阻塞等待异步Qt信号

问题描述

我知道，下面有一些类似的问题，但我找不到一个具体的答案帮助我。所以这里是我的问题：

我工作在一个应用程序，启动时做一些gui-initialisations。我要做的事情之一是调用

  NetworkConfigurationManager :: updateConfigurations（）
  

这是一个异步调用，它发出 updateCompleted（）完成。问题是，所有其他gui-initialisations必须等待，直到 updateConfigurations（）完成。

所以我可以这样做：

  MyApp :: MyApp（QWidget * parent）：.... 
 {
 doSomeInits（）; 
 //现在连接我们等待的信号
 connect（configManager，SIGNAL（updateCompleted（）），this，SLOT（networkConfigurationUpdated（））; 
 configManager-> updateConfigurations（）; //调用异步函数
} 
 
 void MyApp :: networkConfigurationUpdated（）
 {
 doSomething（）; 
 doRemainingInitsThatHadToWaitForConfigMgr（）; 
} 
  

分割初始化似乎不是一个好办法。我认为它使代码更难读 - 应该保持在一起。另一件事是：因为 updateConfiguration（）是异步，用户将能够使用GUI，这不会给他任何信息但是，因为我们正在等待 updateCompleted（）。

在应用程序继续之前， updateCompleted（）信号？

like：

  MyApp :: MyApp（QWidget * parent）：.... 
 {
 doSomeInits 
 //现在连接我们等待的信号
 connect（configManager，SIGNAL（updateCompleted（）），this，SLOT（doSomething（））） 
 ???? //等到doSomething（）完成。 
 doRemainingInitsThatHadToWaitForConfigMgr（）; 
} 
  

在某些API中有异步函数的阻塞替代， 。

我很感激任何帮助。感谢！

解决方案

  MyApp :: MyApp（QWidget * parent）：.... 
 {
 doSomeInits（）; 
 {
 QEventLoop loop; 
 loop.connect（configManager，SIGNAL（updateCompleted（）），SLOT（quit（）））; 
 configManager-> updateConfigurations（）; 
 loop.exec（）; 
} 
 doReaminingInitsThatHadToWaitForConfigMgr（）;注意：我没有事件编译这段代码，但IMHO本地QEventLoop是一种方式。
 
I know, there are some similar questions to the following out there, but I couldn't find a concrete answer that helps me. So here's my problem:

I work on an application that does some gui-initialisations on start up. One of the things I have to do, is calling
NetworkConfigurationManager::updateConfigurations ()
This is a asynchronous call, which emits the updateCompleted() signal, when it is finished. The problem is, that all my other gui-initialisations have to wait until the updateConfigurations() is finished. 
So what I could do would be something like this:
MyApp::MyApp(QWidget *parent) : ....
{
   doSomeInits();
   //Now connect the signal we have to wait for
   connect(configManager, SIGNAL(updateCompleted()), this, SLOT(networkConfigurationUpdated()));
   configManager->updateConfigurations(); //call the async function
}

void MyApp::networkConfigurationUpdated()
{
   doSomething();
   doRemainingInitsThatHadToWaitForConfigMgr();
}
To split up the initialisation doesn't seem a good way to me. I think it makes the code much harder to read - inits should remain together. The other thing is: Because updateConfiguration() is asynchronous, the user will be able to use the GUI, which doesn't give him any information yet, cause we are waiting for updateCompleted().
So is there a way to wait for the updateCompleted() signal, before the application continues?
like:
MyApp::MyApp(QWidget *parent) : ....
{
   doSomeInits();
   //Now connect the signal we have to wait for
   connect(configManager, SIGNAL(updateCompleted()), this, SLOT(doSomething()));
   ???? //wait until doSomething() is done.
   doRemainingInitsThatHadToWaitForConfigMgr();
}
In some APIs there are blocking alternatives to asynchronous functions, but not in this case.
I appreciate any help. Thanks!
 解决方案 
MyApp::MyApp(QWidget *parent) : ....
{
    doSomeInits();
    {
        QEventLoop loop;
        loop.connect(configManager, SIGNAL(updateCompleted()), SLOT(quit()));
        configManager->updateConfigurations();
        loop.exec();
    }
    doReaminingInitsThatHadToWaitForConfigMgr();
}
Note: I haven't event compiled this snippet, but IMHO local QEventLoop is a way to go.
                        
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