Win32下 Qt与Lua交互使用（三）：在Lua脚本中connect Qt 对象

话接上文。笔者为了方便使用Lua，自己编写了一个Lua的类。主要代码如下：

QLua.h

 #ifndef QLUA_H
 #define QLUA_H

 // own
 #include "include/lua.hpp"

 // qt
 #include <QObject>
 #include <QFile>
 #include <QDebug>

 #include <QWidget>
 #include <QLineEdit>
 #include <QPushButton>
 #include <QMessageBox>

 class QLua : public QObject
 {
     Q_OBJECT
 public:
     QLua(QObject *parent = );
     ~QLua();

     // lua
     void init();
     void close();

     void pushFunction(QString funcName, lua_CFunction func);

     void beginModule(QString);
     void addType(QString, lua_CFunction deleteFunc);
     void moduleTypeFunction(QString, lua_CFunction);
     void endModule();

     void run(QString);
 signals:

 public slots:

 private:
     lua_State *luaState;

     bool isStartModule;
 };

 #endif // QLUA_H

QLua.cpp

 #include "qlua.h"

 QLua::QLua(QObject *parent) :
     QObject(parent)
   , luaState(NULL)
   , isStartModule(false)
 {
     init();
 }

 QLua::~QLua()
 {
     close();
 }

 void QLua::init()
 {
     luaState = luaL_newstate();
     luaL_openlibs(luaState);
 }

 void QLua::close()
 {
     if(luaState != NULL)
     {
         lua_close(luaState);
         luaState = NULL;
     }
 }

 void QLua::pushFunction(QString funcName, lua_CFunction func)
 {
     if (funcName.isEmpty()) return;
     if (func == NULL)       return;

     lua_pushcfunction(luaState, func);
     lua_setglobal(luaState, funcName.toLocal8Bit().data());
 }

 void QLua::beginModule(QString name)
 {
     if(luaState == NULL) return;

     if (isStartModule == false)
     {
         tolua_open(luaState);
         tolua_module(luaState, NULL, );
         isStartModule = true;
     }

     const char *str = name.isEmpty()? NULL : name.toLocal8Bit().data();
     tolua_beginmodule(luaState, str);
 }

 void QLua::addType(QString name, lua_CFunction deleteFunc)
 {
     if (luaState == NULL) return;
     if (name.isEmpty())   return;
     if (deleteFunc == NULL) return;

     tolua_usertype(luaState, name.toLocal8Bit().data());
     const char *str = name.toLocal8Bit().data();
     tolua_cclass(luaState, str, str, "", deleteFunc);
     beginModule(name);
 }

 void QLua::moduleTypeFunction(QString name, lua_CFunction func)
 {
     if(luaState == NULL) return ;
     if (name.isEmpty())  return;

     const char *str = name.toLocal8Bit().data();
     tolua_function(luaState, str, func);
 }

 void QLua::endModule()
 {
     tolua_endmodule(luaState);
 }

 void QLua::run(QString str)
 {
     luaL_loadbuffer(luaState, str.toLocal8Bit().data(), str.length(), "line");
     lua_pcall(luaState, , , );
 }

QLua类可以方便的实现一些简单的Lua操作，如初始化，关闭，运行Lua代码，绑定函数等。

笔者目前想做到的是能在Lua代码中自有的生成Qt对象，然后能连接Qt原生对象的信号与槽。那么如何实现呢？

Qt中连接信号与槽的函数是QObject::connect(QObject * a, SIGNAL(), QObject * b, SLOT())。首先，我们要弄清楚SIGNAL和SLOT到底是什么。

从connect的参数列表中，我们可以很清晰的看到SIGNAL和SLOT的结果都是char*类型的字符串。我们可以直接在SIGNAL上点右键，转到SIGNAL的定义。或者做个简单的实验。测试如下Qt代码：

    qDebug() << QString::fromLocal8Bit(SIGNAL(clicked()));
    qDebug() << QString::fromLocal8Bit(SLOT(close()));

得到的结果很有意思：

"2clicked()"
"1close()" 

简单总结就是我们只要传入函数名的字符串，加上前缀即可。SIGNAL的前缀是2，SLOT的前缀是1。

这样我们就可以实现在Lua中的connect函数了。仍在使用C++编写，然后绑定到Lua里。如下：

 static int connect(lua_State* state)
 {
     QObject * a = (QObject*)tolua_tousertype(state, , );
     const char * signal = tolua_tostring(state, , );
     QObject * b = (QObject*)tolua_tousertype(state, , );
     const char * slot = tolua_tostring(state, , );

     QObject::connect(a, QString("2%0").arg(signal).toLocal8Bit().data(),
                      b, QString("1%0").arg(slot).toLocal8Bit().data());
 }

绑定时可以使用上面的QLua类：

lua.pushFunction("connect", connect);

