是否可以捕获全局鼠标事件

Question

I have a simple frame which is containing some buttons. My aim is that, after clicking the GetMousePosition button , getting the first mouse click position. I try to capture mouse click, even if I click outside of the running application.

This is a desktop application running on Windows. I tried some mouse events that wxwidgets provides, but I couldn't handle the next click event. I tried to find a solution with following code, but if there is some different solution, I can throw that code in the trash.

BEGIN_EVENT_TABLE(MyFrame, wxFrame)
EVT_BUTTON(BUTTON_GetPos, MyFrame::OnButtonClick)
EVT_MOUSE_EVENTS(MyFrame::OnMouseEvent)
EVT_MOUSE_CAPTURE_LOST(MyFrame::OnMouseCaptureLost)
END_EVENT_TABLE()

//some more code

void MyFrame::OnButtonClick(wxCommandEvent & WXUNUSED(event))
{
    //Start Capturing for next mouse left-click
    if (!HasCapture())
        CaptureMouse();
}


void MyFrame::OnMouseEvent(wxMouseEvent &event)
{
    if (event.LeftDown()) {
        //GetMousePosition
        if (HasCapture())
            ReleaseMouse();
    }
}

void MyFrame::OnMouseCaptureLost(wxMouseCaptureLostEvent& WXUNUSED(event))
{
}

I expect to get the mouse position, in the first left click after the button is pressed.

Answer 1

The code you posted looks like it should work. If there's a problem, it might be in the code you omitted. Anyway, here's a small example application showing the behavior you want. The underlying logic of this example is the same as the code you posted, except this example uses dynamic binding instead of event tables.

// For compilers that support precompilation, includes "wx/wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

// for all others, include the necessary headers (this file is usually all you
// need because it includes almost all "standard" wxWidgets headers)
#ifndef WX_PRECOMP
    #include "wx/wx.h"
#endif

class MyFrame : public wxFrame
{
    public:
        MyFrame(wxWindow* parent);

    protected:
        void OnButtonClick(wxCommandEvent& event);
        void OnMouseCapLost(wxMouseCaptureLostEvent& event);
        void OnLeftDown(wxMouseEvent&);

        void CleanUp();

    private:
        wxTextCtrl* m_textCtrl;
};

class MyApp : public wxApp
{
    public:
        virtual bool OnInit() wxOVERRIDE;
};

MyFrame::MyFrame(wxWindow* parent)
        :wxFrame(parent, wxID_ANY, "Demo", wxDefaultPosition, wxDefaultSize,
                 wxDEFAULT_FRAME_STYLE|wxTAB_TRAVERSAL)
{
    wxPanel* panel =  new wxPanel(this, wxID_ANY );
    wxButton* button = new wxButton(panel, wxID_ANY, "Click Me");
    m_textCtrl = new wxTextCtrl(panel, wxID_ANY, wxEmptyString,
                                 wxDefaultPosition, wxDefaultSize,
                                 wxTE_DONTWRAP|wxTE_MULTILINE|wxTE_READONLY);

    wxBoxSizer* bSizer = new wxBoxSizer(wxVERTICAL);
    bSizer->Add(button, 0, wxALL, 5);
    bSizer->Add(m_textCtrl, 1, wxALL|wxEXPAND, 5);
    panel->SetSizer(bSizer);
    Layout();

    button->Bind(wxEVT_BUTTON,&MyFrame::OnButtonClick,this);
}

void MyFrame::OnButtonClick(wxCommandEvent& event)
{
    if ( !HasCapture() )
    {
        CaptureMouse();
        m_textCtrl->AppendText("Mouse captured.\n");

