QML QObject在能够处理信号之前被销毁 [英] QML QObject destroyed before being able to process a signal

问题描述

在QML中，我使用一个C ++库，返回一个执行过程的QObject，并在完成后发出一个信号。在javascript中，我使用发出信号的 connect 方法（ success ）附加一个应该处理的匿名函数如下面的代码段所示：

  var requestResponse = apiClient.execute（reqInp）; 
 requestResponse.success.connect（function success（response）
 {
 var requestResponseJSON = JSON.parse（response.responseAsJsonString（））; 
 this.append（response.responseAsJsonString ））; 
}）;我的问题是，有时包含这个方法的QML项目在C ++代码能够被删除之前就被销毁了。完成，所以当信号被发出时，匿名函数导致错误，因为它调用未定义的方法（在我的例子中，方法 append ）。我在iOS中有一些令人讨厌的崩溃，我怀疑这是可能导致它。 
 
 
 
当创建该函数的对象被销毁时，是否有强制断开信号的方法？
解决方案
 
  var requestResponse = apiClient.execute（reqInp）; 
 function myFunction（response）
 {
 var requestResponseJSON = JSON.parse（response.responseAsJsonString（））; 
 this.append（response.responseAsJsonString（））; 
} 
 requestResponse.success.connect（myFunction）; 
 requestResponse.destroyed.disconnect（myFunction）
  
 
In QML, I'm using a C++ library that returns a QObject that does a process and emits a signal when is done. In javascript, I use the connect method of the signal being emitted (success) to attach an anonymous function that should handle the signal as the following piece of code shows:
var requestResponse = apiClient.execute(reqInp);
requestResponse.success.connect(function success(response) 
{
        var requestResponseJSON = JSON.parse(response.responseAsJsonString());
        this.append(response.responseAsJsonString());
});
My problem is that sometimes the QML item that contains this method is destroyed before the C++ code being able to complete, so when the signal is emitted, the anonymous function causes an error, because it calls methods that are undefined (in my example, the method append). I have some nasty crashes in iOS and I suspect that this is what might be causing it. 

Is there a way of force disconnection of the signal when the object that created the function is destroyed?
解决方案
var requestResponse = apiClient.execute(reqInp);
function myFunction(response) 
{
        var requestResponseJSON = JSON.parse(response.responseAsJsonString());
        this.append(response.responseAsJsonString());
}
requestResponse.success.connect(myFunction);
requestResponse.destroyed.disconnect(myFunction)


                        
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