槽函数声明

private slots:void on_ed_textChanged();void on_pushButton_clicked();
};

槽函数定义

void Widget::on_ed_textChanged()//文本框
{if(ui->ed1->text().length()>=5&&ui->ed2->text().length()>=5){ui->pushButton->setStyleSheet("background-color:green");}elseui->pushButton->setStyleSheet("background-color:red");
}void Widget::on_pushButton_clicked()//按钮
{if(ui->ed1->text()=="Admin"&&ui->ed2->text()=="12345")qDebug("登录成功");else{qDebug("账号或密码错误，请重新输入");ui->ed1->clear();ui->ed2->clear();}
}

信号与槽连接

    QObject::connect(ui->ed1,&QLineEdit::textChanged,this,&Widget::on_ed_textChanged);QObject::connect(ui->ed2,&QLineEdit::textChanged,this,&Widget::on_ed_textChanged);QObject::connect(ui->pushButton,&QPushButton::clicked,this,&Widget::on_pushButton_clicked);