Qt图形界面编程入门（标签与槽机制习题分享）

我就是我 2022-11-15 11:30 173阅读 0赞

标签对象初始显示0，每次单击标签对象后，其显示内容就加1，依次变为1、2、3等。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70][]

#ifndef DIALOG_H
    #define DIALOG_H
    
    #include <QDialog>
    #include <QPushButton>      //包含命令按钮类
    #include "MyLabel.h"
    
    class Dialog : public QDialog
    {
        Q_OBJECT
    
    public:
        Dialog(QWidget *parent = 0);
        ~Dialog();
    
    private:
        MyLabel* label;  //定义标签
        QPushButton* btn;   //定义命令按钮
    };
    
    #endif // DIALOG_H

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 1][]

#ifndef MYLABEL_H
    #define MYLABEL_H
    
    #include <QLabel>
    #include <QString>
    
    class MyLabel:public QLabel
    {
        Q_OBJECT          //使用信号槽机制的类必须在头文件中嵌入宏Q_OBJECT，且该类必须为QObject派生类
    
    public:
        //构造函数
        MyLabel(const QString &text, QWidget *parent=0):QLabel(text,parent){}
        //析构函数
        ~MyLabel(){}
    public slots:
        void AddNum()
        {
            QString str = this->text();
            QString str_num = str.mid(12);
            int num = str_num.toInt();
            ++num;
            QString str_new = str.left(12) + QString::number(num);
            this->setText(str_new);
            this->adjustSize();//自适应调整标签的大小
        }
    
    };
    
    
    #endif // MYLABEL_H

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 2][]

#include "dialog.h"
    
    Dialog::Dialog(QWidget *parent)
        : QDialog(parent)
    {
        resize(300,300);
        label = new MyLabel("click nest: 0",this);//动态创建标签对象,设置文本
        btn = new QPushButton("请点击我",this); //动态创建标签对象,设置文本
        label->move(125,150);//移动到指定位置
        btn->move(125,110);
        //连接信号函数和槽函数
        //当单击clicked()命令按钮时发送信号
        //开始执行槽函数
        connect(btn,SIGNAL(clicked()),label,SLOT(AddNum()));//连接信号和槽，信号函数与槽函数的参数列表必须完全相同
    }
    
    Dialog::~Dialog()
    {
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 3][]

#include "dialog.h"
    #include <QApplication>
    
    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv);
        Dialog w;
        w.show();
    
        return a.exec();
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 4][]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20210331172646213.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA==,size_16,color_FFFFFF,t_70
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/2021033117283464.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTYyNjQ2OA==,size_16,color_FFFFFF,t_70