python GUI库图形界面开发之PyQt5中QWebEngineView内嵌网页与Python的数据交互传参详细方法实例

 更新时间:2020-02-26 19:42:36   作者:佚名   我要评论(0)

这几天研究了下PyQt5中QWebEngineView内嵌网页与Python的数据交互,今天把实例方法与代码发布出来供大家参数
数据交互需要load进一个网页,这里我选择load进一个本地

这几天研究了下PyQt5中QWebEngineView内嵌网页与Python的数据交互,今天把实例方法与代码发布出来供大家参数

数据交互需要load进一个网页,这里我选择load进一个本地html网页:JSTest.html。

同时,QWebEngineView与外面的交互还需要Qt官方提供的一个js文件:qwebchannel.js,这个文件可以在网上下载。

JSTest.html和qwebchannel.js两个文件放在同一个目录下,我这边都是放在Python工程目录下。

qwebchannel.js:

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** 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
  };
}

Python主函数代码

import sys
import Web_UI
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QObject,pyqtProperty
from PyQt5.QtWebChannel import QWebChannel
from MySharedObject import MySharedObject
from PyQt5.QtWidgets import QApplication
import os

BASE_DIR = os.path.dirname(__file__)#获取当前文件夹的绝对路径

if __name__ == '__main__':
  app = QtWidgets.QApplication(sys.argv)
  MainWindow = QtWidgets.QFrame()
  ui = Web_UI.Ui_Form()
  ui.setupUi(MainWindow)
  ui.webView1.load(QtCore.QUrl(r""+BASE_DIR+"/JSTest.html"))

  channel = QWebChannel() ##创建一个QwebChannel对象,用于传递PyQt的参数到JavaScript
  myObj = MySharedObject()
  print(myObj.strval)

  channel.registerObject('bridge', myObj)
  ui.webView1.page().setWebChannel(channel)

  MainWindow.show()
  sys.exit(app.exec_())

继承了QWidget类的MySharedObject(Python文件)

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

class MySharedObject(QWidget):
  def __init__(self,strval = '100'):
    super(MySharedObject,self).__init__()
    self.strval = strval
  def _getStrValue(self):
    return self.strval
  def _setStrValue(self,str):
    self.strval = str
    print('获得页面参数:%s'% str)
    QMessageBox.information(self,"Infomation", '获得的页面参数%s' % str)
  #需要定义的对外发布的方法
  strValue= pyqtProperty(str,_getStrValue,_setStrValue)

页面代码HTML

<!DOCTYPE html>
    <html>
      <head>
        <meta charset="UTF-8">
        <title>A Demo Page</title>
        <script src = "qwebchannel.js"></script>

        <script language = "javascript">
          function completeAndReturnName(){
            var fname = document.getElementById('fname').value;
            var lname = document.getElementById('lname').value;
            var fullname = fname +' '+ lname;

            document.getElementById('fullname').value = fullname;
            document.getElementById('submit-btn').style.display = 'block';
            return fullname;
          }
          document.addEventListener("DOMContentLoaded",function(){
            new QWebChannel(qt.webChannelTransport, function (channel) {
              //alert('111 chanel='+channel)
              window.bridge = channel.objects.bridge;
              alert('bridge='+bridge.strValue +'\n从pyqt传来的参数='+window.bridge.strValue);
              //alert('111 chanel='+ channel.objects.strValue)
            })
          } )
          function onShowMsgBox() {
            if(window.bridge != null){
              var fname = document.getElementById('fname').value;
              window.bridge.strValue = fname; //调用对象
            }
          }
        </script>
      </head>

      <body>
        <form>
          <label id = "name">User Name:</label>
          <input type = "text" name = "fname" id = "fname"></input>
          <br />
          <input type = "button" value="传递参数到pyqt" οnclick="onShowMsgBox()"></input>
          <br />
          <input type = "reset" value="重置"></input>

        </form>
      </body>
    </html>

实现效果

本文详细介绍了PyQt5中使用QWebEngineView控件内嵌网页与Python的数据交互的方法与实例,更多关于这方面的知识请查看下面的相关链接

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