BtChat example: improve code

Improve the example code according to guidelines:
* fix CMakeLists.txt by using qt_standard_project_setup() and PRIVATE
  linking
* fix memory leak in Chat dialog
* fix includes
* fix forward declarations and do not use QT_USE_NAMESPACE
* use Qt::StringLiterals
* remove outdated warning for Windows platform
* split too long lines

Task-number: QTBUG-111972
Pick-to: 6.5 6.5.0
Change-Id: I81e472cfacf8c6adf97b31e97254797d40b01519
Reviewed-by: Juha Vuolle <juha.vuolle@qt.io>

10 files changed, 54 insertions, 47 deletions

diff --git a/examples/bluetooth/btchat/CMakeLists.txt b/examples/bluetooth/btchat/CMakeLists.txt
index dc7ac2a0..ef578b88 100644
--- a/examples/bluetooth/btchat/CMakeLists.txt
+++ b/examples/bluetooth/btchat/CMakeLists.txt
@@ -1,12 +1,9 @@
-# Copyright (C) 2022 The Qt Company Ltd.
+# Copyright (C) 2023 The Qt Company Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 
 cmake_minimum_required(VERSION 3.16)
 project(btchat LANGUAGES CXX)
 
-set(CMAKE_AUTOMOC ON)
-set(CMAKE_AUTOUIC ON)
-
 if(NOT DEFINED INSTALL_EXAMPLESDIR)
     set(INSTALL_EXAMPLESDIR "examples")
 endif()
@@ -15,6 +12,8 @@ set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/bluetooth/btchat")
 
 find_package(Qt6 REQUIRED COMPONENTS Bluetooth Core Widgets)
 
+qt_standard_project_setup()
+
 qt_add_executable(btchat
     chat.cpp chat.h chat.ui
     chatclient.cpp chatclient.h
@@ -28,7 +27,7 @@ set_target_properties(btchat PROPERTIES
     MACOSX_BUNDLE TRUE
 )
 
-target_link_libraries(btchat PUBLIC
+target_link_libraries(btchat PRIVATE
     Qt::Bluetooth
     Qt::Core
     Qt::Widgets
diff --git a/examples/bluetooth/btchat/chat.cpp b/examples/bluetooth/btchat/chat.cpp
index d8cea5b8..cdaa28d8 100644
--- a/examples/bluetooth/btchat/chat.cpp
+++ b/examples/bluetooth/btchat/chat.cpp
@@ -2,24 +2,26 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
 #include "chat.h"
-#include "remoteselector.h"
-#include "chatserver.h"
 #include "chatclient.h"
+#include "chatserver.h"
+#include "remoteselector.h"
+#include "ui_chat.h"
 
-#include <QCoreApplication>
 #include <QtCore/qdebug.h>
 
 #include <QtBluetooth/qbluetoothdeviceinfo.h>
 #include <QtBluetooth/qbluetoothlocaldevice.h>
 #include <QtBluetooth/qbluetoothuuid.h>
 
-static const QLatin1String serviceUuid("e8e10f95-1a70-4b27-9ccf-02010264e9c8");
+using namespace Qt::StringLiterals;
+
+static constexpr auto serviceUuid = "e8e10f95-1a70-4b27-9ccf-02010264e9c8"_L1;
 #ifdef Q_OS_ANDROID
-static const QLatin1String reverseUuid("c8e96402-0102-cf9c-274b-701a950fe1e8");
+static constexpr auto reverseUuid = "c8e96402-0102-cf9c-274b-701a950fe1e8"_L1;
 #endif
 
