QT += core gui \
               sql
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
CONFIG += c++11
# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
    form.cpp \
    main.cpp \
    widget.cpp
HEADERS += \
    config.h \
    form.h \
    widget.h
FORMS += \
    form.ui \
    widget.ui
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

#ifndef CONFIG_H
#define CONFIG_H
#define SQL_BASE "QMYSQL" //用哪种数据库
#define SQL_HOSTNAME "x.x.x.x"  //数据库服务器IP
#define SQL_USERNAME "xxx" //用户名
#define SQL_PASSWORD "xxx" //密码
#define SQL_DATA_1 "xxx" //所要连接的表
#endif // CONFIG_H

#ifndef FORM_H
#define FORM_H
#include <QWidget>
#include <widget.h>
namespace Ui {
class Form;
}
class Form : public QWidget
{
    Q_OBJECT
public:
    explicit Form(QWidget *parent = nullptr);
    ~Form();
private slots:
    void on_pushButton_clicked();
    void on_pushButton_2_clicked();
private:
    Ui::Form *ui;
    bool flag2 = false;
    QString register_ID; // ID Qstring
    QString register_pwd; // password Qstring
    bool flag_len_Password = false;
};
#endif // FORM_H

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <form.h>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
    Q_OBJECT
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private slots:
    void on_pushButton_clicked();
    void on_pushButton_2_clicked();
private:
    Ui::Widget *ui;
    QString ID_get;
    QString Password_get;
    bool flag1 = false;
    bool login_flag = false;
};
#endif // WIDGET_H

#include "form.h"
#include "ui_form.h"
#include <QDebug>
#include <QSqlDatabase>
#include <QMessageBox>
#include <QSqlQuery>
#include <config.h>
Form::Form(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Form)
{
    ui->setupUi(this);
    QSqlDatabase db = QSqlDatabase::addDatabase(SQL_BASE);
        db.setHostName(SQL_HOSTNAME);
        db.setPort(3306);
        db.setDatabaseName(SQL_DATA_1);
        db.setUserName(SQL_USERNAME);
        db.setPassword(SQL_PASSWORD);
        bool ok = db.open();
        if (ok){
            qDebug()<<"sql connect success!";
            flag2 = true;
        }
        else {
            qDebug()<<"error open database！";
        }
}
Form::~Form()
{
    delete ui;
}
void Form::on_pushButton_clicked()
{
    register_ID = ui->lineEdit->text();
    register_pwd = ui->lineEdit_2->text();
    QSqlQuery query;
    query.prepare("insert into test_qt_sql(ID, Password) values(?, ?)");//?占位符
    //给字段设置内容 list
    QVariantList IDlist;
    IDlist<<register_ID;
    QVariantList pwdlist;
    pwdlist<<register_pwd;
    //给字段绑定相应的值,顺序绑定
    query.addBindValue(IDlist);
    query.addBindValue(pwdlist);
    //执行预处理命令
    query.execBatch();
    on_pushButton_2_clicked();
    QMessageBox::information(this, "success", "success！");
}
void Form::on_pushButton_2_clicked()
{
    Widget *widget = new Widget;
    widget->show();
    this->close();
}

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QSqlDatabase>
#include <QMessageBox>
#include <QSqlQuery>
#include <config.h>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    QSqlDatabase db = QSqlDatabase::addDatabase(SQL_BASE);
        db.setHostName(SQL_HOSTNAME);
        db.setPort(3306);
        db.setDatabaseName(SQL_DATA_1);
        db.setUserName(SQL_USERNAME);
        db.setPassword(SQL_PASSWORD);
        bool ok = db.open();
        if (ok){
            qDebug()<<"sql connect success!";
            flag1 = true;
        }
        else {
            qDebug()<<"error open database！";
        }
}
Widget::~Widget()
{
    delete ui;
}
void Widget::on_pushButton_clicked()
{
    ID_get = ui->lineEdit->text(); // 获取lineedit中输入的文本，并存储到Qstring类型变量ID_get中
    Password_get = ui->lineEdit_2->text(); // 获取lineedit_2中输入的文本，并存储到Qstring类型变量Password_get中
    qDebug() << ID_get;
    qDebug() << Password_get;
    if (flag1){ // flag1是一个标记位,用于记录数据库是否连接成功，如果未来凝结成功的话，就不在对连接及逆行判断。
        QSqlQuery query1("select * from test_qt_sql"); // 查询表的内容
        while (query1.next()) {
            QString country = query1.value(0).toString(); // test_qt_sql表第1个字段的内容
            if (country == ID_get){
                qDebug()<<"OK";
                QString country = query1.value(1).toString();//test_qt_sql表第2个字段的内容
                if (country == Password_get){
                    QMessageBox::information(this, "success", "login success!");
                    login_flag = true;
                }
            }
        }
        if (login_flag == false){
            QMessageBox::information(this, "error", "ID or Password error!");
        }
    }
    else{
        QMessageBox::information(this, "error", "Mysql error！");
    }
}
void Widget::on_pushButton_2_clicked()
{
    Form *form = new Form;
    this->close();
    form->show();
}

#include "widget.h"
#include <QApplication>
#include <QPropertyAnimation>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    QPropertyAnimation *animation = new QPropertyAnimation(&w,"windowOpacity");
        animation->setDuration(1000);
        animation->setStartValue(0);
        animation->setEndValue(1);
        animation->start();
    w.show();
    return a.exec();
}