("images/icon.ico"))
    # 创建一个主窗口
    mainWin = DemoWin()
    # 显示
    mainWin.show()
    # 主循环
    sys.exit(app.exec_())

效果：

四、PyQt5调用html页面中的JS代码

编写一个Html页面，其中包含JS代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>TEST Page</title>
    <script>
        function fullName(value) {
            alert(value);
            var firstname = document.getElementById('firstname').value;
            var lastname = document.getElementById('lastname').value;

            var fullname = firstname + " " + lastname;
            document.getElementById('fullname').value = fullname;
            return fullname;
        }
    </script>
</head>
<body>
<form>
    <label>First Name:</label>
    <input name="firstname" id="firstname">
    <br>
    <label>Last Name:</label>
    <input name="lastname" id="lastname">
    <br>
    <label>Full Name:</label>
    <input name="fullname" id="fullname">
</form>
</body>
</html>

编写PyQt5代码调用页面中的JS代码：

import sys
import os

# 使用调色板等
from PyQt5.QtCore import Qt, QUrl
from PyQt5.QtGui import QIcon
# 导入QT,其中包含一些常量，例如颜色等
# 导入常用组件
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWebEngineWidgets import QWebEngineView


class DemoWin(QWidget):
    count = 0

    def __init__(self):
        super(DemoWin, self).__init__()
        self.initUI()

    def initUI(self):
        # 将窗口设置为动图大小
        self.resize(500, 200)
        self.browser = QWebEngineView()
        url = os.getcwd() + '/test.html'
        # 加载test.html
        self.browser.load(QUrl.fromLocalFile(url))

        # 定义一个按钮，在槽函数中调用JS函数
        self.addBtn = QPushButton("获取全名")
        self.addBtn.clicked.connect(self.getFullName)

        layout = QVBoxLayout()
        layout.addWidget(self.browser)
        layout.addWidget(self.addBtn)
        self.setLayout(layout)

        # 添加窗口标题
        self.setWindowTitle("JSDemo")

    def getFullName(self):
        # 传递参数value到JS函数
        value = "Hello World"
        # 调用JS中的fullName函数
        self.browser.page().runJavaScript('fullName("' + value + '");')


if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon("images/icon.ico"))
    # 创建一个主窗口
    mainWin = DemoWin()
    # 显示
    mainWin.show()
    # 主循环
    sys.exit(app.exec_())

实现效果：

五、Html页面中的JS代码调用Python代码

在HTML的JS代码中调用PyQt5的代码比较繁琐，如下代码所示。

HTML代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>TEST Page</title>
    <script src="./qwebchannel.js"></script>
    <script language="javascript">
        // 用于PyQt5代码返回值后调用
        function callback(result) {
            alert('计算结果:' + result);
        }

        document.addEventListener("DOMContentLoaded", function () {
            // 这里面的channel就是PyQt5传递过来的channel对象，其中包含了可供调用的obj对象（一个Factorial类对象）
            new QWebChannel(qt.webChannelTransport, function (channel) {
                // 从channel中获取到我们注册到channel中的Factorial类对象
                window.obj = channel.objects.obj;
            });
        });

        function onFactorial() {
            // 如果获取到了Factorial对象
            if (window.obj) {
                // 获取输入框中的数字
                var n = parseInt(document.getElementById('n').value);
                // 调用Factorial类对象中的槽函数factorial(n),并且指定一个异步调用的callback函数，当factorial返回时
                // 自动调用callback
                window.obj.factorial(n, callback);
            }
        }
    </script>
</head>
<body>
<form>
    <label>请输入N:</label>
    <input type="text" id="n">
    <br>
    <input type="button" value="计算阶乘" onclick="onFactorial()">
</form>
</body>
</html>

注意，这里需要导入一个PyQt5提供的js文件：qwebchannel.js，内容如下：

/****************************************************************************
**
** Copyright (C) 2016 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: https://www.qt.io/licensing/
**
** This file is part of the QtWebChannel module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

"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
    };
}

qwebchannel.js

PyQt5代码：

import sys
import os

# 使用调色板等
from PyQt5.QtCore import Qt, QUrl, QObject, pyqtSlot
from PyQt5.QtGui import QIcon
# 导入QT,其中包含一些常量，例如颜色等
# 导入常用组件
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtWebEngineWidgets import QWebEngineView
# 导入QWebChannel
from PyQt5.QtWebChannel import QWebChannel


# 定义一个类，其中包含一个槽函数，供JS代码调用来计算阶乘
class Factorial(QObject):
    # 将其定义为一个槽函数，参数类型为int，返回值类型为int
    @pyqtSlot(int, result=int)
    def factorial(self, n):
        if n == 0 or n == 1:
            return 1
        else:
            return self.factorial(n - 1) * n


# 定义一个channel全局对象，用于注册一些对象提供给html页面中的JS代码调用
channel = QWebChannel()
# 定义一个对象，其中包含槽函数，注册到channel可以传递给JS代码
factorial = Factorial()


class DemoWin(QWidget):
    count = 0

    def __init__(self):
        super(DemoWin, self).__init__()
        self.initUI()

    def initUI(self):
        # 将窗口设置为动图大小
        self.resize(500, 200)
        self.browser = QWebEngineView()
        url = os.getcwd() + '/test.html'
        # 加载test.html
        self.browser.load(QUrl.fromLocalFile(url))

        # 将factorial对象注册到channel中，名字为obj，JS中使用这个名字来调用函数
        channel.registerObject("obj", factorial)
        # 将channel传递给html中的JS
        self.browser.page().setWebChannel(channel)

        layout = QVBoxLayout()
        layout.addWidget(self.browser)
        self.setLayout(layout)

        # 添加窗口标题
        self.setWindowTitle("JSDemo")

    def getFullName(self):
        # 传递参数value到JS函数
        value = "Hello World"
        # 调用JS中的fullName函数
        self.browser.page().runJavaScript('fullName("' + value + '");')


if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon("images/icon.ico"))
    # 创建一个主窗口
    mainWin = DemoWin()
    # 显示
    mainWin.show()
    # 主循环
    sys.exit(app.exec_())

实现效果：

===

posted @ 2020-06-17 10:50 风间悠香阅读(8428) 评论(0) 编辑收藏举报

风间悠香

风间悠香的笔记本

[Python自学] PyQT5-Web控件、与JavaScript交互

一、使用WEB控件打开网页

二、加载本地web页面

三、嵌入HTML

四、PyQt5调用html页面中的JS代码

五、Html页面中的JS代码调用Python代码