请帮我使用MQL4文件编辑器，编写一个ea，添加下多单按钮，下空单按钮，下挂多单按钮，下挂空单按钮，并点击按钮后，可以输入下单的仓位。请帮我写出具体的代码，并注释是每句的含义

好的，我可以为您提供一些MQL4代码来满足您的需求。

首先，我们需要定义一些全局变量来保存按钮的状态和交易方向：

bool buyButtonPressed = false;
bool sellButtonPressed = false;
bool buyLimitButtonPressed = false;
bool sellLimitButtonPressed = false;
int lotSize = 0;

然后，我们可以在初始化函数中创建按钮和设置按钮的坐标和大小：

int init() {
    // 创建按钮
    ObjectCreate("buyButton", OBJ_BUTTON, 0, 0, 0);
    ObjectCreate("sellButton", OBJ_BUTTON, 0, 0, 0);
    ObjectCreate("buyLimitButton", OBJ_BUTTON, 0, 0, 0);
    ObjectCreate("sellLimitButton", OBJ_BUTTON, 0, 0, 0);

    // 设置按钮的坐标和大小
    ObjectSet("buyButton", OBJPROP_XDISTANCE, 10);
    ObjectSet("buyButton", OBJPROP_YDISTANCE, 10);
    ObjectSet("buyButton", OBJPROP_WIDTH, 100);
    ObjectSet("buyButton", OBJPROP_HEIGHT, 30);
    ObjectSet("buyButton", OBJPROP_TEXT, "Buy");

    ObjectSet("sellButton", OBJPROP_XDISTANCE, 120);
    ObjectSet("sellButton", OBJPROP_YDISTANCE, 10);
    ObjectSet("sellButton", OBJPROP_WIDTH, 100);
    ObjectSet("sellButton", OBJPROP_HEIGHT, 30);
    ObjectSet("sellButton", OBJPROP_TEXT, "Sell");

    ObjectSet("buyLimitButton", OBJPROP_XDISTANCE, 230);
    ObjectSet("buyLimitButton", OBJPROP_YDISTANCE, 10);
    ObjectSet("buyLimitButton", OBJPROP_WIDTH, 100);
    ObjectSet("buyLimitButton", OBJPROP_HEIGHT, 30);
    ObjectSet("buyLimitButton", OBJPROP_TEXT, "Buy Limit");

    ObjectSet("sellLimitButton", OBJPROP_XDISTANCE, 340);
    ObjectSet("sellLimitButton", OBJPROP_YDISTANCE, 10);
    ObjectSet("sellLimitButton", OBJPROP_WIDTH, 100);
    ObjectSet("sellLimitButton", OBJPROP_HEIGHT, 30);
    ObjectSet("sellLimitButton", OBJPROP_TEXT, "Sell Limit");

    return(0);
}

接下来，我们需要在OnChartEvent()函数中检测按钮是否被按下，并弹出一个输入框让用户输入下单的仓位：

void OnChartEvent(const int id, const long& lparam, const double& dparam, const string& sparam) {
    if (id == CHARTEVENT_OBJECT_CLICK) { // 检测按钮是否被点击
        if (sparam == "buyButton") { // 多单按钮
            buyButtonPressed = true;
            sellButtonPressed = false;
            buyLimitButtonPressed = false;
            sellLimitButtonPressed = false;
            lotSize = (int)MessageBox("Please enter lot size:", "Buy", MB_OKCANCEL | MB_ICONINFORMATION);
        } else if (sparam == "sellButton") { // 空单按钮
            buyButtonPressed = false;
            sellButtonPressed = true;
            buyLimitButtonPressed = false;
            sellLimitButtonPressed = false;
            lotSize = (int)MessageBox("Please enter lot size:", "Sell", MB_OKCANCEL | MB_ICONINFORMATION);
        } else if (sparam == "buyLimitButton") { // 挂多单按钮
            buyButtonPressed = false;
            sellButtonPressed = false;
            buyLimitButtonPressed = true;
            sellLimitButtonPressed = false;
            lotSize = (int)MessageBox("Please enter lot size:", "Buy Limit", MB_OKCANCEL | MB_ICONINFORMATION);
        } else if (sparam == "sellLimitButton") { // 挂空单按钮
            buyButtonPressed = false;
            sellButtonPressed = false;
            buyLimitButtonPressed = false;
            sellLimitButtonPressed = true;
            lotSize = (int)MessageBox("Please enter lot size:", "Sell Limit", MB_OKCANCEL | MB_ICONINFORMATION);
        }
    }
}

最后，我们可以在OnTick()函数中下单：

void OnTick() {
    if (buyButtonPressed) { // 多单按钮被按下
        OrderSend(Symbol(), OP_BUY, lotSize, Ask, 3, 0, 0, "Buy Order", 0, 0, Green);
        buyButtonPressed = false;
    } else if (sellButtonPressed) { // 空单按钮被按下
        OrderSend(Symbol(), OP_SELL, lotSize, Bid, 3, 0, 0, "Sell Order", 0, 0, Red);
        sellButtonPressed = false;
    } else if (buyLimitButtonPressed) { // 挂多单按钮被按下
        OrderSend(Symbol(), OP_BUYLIMIT, lotSize, Ask - 10 * Point, 3, Ask - 20 * Point, Ask + 20 * Point, "Buy Limit Order", 0, 0, Green);
        buyLimitButtonPressed = false;
    } else if (sellLimitButtonPressed) { // 挂空单按钮被按下
        OrderSend(Symbol(), OP_SELLLIMIT, lotSize, Bid + 10 * Point, 3, Bid + 20 * Point, Bid - 20 * Point, "Sell Limit Order", 0, 0, Red);
        sellLimitButtonPressed = false;
    }
}

以上就是完整的代码，下单时会弹出一个输入框让用户输入下单的仓位，然后根据按钮的状态下单。需要注意的是，这只是一个简单的示例代码，您需要根据您自己的需求进行修改和完善。