重构了连接数据库、设置设备名的代码，封装为类

CardManageSystem.pro

@@ -14,6 +14,8 @@ SOURCES += \
 
 HEADERS += \
     HF15693.h \
+    databaseAPI.h \
+    deviceAPI.h \
     mainwindow.h \
     newCardPage.h \
     quitAppPage.h \

databaseAPI.h

@@ -0,0 +1,83 @@
+#ifndef DATABASEAPI_H
+#define DATABASEAPI_H
+
+
+#include <QSqlDatabase>
+#include <QString>
+
+
+class Database
+{
+private:
+    QSqlDatabase db;
+    bool connected = false;
+    QString databaseName = QString("cardManageSystem");
+    QString userName = QString("cardManageSystem");
+
+public:
+    Database(QSqlDatabase database)
+    {
+        db = database;
+        db.setDatabaseName(databaseName);
+        db.setUserName(userName);
+    }
+
+    Database(QSqlDatabase database, QString hostName, int port, QString password)
+    {
+        db = database;
+        db.setDatabaseName(databaseName);
+        db.setUserName(userName);
+        db.setHostName(hostName);
+        db.setPort(port);
+        db.setPassword(password);
+    }
+
+    QSqlDatabase getDatabase()
+    {
+        return db;
+    }
+
+    void setHostName(QString hostName)
+    {
+        db.setHostName(hostName);
+    }
+
+    QString getHostName()
+    {
+        return db.hostName();
+    }
+
+    void setPort(int port)
+    {
+        db.setPort(port);
+    }
+
+    int getPort()
+    {
+        return db.port();
+    }
+
+    void setPassword(QString password)
+    {
+        db.setPassword(password);
+    }
+
+    bool is_connected()
+    {
+        return connected;
+    }
+
+    bool open()
+    {
+        connected = db.open();
+        return connected;
+    }
+
+    ~Database()
+    {
+        db.close();
+    }
+};
+
+
+#endif // DATABASEAPI_H

deviceAPI.h

@@ -0,0 +1,51 @@
+#ifndef DEVICEAPI_H
+#define DEVICEAPI_H
+
+#include <QString>
+#include <QSqlQuery>
+#include <databaseAPI.h>
+
+class Device
+{
+private:
+    bool connected = false;
+    bool depositAllowed = false;
+    QString name = QString("未指定设备名");
+
+public:
+    bool is_connected()
+    {
+        return connected;
+    }
+
+    bool is_depositAllowed()
+    {
+        return depositAllowed;
+    }
+
+    void setDevice(QString name, Database *db)
+    {
+        QSqlQuery query(db->getDatabase());
+        QString sql = QString("select * from device where `name` = '%1';").arg(name);
+        query.exec(sql);
+        if (query.next())
+        {
+            connected = true;
+            this->name = name;
+            depositAllowed = query.value(2).toBool();
+        }
+        else
+        {
+            connected = false;
+            depositAllowed = false;
+        }
+    }
+
+    QString getName()
+    {
+        if (connected) return name;
+        else return QString("未指定设备名");
+    }
+};
+
+#endif // DEVICEAPI_H

mainwindow.cpp

@@ -33,7 +33,7 @@ MainWindow::MainWindow(QWidget *parent)
     databaseLabel = new QLabel("数据库无连接");
     ui->statusBar->addWidget(databaseLabel);
 
-    deviceLabel = new QLabel(device);
+    deviceLabel = new QLabel(device.getName());
     ui->statusBar->addWidget(deviceLabel);
 
     ui->stackedWidget->setCurrentWidget(ui->settingPage);

mainwindow.h

@@ -6,10 +6,11 @@
 #include <QLabel>
 #include <QStackedWidget>
 #include <QMessageBox>
-#include <QSqlDatabase>
 #include <QSqlQuery>
 
 #include <readerAPI.h>
+#include <databaseAPI.h>
+#include <deviceAPI.h>
 
 QT_BEGIN_NAMESPACE
 namespace Ui {
@@ -43,12 +44,8 @@ private slots:
 private:
     Ui::MainWindow *ui;
     Reader reader;
-    QSqlDatabase db;
-    QString databaseIpAddr = "";
-    int databasePort = 3306;
-    QString databasePassword = "";
-    QString device = QString("未指定设备名");
-    bool depositAllowed = false;
+    Database *db = nullptr;
+    Device device;
 
     QStatusBar *statusBar;
     QStackedWidget *stackedWidget;

settingPage.h

@@ -63,43 +63,38 @@ void MainWindow::on_connectReaderButton_clicked()
 */
 void MainWindow::on_connectDatabaseButton_clicked()
 {
-    databaseIpAddr = ui->ipAddrEdit->text();
-    databasePort = ui->portBox->value();
-    databasePassword = ui->passwordEdit->text();
+    if (db == nullptr)
+    {
+        db = new Database(QSqlDatabase::addDatabase("QMYSQL"), ui->ipAddrEdit->text(), ui->portBox->value(), ui->passwordEdit->text());
+    }
+    else
+    {
+        db->setHostName(ui->ipAddrEdit->text());
+        db->setPort(ui->portBox->value());
+        db->setPassword(ui->passwordEdit->text());
+    }
 
-    db = QSqlDatabase::addDatabase("QMYSQL");
-    db.setHostName(databaseIpAddr);
-    db.setPort(databasePort);
-    db.setPassword(databasePassword);
-    db.setDatabaseName("cardManageSystem");
-    db.setUserName("cardManageSystem");
-
-    if (!db.open())
+    if (!db->open())
     {
         QMessageBox::warning(this, QString("数据库状态提示"), QString("数据库连接失败，请重试。"));
         databaseConnectStatusCheckBox->setChecked(false);
         databaseLabel->setText(QString("数据库未连接"));
-        databaseIpAddr = "";
         return;
     }
     databaseConnectStatusCheckBox->setChecked(true);
-    databaseLabel->setText(QString("数据库已连接：") + databaseIpAddr + QString(":") + QString::number(databasePort));
+    databaseLabel->setText(QString("数据库已连接：") + db->getHostName() + QString(":") + QString::number(db->getPort()));
 
-    device = ui->deviceEdit->text();
-    QSqlQuery query;
-    QString sql = QString("select * from device where id = '%1';").arg(device);
-    query.exec(sql);
-    if (query.next())
+    device.setDevice(ui->deviceEdit->text(), db);
+    if (!device.is_connected())
     {
-        if (query.value(2).toBool()) depositAllowed = true;
-        else depositAllowed = false;
+        QMessageBox::warning(this, QString("设备名提示"), QString("该设备名无效，请重试。"));
+        deviceLabel->setText(device.getName());
     }
     else
     {
-        device = QString("未指定设备名");
-        QMessageBox::warning(this, QString("设备名提示"), QString("该设备名无效，请重试。"));
+        if (device.is_depositAllowed()) deviceLabel->setText(device.getName() + QString("（可充值）"));
+        else deviceLabel->setText(device.getName() + QString("（仅可消费）"));
     }
-    deviceLabel->setText(device);
 }
 
 
@@ -110,7 +105,9 @@ void MainWindow::on_connectDatabaseButton_clicked()
 */
 bool MainWindow::ready()
 {
-    if (!reader.is_connected() || databaseIpAddr.isEmpty()) return false;
+    if (!reader.is_connected()) return false;
+    if (db == nullptr || !db->is_connected()) return false;
+    if (!device.is_connected()) return false;
     return true;
 }