 Chat::Chat(QWidget *parent)
-    : QDialog(parent), ui(new Ui_Chat)
+    : QDialog(parent), ui(new Ui::Chat)
 {
     //! [Construct UI]
     ui->setupUi(this);
@@ -28,6 +30,7 @@ Chat::Chat(QWidget *parent)
     connect(ui->connectButton, &QPushButton::clicked, this, &Chat::connectClicked);
     connect(ui->sendButton, &QPushButton::clicked, this, &Chat::sendClicked);
     //! [Construct UI]
+    ui->connectButton->setFocus();
 
     localAdapters = QBluetoothLocalDevice::allDevices();
     if (localAdapters.size() < 2) {
@@ -49,12 +52,6 @@ Chat::Chat(QWidget *parent)
         adapter.setHostMode(QBluetoothLocalDevice::HostDiscoverable);
     } else {
         qWarning("Local adapter is not found! The application might work incorrectly.");
-#ifdef Q_OS_WIN
-        // WinRT implementation does not support adapter information yet. So it
-        // will always return an empty list.
-        qWarning("If the adapter exists, make sure to pair the devices manually before launching"
-                 " the chat.");
-#endif
     }
 
     //! [Create Chat Server]
@@ -78,6 +75,7 @@ Chat::~Chat()
 {
     qDeleteAll(clients);
     delete server;
+    delete ui;
 }
 
 //! [clientConnected clientDisconnected]
@@ -162,13 +160,11 @@ void Chat::connectClicked()
     if (remoteSelector.exec() == QDialog::Accepted) {
         QBluetoothServiceInfo service = remoteSelector.service();
 
-        qDebug() << "Connecting to service 2" << service.serviceName()
+        qDebug() << "Connecting to service" << service.serviceName()
                  << "on" << service.device().name();
 
         // Create client
-        qDebug() << "Going to create client";
         ChatClient *client = new ChatClient(this);
-qDebug() << "Connecting...";
 
         connect(client, &ChatClient::messageReceived,
                 this, &Chat::showMessage);
@@ -179,7 +175,6 @@ qDebug() << "Connecting...";
         connect(client, &ChatClient::socketErrorOccurred,
                 this, &Chat::reactOnSocketError);
         connect(this, &Chat::sendMessage, client, &ChatClient::sendMessage);
-qDebug() << "Start client";
         client->startClient(service);
 
         clients.append(client);
@@ -202,7 +197,12 @@ void Chat::sendClicked()
 
     ui->sendText->setEnabled(true);
     ui->sendButton->setEnabled(true);
+#if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
+    // avoid keyboard automatically popping up again on mobile devices
+    ui->sendButton->setFocus();
+#else
     ui->sendText->setFocus();
+#endif
 }
 //! [sendClicked]
 
diff --git a/examples/bluetooth/btchat/chat.h b/examples/bluetooth/btchat/chat.h
index 846e91dd..a9e99395 100644
--- a/examples/bluetooth/btchat/chat.h
+++ b/examples/bluetooth/btchat/chat.h
@@ -1,13 +1,15 @@
 // Copyright (C) 2017 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
-#include "ui_chat.h"
-
 #include <QtWidgets/qdialog.h>
 
 #include <QtBluetooth/qbluetoothhostinfo.h>
 
-QT_USE_NAMESPACE
+QT_BEGIN_NAMESPACE
+namespace Ui {
+    class Chat;
+}
+QT_END_NAMESPACE
 
 class ChatServer;
 class ChatClient;
@@ -41,7 +43,7 @@ private slots:
 private:
     int adapterFromUserSelection() const;
     int currentAdapterIndex = 0;
-    Ui_Chat *ui;
+    Ui::Chat *ui;
 
     ChatServer *server;
     QList<ChatClient *> clients;
diff --git a/examples/bluetooth/btchat/chatclient.cpp b/examples/bluetooth/btchat/chatclient.cpp
index c7bb3795..f69fc455 100644
--- a/examples/bluetooth/btchat/chatclient.cpp
+++ b/examples/bluetooth/btchat/chatclient.cpp
@@ -5,6 +5,10 @@
 
