QtNetwork (examples) - update multicastreceiver example

... as soon as we updated multicastsender. Changes are minimal and mostly
cosmetic - use 'explcit' and 'nullptr' where appropriate, make a socket
data-member and not a pointer, move the 'datagram's declaration outside
of a loop.

Task-number: QTBUG-60628
Change-Id: Icfa46e6d2844c40a605f2f4066847594943a8ea8
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

2 files changed, 23 insertions, 27 deletions

diff --git a/examples/network/multicastreceiver/receiver.cpp b/examples/network/multicastreceiver/receiver.cpp
index 10154c60cc..8985ad1d82 100644
--- a/examples/network/multicastreceiver/receiver.cpp
+++ b/examples/network/multicastreceiver/receiver.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
@@ -54,41 +54,39 @@
 #include "receiver.h"
 
 Receiver::Receiver(QWidget *parent)
-    : QDialog(parent)
+    : QDialog(parent),
+      groupAddress(QStringLiteral("239.255.43.21"))
 {
-    groupAddress = QHostAddress("239.255.43.21");
-
     statusLabel = new QLabel(tr("Listening for multicasted messages"));
-    quitButton = new QPushButton(tr("&Quit"));
-
-    udpSocket = new QUdpSocket(this);
-    udpSocket->bind(QHostAddress::AnyIPv4, 45454, QUdpSocket::ShareAddress);
-    udpSocket->joinMulticastGroup(groupAddress);
-
-    connect(udpSocket, SIGNAL(readyRead()),
-            this, SLOT(processPendingDatagrams()));
-    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
+    auto quitButton = new QPushButton(tr("&Quit"));
 
-    QHBoxLayout *buttonLayout = new QHBoxLayout;
+    auto buttonLayout = new QHBoxLayout;
     buttonLayout->addStretch(1);
     buttonLayout->addWidget(quitButton);
     buttonLayout->addStretch(1);
 
-    QVBoxLayout *mainLayout = new QVBoxLayout;
+    auto mainLayout = new QVBoxLayout;
     mainLayout->addWidget(statusLabel);
     mainLayout->addLayout(buttonLayout);
     setLayout(mainLayout);
 
     setWindowTitle(tr("Multicast Receiver"));
+
+    udpSocket.bind(QHostAddress::AnyIPv4, 45454, QUdpSocket::ShareAddress);
+    udpSocket.joinMulticastGroup(groupAddress);
+
+    connect(&udpSocket, SIGNAL(readyRead()),
+            this, SLOT(processPendingDatagrams()));
+    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
 }
 
 void Receiver::processPendingDatagrams()
 {
-    while (udpSocket->hasPendingDatagrams()) {
-        QByteArray datagram;
-        datagram.resize(udpSocket->pendingDatagramSize());
-        udpSocket->readDatagram(datagram.data(), datagram.size());
+    QByteArray datagram;
+    while (udpSocket.hasPendingDatagrams()) {
+        datagram.resize(int(udpSocket.pendingDatagramSize()));
+        udpSocket.readDatagram(datagram.data(), datagram.size());
         statusLabel->setText(tr("Received datagram: \"%1\"")
-                             .arg(datagram.data()));
+                             .arg(datagram.constData()));
     }
 }
diff --git a/examples/network/multicastreceiver/receiver.h b/examples/network/multicastreceiver/receiver.h
index efef1cdb30..54927fdd63 100644
--- a/examples/network/multicastreceiver/receiver.h
+++ b/examples/network/multicastreceiver/receiver.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
@@ -53,11 +53,10 @@
 
 #include <QDialog>
 #include <QHostAddress>
+#include <QUdpSocket>
 
 QT_BEGIN_NAMESPACE
 class QLabel;
-class QPushButton;
-class QUdpSocket;
 QT_END_NAMESPACE
 
 class Receiver : public QDialog
@@ -65,15 +64,14 @@ class Receiver : public QDialog
     Q_OBJECT
 
 public:
-    Receiver(QWidget *parent = 0);
+    explicit Receiver(QWidget *parent = nullptr);
 
 private slots:
     void processPendingDatagrams();
 
 private:
-    QLabel *statusLabel;
-    QPushButton *quitButton;
-    QUdpSocket *udpSocket;
+    QLabel *statusLabel = nullptr;
+    QUdpSocket udpSocket;
     QHostAddress groupAddress;
 };