add: persist last successful connection config and show connection errors

auth.cpp

@@ -1,20 +1,35 @@
 #include "auth.h"
 
+#include <QMessageBox>
+#include <QSettings>
+#include <QSqlError>
+
 auth::auth(QWidget *parent)
-    : QWidget{ parent }, _nicknameLabel (new QLabel ("nickname:")),
-      _nicknameEdit (new QLineEdit ()),
-      _passwordLabel (new QLabel ("passwprd:")),
-      _passwordEdit (new QLineEdit ()),
-      _addressLabel (new QLabel ("address:")), _addressEdit (new QLineEdit ()),
-      _portLabel (new QLabel ("port:")), _portEdit (new QLineEdit ()),
-      _okButton (new QPushButton ("&OK")),
-      _quitButton (new QPushButton ("&QUIT")), _vbox (new QVBoxLayout (parent))
+    : QWidget{parent}
+    , _nicknameLabel(new QLabel("nickname:"))
+    , _nicknameEdit(new QLineEdit())
+    , _passwordLabel(new QLabel("passwprd:"))
+    , _passwordEdit(new QLineEdit())
+    , _addressLabel(new QLabel("address:"))
+    , _addressEdit(new QLineEdit())
+    , _portLabel(new QLabel("port:"))
+    , _portEdit(new QLineEdit())
+    , _okButton(new QPushButton("&OK"))
+    , _quitButton(new QPushButton("&QUIT"))
+    , _vbox(new QVBoxLayout(this))
+    , _db(QSqlDatabase::addDatabase("QPSQL"))
 {
   _nicknameLabel->setAlignment (Qt::AlignHCenter);
   _passwordLabel->setAlignment (Qt::AlignHCenter);
   _addressLabel->setAlignment (Qt::AlignHCenter);
   _portLabel->setAlignment (Qt::AlignHCenter);
   _passwordEdit->setEchoMode (QLineEdit::Password);
+
+  QSettings settings ("mysitenews", "mysitenews");
+  _nicknameEdit->setText (settings.value ("db/user").toString ());
+  _passwordEdit->setText (settings.value ("db/password").toString ());
+  _addressEdit->setText (settings.value ("db/host").toString ());
+  _portEdit->setText (settings.value ("db/port", "5432").toString ());
   _vbox->addWidget (_nicknameLabel);
   _vbox->addWidget (_nicknameEdit);
   _vbox->addWidget (_passwordLabel);
@@ -33,16 +48,24 @@ auth::auth (QWidget *parent)
 void
 auth::onAuth ()
 {
-    QSqlDatabase *db = new QSqlDatabase(QSqlDatabase::addDatabase("QPSQL"));
-    db->setHostName(_addressEdit->text());
-    db->setPort(_portEdit->text().toInt());
-    db->setDatabaseName("cards");
-    db->setUserName(_nicknameEdit->text());
-    db->setPassword(_passwordEdit->text());
-    bool ok = db->open();
-    if (ok) {
-        emit dbOpenned(db);
+    QSettings settings ("mysitenews", "mysitenews");
+    _db.setHostName(_addressEdit->text());
+    _db.setPort(_portEdit->text().toInt());
+    _db.setDatabaseName(settings.value ("db/database", "cards").toString ());
+    _db.setUserName(_nicknameEdit->text());
+    _db.setPassword(_passwordEdit->text());
+    if (!_db.open()) {
+        QMessageBox::critical(this, tr("Ошибка подключения"),
+                              _db.lastError().text());
+        return;
     }
 
+    settings.setValue ("db/host", _db.hostName ());
+    settings.setValue ("db/port", _db.port ());
+    settings.setValue ("db/database", _db.databaseName ());
+    settings.setValue ("db/user", _db.userName ());
+    settings.setValue ("db/password", _db.password ());
+
+    emit dbOpenned(_db);
     close();
 }

auth.h

@@ -26,10 +26,11 @@ private:
   QPushButton *_okButton = nullptr;
   QPushButton *_quitButton = nullptr;
   QVBoxLayout *_vbox = nullptr;
+  QSqlDatabase _db;
   public slots:
   void onAuth ();
 signals:
-    void dbOpenned(QSqlDatabase *);
+    void dbOpenned(const QSqlDatabase &);
 };
 
 #endif // AUTH_H