在 javascript 中实例化 QWebChannel 对象时出现警告

Question

我有一个使用 QWebChannel 创建谷歌地图实例的小部件。当在 javascript 中实例化 QWebChannel 时，会出现几个警告：

Property 'accessibleName'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'accessibleDescription'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'layoutDirection'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'autoFillBackground'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'styleSheet'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'locale'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'windowFilePath'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'inputMethodHints'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!

Property 'accessibleName'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'accessibleDescription'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'layoutDirection'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'autoFillBackground'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'styleSheet'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'locale'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'windowFilePath'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!
Property 'inputMethodHints'' of object 'MapWindow' has no notify signal and is not constant, value updates in HTML will be broken!

var backend = null;
new QWebChannel(qt.webChannelTransport, function(channel) {
    backend = channel.objects.backend;
    backend.getRef(function(ref) {
        backend.getCenter(function(center) {
            backend.getPoints(function(points){
                map = new google.maps.Map(document.getElementById('map'), {
                   center: center[0],
                   zoom: 10
                 });
                 ...

Answer 1

QWebChannel 将分析注册对象的 q 属性，验证它们是否具有关联的信号。在您的警告消息的情况下，我推断“self”是一个 QWidget，因此它有许多 q 属性，没有关联的信号来指示错误。

鉴于以上情况，有2种解决方案：

• 通过禁用 qInstallMessageHandler 来静默错误消息：

QtCore.qInstallMessageHandler(lambda *args: None)

• 不要使用“self”作为后端，而是使用 QObject

class Backend(QObject):
    # getRef, getCenter, getPoints

self.backend = Backend(self)
self.webchannel.registerObject('backend', self.backend)