        Bind(wxEVT_LEFT_DOWN, &MyFrame::OnLeftDown, this);
        Bind(wxEVT_MOUSE_CAPTURE_LOST, &MyFrame::OnMouseCapLost, this);
    }
}

void MyFrame::CleanUp()
{
    if ( HasCapture() )
        ReleaseMouse();
    Unbind(wxEVT_LEFT_DOWN, &MyFrame::OnLeftDown, this);
    Unbind(wxEVT_MOUSE_CAPTURE_LOST, &MyFrame::OnMouseCapLost, this);
}

void MyFrame::OnMouseCapLost(wxMouseCaptureLostEvent& event)
{
    m_textCtrl->AppendText("Mouse cap lost.\n");
    CleanUp();
}

void MyFrame::OnLeftDown(wxMouseEvent& event)
{
    m_textCtrl->AppendText("Click recorded.\n");
    CleanUp();
}

 bool MyApp::OnInit()
{
    MyFrame* frame = new MyFrame(NULL);
    frame->Show();
    return true;
}

wxIMPLEMENT_APP(MyApp);

I hope this helps.

edit: Here's a version using event tables as well:

// For compilers that support precompilation, includes "wx/wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

// for all others, include the necessary headers (this file is usually all you
// need because it includes almost all "standard" wxWidgets headers)
#ifndef WX_PRECOMP
    #include "wx/wx.h"
#endif

#define BUTTON_ID 101

class MyFrame : public wxFrame
{
    public:
        MyFrame(wxWindow* parent);

    protected:
        void OnButtonClick(wxCommandEvent& event);
        void OnMouseCapLost(wxMouseCaptureLostEvent& event);
        void OnMouseEvent(wxMouseEvent&);

        void CleanUp();

    private:
        wxTextCtrl* m_textCtrl;

        wxDECLARE_EVENT_TABLE();
};

class MyApp : public wxApp
{
    public:
        virtual bool OnInit() wxOVERRIDE;
};

wxBEGIN_EVENT_TABLE(MyFrame, wxFrame)
    EVT_BUTTON(BUTTON_ID, MyFrame::OnButtonClick)
    EVT_MOUSE_EVENTS(MyFrame::OnMouseEvent)
    EVT_MOUSE_CAPTURE_LOST(MyFrame::OnMouseCapLost)
wxEND_EVENT_TABLE()

MyFrame::MyFrame(wxWindow* parent)
        :wxFrame(parent, wxID_ANY, "Demo", wxDefaultPosition, wxDefaultSize,
                 wxDEFAULT_FRAME_STYLE|wxTAB_TRAVERSAL)
{
    wxPanel* panel =  new wxPanel(this, wxID_ANY );
    wxButton* button = new wxButton(panel, BUTTON_ID, "Click Me");
    m_textCtrl = new wxTextCtrl(panel, wxID_ANY, wxEmptyString,
                                 wxDefaultPosition, wxDefaultSize,
                                 wxTE_DONTWRAP|wxTE_MULTILINE|wxTE_READONLY);

    wxBoxSizer* bSizer = new wxBoxSizer(wxVERTICAL);
    bSizer->Add(button, 0, wxALL, 5);
    bSizer->Add(m_textCtrl, 1, wxALL|wxEXPAND, 5);
    panel->SetSizer(bSizer);
    Layout();
}

void MyFrame::OnButtonClick(wxCommandEvent& event)
{
    if ( !HasCapture() )
    {
        CaptureMouse();
        m_textCtrl->AppendText("Mouse captured.\n");
    }
}

void MyFrame::CleanUp()
{
    if ( HasCapture() )
        ReleaseMouse();
}

void MyFrame::OnMouseCapLost(wxMouseCaptureLostEvent& event)
{
    m_textCtrl->AppendText("Mouse cap lost.\n");
    CleanUp();
}

void MyFrame::OnMouseEvent(wxMouseEvent& event)
{
    if( HasCapture() && event.LeftIsDown() )
    {
        m_textCtrl->AppendText("Click recorded.\n");
        CleanUp();
    }

}

 bool MyApp::OnInit()
{
    MyFrame* frame = new MyFrame(NULL);
    frame->Show();
    return true;
}

wxIMPLEMENT_APP(MyApp);