 #include <QtCore/qmetaobject.h>
 
+#include <QtBluetooth/qbluetoothserviceinfo.h>
+
+using namespace  Qt::StringLiterals;
+
 ChatClient::ChatClient(QObject *parent)
     :   QObject(parent)
 {
@@ -70,8 +74,8 @@ void ChatClient::onSocketErrorOccurred(QBluetoothSocket::SocketError error)
         return;
 
     QMetaEnum metaEnum = QMetaEnum::fromType<QBluetoothSocket::SocketError>();
-    QString errorString = socket->peerName() + QLatin1Char(' ')
-            + metaEnum.valueToKey(static_cast<int>(error)) + QLatin1String(" occurred");
+    QString errorString = socket->peerName() + ' '_L1
+            + metaEnum.valueToKey(static_cast<int>(error)) + " occurred"_L1;
 
     emit socketErrorOccurred(errorString);
 }
diff --git a/examples/bluetooth/btchat/chatclient.h b/examples/bluetooth/btchat/chatclient.h
index 89c4813f..829562ac 100644
--- a/examples/bluetooth/btchat/chatclient.h
+++ b/examples/bluetooth/btchat/chatclient.h
@@ -6,12 +6,9 @@
 
 #include <QtCore/qobject.h>
 
-#include <QtBluetooth/qbluetoothserviceinfo.h>
 #include <QtBluetooth/qbluetoothsocket.h>
 
-QT_FORWARD_DECLARE_CLASS(QBluetoothSocket)
-
-QT_USE_NAMESPACE
+QT_FORWARD_DECLARE_CLASS(QBluetoothServiceInfo)
 
 //! [declaration]
 class ChatClient : public QObject
diff --git a/examples/bluetooth/btchat/chatserver.cpp b/examples/bluetooth/btchat/chatserver.cpp
index 2e6c314d..7a6ef80d 100644
--- a/examples/bluetooth/btchat/chatserver.cpp
+++ b/examples/bluetooth/btchat/chatserver.cpp
@@ -6,8 +6,10 @@
 #include <QtBluetooth/qbluetoothserver.h>
 #include <QtBluetooth/qbluetoothsocket.h>
 
+using namespace Qt::StringLiterals;
+
 //! [Service UUID]
-static const QLatin1String serviceUuid("e8e10f95-1a70-4b27-9ccf-02010264e9c8");
+static constexpr auto serviceUuid = "e8e10f95-1a70-4b27-9ccf-02010264e9c8"_L1;
 //! [Service UUID]
 
 ChatServer::ChatServer(QObject *parent)
@@ -64,10 +66,10 @@ void ChatServer::startServer(const QBluetoothAddress& localAdapter)
     //! [Service UUID set]
 
     //! [Service Discoverability]
+    const auto groupUuid = QBluetoothUuid(QBluetoothUuid::ServiceClassUuid::PublicBrowseGroup);
     QBluetoothServiceInfo::Sequence publicBrowse;
-    publicBrowse << QVariant::fromValue(QBluetoothUuid(QBluetoothUuid::ServiceClassUuid::PublicBrowseGroup));
-    serviceInfo.setAttribute(QBluetoothServiceInfo::BrowseGroupList,
-                             publicBrowse);
+    publicBrowse << QVariant::fromValue(groupUuid);
+    serviceInfo.setAttribute(QBluetoothServiceInfo::BrowseGroupList, publicBrowse);
     //! [Service Discoverability]
 
