wxWidgets中的线程

Question

我使用wxWidgets,我调用函数需要很长时间才能继续.我想在后台做.

我怎样才能做到这一点？

感谢帮助

Answer 1

我已经使用wxWidgets中的线程处理了几乎所有这里描述的方式,我可以说使用自定义事件,虽然最初有点复杂,但从长远来看会让你头疼.(wxMessageQueue类非常好,但是当我使用它时,我发现它泄漏了;虽然我在大约一年内没有检查过它.)

一个基本的例子:

MyFrm.cpp

#include "MyThread.h"

BEGIN_EVENT_TABLE(MyFrm,wxFrame)
    EVT_COMMAND(wxID_ANY, wxEVT_MYTHREAD, MyFrm::OnMyThread)
END_EVENT_TABLE()
void MyFrm::PerformCalculation(int someParameter){
    //create the thread
    MyThread *thread = new Mythread(this, someParameter);
    thread->Create();
    thread->Run();
    //Don't worry about deleting the thread, there are two types of wxThreads 
    //and this kind deletes itself when it's finished.
}
void MyFrm::OnMyThread(wxCommandEvent& event)
{
    unsigned char* temp = (unsigned char*)event.GetClientData();
    //do something with temp, which holds unsigned char* data from the thread
    //GetClientData() can return any kind of data you want, but you have to cast it.
    delete[] temp; 
}    

MyThread.h

#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <wx/thread.h>
#include <wx/event.h>

BEGIN_DECLARE_EVENT_TYPES()
    DECLARE_EVENT_TYPE(wxEVT_MYTHREAD, -1)
END_DECLARE_EVENT_TYPES()

class MyThread : public wxThread
{
    public:
        MyThread(wxEvtHandler* pParent, int param);
    private:
        int m_param;
        void* Entry();
    protected:
        wxEvtHandler* m_pParent;
};
#endif 

MyThread.cpp

#include "MyThread.h"
DEFINE_EVENT_TYPE(wxEVT_MYTHREAD)
MyThread::MyThread(wxEvtHandler* pParent, int param) : wxThread(wxTHREAD_DETACHED), m_pParent(pParent)
{
    //pass parameters into the thread
m_param = param;
}
void* MyThread::Entry()
{
    wxCommandEvent evt(wxEVT_MYTHREAD, GetId());
    //can be used to set some identifier for the data
    evt.SetInt(r); 
    //whatever data your thread calculated, to be returned to GUI
    evt.SetClientData(data); 
    wxPostEvent(m_pParent, evt);
    return 0;
}

我觉得这比wiki提供的更加清晰,简洁.显然,我遗漏了有关实际启动应用程序的代码(wx约定会使MyApp.cpp)以及任何其他非线程相关的代码.

Answer 2

如果你只是需要让一些东西在后台工作直到它完成——如果你愿意的话，就可以忘记，像这样：

// warning: off the top of my head ;-)
class MyThread
  : public wxThread
{
public:
  MyThread() : wxThread(wxTHREAD_DETACHED)
  {
    if(wxTHREAD_NO_ERROR == Create()) {
      Run();
    }
  }
protected:
  virtual ExitCode Entry()
  {
    // do something here that takes a long time
    // it's a good idea to periodically check TestDestroy()
    while(!TestDestroy() && MoreWorkToDo()) {
      DoSaidWork();
    }
    return static_cast<ExitCode>(NULL);
  }
};

MyThread* thd = new MyThread(); // auto runs & deletes itself when finished