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 = 0);
    ~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, 0);
        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, 0, 0, 0);
}

 

    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, 1, 0);
    const char * signal = tolua_tostring(state, 2, 0);
    QObject * b = (QObject*)tolua_tousertype(state, 3, 0);
    const char * slot = tolua_tostring(state, 4, 0);

    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, 1, 0);
    if(a)
        a->show();
}

static int connect(lua_State* state)
{
    QObject * a = (QObject*)tolua_tousertype(state, 1, 0);
    const char * signal = tolua_tostring(state, 2, 0);
    QObject * b = (QObject*)tolua_tousertype(state, 3, 0);
    const char * slot = tolua_tostring(state, 4, 0);

    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 1;
}

static int tolua_delete_QWidget(lua_State* state)
{
    qDebug() << "delete Start";
    QWidget* widget = (QWidget* )tolua_tousertype(state, 1, 0);
    if(NULL != widget)
    {
        qDebug() << "delete~";
        widget->close();
        delete widget;
    }
    return 1;
}

static int tolua_Show_QWidget(lua_State* state)
{
    QWidget* widget = (QWidget* )tolua_tousertype(state, 1, 0);

    if(widget != NULL)
    {
        widget->show();
    }
    return 1;
}

static int tolua_new_QPushButton(lua_State* state)
{
    QPushButton* button = new QPushButton();
    tolua_pushusertype(state, button, "QPushButton");
    return 1;
}

static int tolua_delete_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, 1, 0);
    if(NULL != button)
    {
        button->close();
        delete button;
    }
    return 1;
}

static int tolua_Show_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, 1, 0);

    if(button != NULL)
    {
        button->show();
    }
    return 1;
}

static int tolua_setText_QPushButton(lua_State* state)
{
    QPushButton* button = (QPushButton* )tolua_tousertype(state, 1, 0);
    const char * text = tolua_tostring(state, 2, 0);

    if(button != NULL)
    {
        button->setText(QString::fromLocal8Bit(text));
    }
    return 1;
}

static int tolua_Resize_QWidget(lua_State* state)
{
    QWidget* widget = (QWidget* )tolua_tousertype(state, 1, 0);
    double a = tolua_tonumber(state, 2, 0);
    double b = tolua_tonumber(state, 3, 0);

    if(widget)
    {
        widget->resize((int)a, (int)b);
    }
    return 1;
}

static int QApplication_instance(lua_State* state)
{
    tolua_pushusertype(state, QApplication::instance(), "QApplication");
    return 1;
}

static int QApplication_quit(lua_State* state)
{
    QApplication * app = (QApplication *)tolua_tousertype(state, 1, 0);
    if(app)
        app->quit();
    return 1;
}

static int QApplication_delete(lua_State*)
{
    return 1;
}

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/