     //! [Protocol descriptor list]
@@ -122,7 +124,8 @@ void ChatServer::clientConnected()
         return;
 
     connect(socket, &QBluetoothSocket::readyRead, this, &ChatServer::readSocket);
-    connect(socket, &QBluetoothSocket::disconnected, this, QOverload<>::of(&ChatServer::clientDisconnected));
+    connect(socket, &QBluetoothSocket::disconnected,
+            this, QOverload<>::of(&ChatServer::clientDisconnected));
     clientSockets.append(socket);
     clientNames[socket] = socket->peerName();
     emit clientConnected(socket->peerName());
diff --git a/examples/bluetooth/btchat/chatserver.h b/examples/bluetooth/btchat/chatserver.h
index b7c60ef7..a8811f77 100644
--- a/examples/bluetooth/btchat/chatserver.h
+++ b/examples/bluetooth/btchat/chatserver.h
@@ -12,8 +12,6 @@
 QT_FORWARD_DECLARE_CLASS(QBluetoothServer)
 QT_FORWARD_DECLARE_CLASS(QBluetoothSocket)
 
-QT_USE_NAMESPACE
-
 //! [declaration]
 class ChatServer : public QObject
 {
diff --git a/examples/bluetooth/btchat/main.cpp b/examples/bluetooth/btchat/main.cpp
index 1af468f0..6347c914 100644
--- a/examples/bluetooth/btchat/main.cpp
+++ b/examples/bluetooth/btchat/main.cpp
@@ -3,8 +3,8 @@
 
 #include "chat.h"
 
+#include <QtCore/qloggingcategory.h>
 #include <QtWidgets/qapplication.h>
-#include <QtCore/QLoggingCategory>
 
 int main(int argc, char *argv[])
 {
@@ -14,7 +14,7 @@ int main(int argc, char *argv[])
     Chat d;
     QObject::connect(&d, &Chat::accepted, &app, &QApplication::quit);
 
-#ifdef Q_OS_ANDROID
+#if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
     d.showMaximized();
 #else
     d.show();
diff --git a/examples/bluetooth/btchat/remoteselector.cpp b/examples/bluetooth/btchat/remoteselector.cpp
index a0a8430c..a7a9a00e 100644
--- a/examples/bluetooth/btchat/remoteselector.cpp
+++ b/examples/bluetooth/btchat/remoteselector.cpp
@@ -4,15 +4,20 @@
 #include "remoteselector.h"
 #include "ui_remoteselector.h"
 
+#include <QtBluetooth/qbluetoothaddress.h>
 #include <QtBluetooth/qbluetoothlocaldevice.h>
 #include <QtBluetooth/qbluetoothservicediscoveryagent.h>
+#include <QtBluetooth/qbluetoothuuid.h>
 
-QT_USE_NAMESPACE
+#include <QtWidgets/qlistwidget.h>
 
 RemoteSelector::RemoteSelector(const QBluetoothAddress &localAdapter, QWidget *parent)
     :   QDialog(parent), ui(new Ui::RemoteSelector)
 {
     ui->setupUi(this);
+#if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
+    setWindowState(Qt::WindowMaximized);
+#endif
 
     m_discoveryAgent = new QBluetoothServiceDiscoveryAgent(localAdapter);
 
diff --git a/examples/bluetooth/btchat/remoteselector.h b/examples/bluetooth/btchat/remoteselector.h
index 5aa3427d..e319caa6 100644
--- a/examples/bluetooth/btchat/remoteselector.h
+++ b/examples/bluetooth/btchat/remoteselector.h
@@ -6,16 +6,15 @@
 
 #include <QtWidgets/qdialog.h>
 
-#include <QtBluetooth/qbluetoothaddress.h>
 #include <QtBluetooth/qbluetoothserviceinfo.h>
-#include <QtBluetooth/qbluetoothuuid.h>
 
-QT_FORWARD_DECLARE_CLASS(QBluetoothServiceDiscoveryAgent)
-QT_FORWARD_DECLARE_CLASS(QListWidgetItem)
+QT_BEGIN_NAMESPACE
 
-QT_USE_NAMESPACE
+class QBluetoothAddress;
+class QBluetoothServiceDiscoveryAgent;
+class QBluetoothUuid;
+class QListWidgetItem;
 
-QT_BEGIN_NAMESPACE
 namespace Ui {
     class RemoteSelector;
 }