完整main.cpp代码如下：

#include "include/lua.hpp"
#include "qlua.h"
#include <QWidget>
#include <QApplication>
#include <QFile>
#include <QDebug>

static int test(lua_State* state)
{
    QPushButton* a = (QPushButton*)tolua_tousertype(state, , );
    if(a)
        a->show();
}

static int connect(lua_State* state)
{
    QObject * a = (QObject*)tolua_tousertype(state, , );
    const char * signal = tolua_tostring(state, , );
    QObject * b = (QObject*)tolua_tousertype(state, , );
    const char * slot = tolua_tostring(state, , );

    QObject::connect(a, QString("2%0").arg(signal).toLocal8Bit().data(),
                     b, QString("1%0").arg(slot).toLocal8Bit().data());
}

static int tolua_new_QWidget(lua_State* state)
{
    QWidget* widget = new QWidget();
    tolua_pushusertype(state, widget, "QWidget");
    return ;
}

static int tolua_delete_QWidget(lua_State* state)
{
    qDebug() << "delete Start";
    QWidget* widget = (QWidget* )tolua_tousertype(state, , );
    if(NULL != widget)
    {
        qDebug() << "delete~";
        widget->close();
        delete widget;
    }
    return ;
}

static int tolua_Show_QWidget(lua_State* state)
{
    QWidget* widget = (QWidget* )tolua_tousertype(state, , );

    if(widget != NULL)
    {
        widget->show();
    }
    return ;
}

static int tolua_new_QPushButton(lua_State* state)
{
    QPushButton* button = new QPushButton();
    tolua_pushusertype(state, button, "QPushButton");
    return ;
}

static int tolua_delete_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, , );
    if(NULL != button)
    {
        button->close();
        delete button;
    }
    return ;
}

static int tolua_Show_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, , );

    if(button != NULL)
    {
        button->show();
    }
    return ;
}

static int tolua_setText_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, , );
    const char * text = tolua_tostring(state, , );

    if(button != NULL)
    {
        button->setText(QString::fromLocal8Bit(text));
    }
    return ;
}

static int tolua_Resize_QWidget(lua_State* state)
{
    QWidget* widget = (QWidget* )tolua_tousertype(state, , );
    double a = tolua_tonumber(state, , );
    double b = tolua_tonumber(state, , );

    if(widget)
    {
        widget->resize((int)a, (int)b);
    }
    return ;
}

static int QApplication_instance(lua_State* state)
{
    tolua_pushusertype(state, QApplication::instance(), "QApplication");
    return ;
}

static int QApplication_quit(lua_State* state)
{
    QApplication * app = (QApplication *)tolua_tousertype(state, , );
    if(app)
        app->quit();
    return ;
}

static int QApplication_delete(lua_State*)
{
    return ;
}

int main(int argc, char * argv[])
{
    Q_INIT_RESOURCE(resources);
    QApplication a(argc, argv);

    QLua lua;

    lua.beginModule("");

    lua.addType("QWidget", tolua_delete_QWidget);
    lua.moduleTypeFunction("new", tolua_new_QWidget);
    lua.moduleTypeFunction("show", tolua_Show_QWidget);
    lua.moduleTypeFunction("resize", tolua_Resize_QWidget);
    lua.endModule();

    lua.addType("QPushButton", tolua_delete_QPushButton);
    lua.moduleTypeFunction("new", tolua_new_QPushButton);
    lua.moduleTypeFunction("show", tolua_Show_QPushButton);
    lua.moduleTypeFunction("setText", tolua_setText_QPushButton);
    lua.endModule();

    lua.addType("QApplication", QApplication_delete);
    lua.moduleTypeFunction("instance", QApplication_instance);
    lua.moduleTypeFunction("quit", QApplication_quit);
    lua.endModule();

    lua.endModule();

    lua.pushFunction("test", test);
    lua.pushFunction("connect", connect);

    // 读取资源文件
    QFile file("://test.lua");
    file.open(QIODevice::ReadOnly | QIODevice::Text);

    QTextStream in(&file);
    in.setCodec("UTF-8");

    // 执行
    lua.run(in.readAll());

    return a.exec();
}

test.lua代码如下：

widget = QWidget:new()
widget:show()

button = QPushButton:new()
button:setText("China")
button:show()

connect(button, "clicked()", widget, "close()")
connect(button, "clicked()", button, "close()")

print("run over")

程序运行结果如下：

点击China按钮，button和widget的窗口都会关闭。

至此，已经实现了连接 Qt 对象的信号与槽。

如果继续做下去，完全可以实现在Lua脚本中使用Qt的类和对象，写出Lua的Gui程序。

附完整代码工程文件：http://pan.baidu.com/s/1ntmFdjj

附个偶的博客地址：http://www.cnblogs.com/IT-BOY/