【QT】:QT中信号与槽详解

QT中的信号就是某个按钮执行后该之行的函数 
QT中的槽就是一个通用的函数

我们需要把信号和槽关联起来，这样才能实现我们想要的功能。 
总结需要3步： 
1，在widget.h中添加一个函数的声明 
2，在widget.cpp添加函数的具体声明 
3，在widget.cpp添加信号与槽的对应

具体代码：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#ifndef WIDGET_H</span>
<span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#<span class="hljs-keyword" style="margin: 0px; padding: 0px; box-sizing: border-box;">define</span> WIDGET_H</span>

<span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#include <QWidget></span>

namespace Ui {
class Widget;
}

class Widget : <span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">public</span> QWidget
{
    Q_OBJECT

<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:
    <span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">explicit</span> <span class="hljs-title" style="margin: 0px; padding: 0px; box-sizing: border-box;">Widget</span>(QWidget *parent = <span class="hljs-number" style="margin: 0px; padding: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
    ~Widget();
<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">public</span> slots:
     <span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="margin: 0px; padding: 0px; box-sizing: border-box;">FoodIsComing</span>();

<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:
    Ui::Widget *ui;
};

<span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#<span class="hljs-keyword" style="margin: 0px; padding: 0px; box-sizing: border-box;">endif</span> // WIDGET_H</span>
</code><ul class="pre-numbering" style="margin: 0px; padding: 6px 0px 40px; box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">1</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">2</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">3</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">4</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">5</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">6</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">7</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">8</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">9</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">10</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">11</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">12</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">13</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">14</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">15</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">16</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">17</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">18</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">19</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">20</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">21</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">22</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">23</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">24</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">25</li></ul>

cpp

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#include "widget.h"</span>
<span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#include "ui_widget.h"</span>
<span class="hljs-preprocessor" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); box-sizing: border-box;">#include <QMessageBox></span>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Ui::Widget)
{
    ui->setupUi(<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">this</span>);
    connect(ui->pushButton,SIGNAL(clicked()),<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">this</span>,SLOT(FoodIsComing()));
}

Widget::~Widget()
{
    delete ui;
}

<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">void</span> Widget::FoodIsComing(){
    QMessageBox::information(<span class="hljs-keyword" style="margin: 0px; padding: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">this</span>,tr(<span class="hljs-string" style="margin: 0px; padding: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">"送餐"</span>),tr(<span class="hljs-string" style="margin: 0px; padding: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">"叮咚，外卖已经送达"</span>));
}
</code><ul class="pre-numbering" style="margin: 0px; padding: 6px 0px 40px; box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">1</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">2</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">3</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">4</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">5</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">6</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">7</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">8</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">9</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">10</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">11</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">12</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">13</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">14</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">15</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">16</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">17</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">18</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">19</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">20</li><li style="margin: 0px; padding: 0px 5px; box-sizing: border-box;">21</li></ul>

在主界面添加的connect函数 
connect(ui->pushButton,SIGNAL(clicked()),this,SLOT(FoodIsComing()));

注意点： 
使用了什么类，一定要#include 该类 
运行状态： 

上述是手动的代码，下面还有个自动的代码： 
在应用了该按钮之后，进行下一步转到槽操作，然后就可以进行相关函数的写了 
方法： 
1，点击该控件，右键，转到槽，然后选第一个onclick，然后就能进行相关函数的匹配

2，我们发现，通过这个方法，能够省去connect函数，并且代码也大大的简化了，SLOT也都是一对一的关系