DAY2,Qt（继续完善登录框，信号与槽的使用）

1.继续完善登录框，当登录成功时，关闭登录界面，跳转到新的界面中，来回切换页面；

---mychat.h chatroom.h---两个页面头文件

#ifndef MYCHAT_H
#define MYCHAT_H#include <QWidget>
#include <QDebug>  //打印信息
#include <QIcon> //图标
#include <QPushButton>  //按钮
#include <QLineEdit> //行编辑器类
#include <QLabel>  //标签类class Mychat : public QWidget
{Q_OBJECTpublic:Mychat(QWidget *parent = nullptr);~Mychat();QLabel *lab1;  //标签类，设置背景QLabel *lab2;  //设置账号图标QLabel *lab3;  //设置密码图标QLineEdit *edit1;  //行编辑器类，设置明文账号QLineEdit *edit2;  //设置密文密码QPushButton *but1;  //按钮类，设置登录按钮QPushButton *but2;  //设置取消按钮signals:void my_signal();void login_jump();  //登录跳转信号public slots:void login_slot();  //发送跳转信号槽void cancle_slot();void returnjump_slot();  //接收返回信号槽};
#endif // MYCHAT_H

#ifndef CHATROOM_H
#define CHATROOM_H#include <QWidget>namespace Ui {
class Chatroom;
}class Chatroom : public QWidget
{Q_OBJECTpublic:explicit Chatroom(QWidget *parent = nullptr);~Chatroom();signals:void return_jump(); //返回跳转信号public slots:void loginjump_slot();  //接收登录跳转槽private slots:void on_returnjump_clicked();  //发送返回跳转信号槽private:Ui::Chatroom *ui;
};#endif // CHATROOM_H

---mychat.cpp chatroom.cpp---两个页面源文件

#include "mychat.h"Mychat::Mychat(QWidget *parent): QWidget(parent)
{//对组件界面的设置qDebug()<<this->size();this->setFixedSize(this->size());  //固定界面尺寸this->setWindowOpacity(0.9);  //透明度//设置窗口this->setWindowTitle(" 轻松一刻的你");  //窗口内容this->setWindowIcon(QIcon(":/qt_icon/qie.png"));  //窗口图标//设置界面背景,lab1lab1 = new QLabel;lab1->setParent(this);  //将当前组件设置为父组件lab1->resize(700,200);  //更改标签大小lab1->setPixmap(QPixmap(":/qt_icon/background.jpg"));lab1->setScaledContents(true);  //自动适应空间//设置登录页面//账号图标lab2lab2 = new QLabel;lab2->setParent(this);  //将当前组件设置为父组件//lab2->setStyleSheet("background-color:blue;");  //参考lab2->resize(50,40);  //设置大小lab2->move(170,250);  //位置lab2->setPixmap(QPixmap(":/qt_icon/name.png"));lab2->setScaledContents(true);  //自动适应空间//密码图标lab3lab3 = new QLabel(this);//lab3->setStyleSheet("background-color:blue;");  //参考lab3->resize(lab2->size());  //设置大小lab3->move(170,320);  //位置lab3->setPixmap(QPixmap(":/qt_icon/pwd.png"));lab3->setScaledContents(true);  //自动适应空间//行文本设置//输入账号,edit1edit1 = new QLineEdit(this);edit1->move(260,250);  //位置qDebug()<<edit1->size();  //获取大小edit1->resize(220,40);  //设置大小edit1->setPlaceholderText("账号");  //占位提示//输入密码,edit2edit2 = new QLineEdit(this);edit2->move(260,320);  //位置edit2->resize(edit1->size());  //设置大小edit2->setEchoMode(QLineEdit::Password);  //设置密文edit2->setPlaceholderText("密码");  //占位提示//登录按钮but1but1 = new QPushButton(this);qDebug()<<but1->size();  //获取大小//but1->setStyleSheet("background-color:red;");  //参考but1->move(340,400);  //位置but1->resize(70,40);  //设置大小but1->setText("登录");  //文本but1->setIcon(QIcon(":/qt_icon/login.png"));//取消按钮but2but2 = new QPushButton(this);//but2->setStyleSheet("background-color:red;");  //参考but2->move(440,400);  //位置but2->resize(but1->size());  //设置大小but2->setText("取消");  //文本but2->setIcon(QIcon(":/qt_icon/cancle.png"));//取消按钮函数连接my_slot(),qt4// connect(btn3,SIGNAL(clicked()),this,SLOT(my_slot()));  //与自定义槽函数相连connect(but2,SIGNAL(clicked()),this,SLOT(cancle_slot()));//登录按钮函数连接my_slot1(),qt5connect(but1,&QPushButton::clicked,this,&Mychat::login_slot);}Mychat::~Mychat()
{
}//取消按钮槽函数
void Mychat::cancle_slot()
{this->close();
}//登录按钮槽函数
void Mychat::login_slot()
{if(edit1->text() == "admin" && edit2->text() == "123456"){qDebug()<<"登陆成功！";emit login_jump();this->close();}else{qDebug()<<"登陆失败，请重新登录！";edit2->clear();}
}//接收返回信号槽
void Mychat::returnjump_slot()
{this->show();
}

#include "chatroom.h"
#include "ui_chatroom.h"Chatroom::Chatroom(QWidget *parent) :QWidget(parent),ui(new Ui::Chatroom)
{ui->setupUi(this);
}Chatroom::~Chatroom()
{delete ui;
}void Chatroom::loginjump_slot()  //接收登录信号槽
{this->show();
}void Chatroom::on_returnjump_clicked()  //发送疯返回信号槽
{emit return_jump();this->close();
}

---main.cpp---两个页面测试文件

#include "mychat.h"
#include "chatroom.h"#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);Mychat w;w.show();Chatroom c;  //实例化chatroom界面QObject::connect(&w,&Mychat::login_jump,&c,&Chatroom::loginjump_slot);  //连接登录调转信号和槽QObject::connect(&c,&Chatroom::return_jump,&w,&Mychat::returnjump_slot);  //连接返回调转信号和槽return a.exec();
}