Improve example applications.

* Master: Small coding style change.
* Slave|Master: Have a defined tab order.
* Master: Have a single server address field only.
* Master: Show either coils or holding registers, not both.
* Master: Limit number of possible write values on start address.
* Master: Enable/disable possible items depending on start address.

Change-Id: I2892efe3c4cd1a6f29e26b6b6b2e6b3a3f24ea99
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

6 files changed, 330 insertions, 198 deletions

diff --git a/examples/serialbus/modbus/master/mainwindow.cpp b/examples/serialbus/modbus/master/mainwindow.cpp
index 98cade6..1fb8ee5 100644
--- a/examples/serialbus/modbus/master/mainwindow.cpp
+++ b/examples/serialbus/modbus/master/mainwindow.cpp
@@ -47,6 +47,7 @@
 #include <QtSerialBus/qmodbusrtuserialmaster.h>
 #include <QtCore/qbytearray.h>
 #include <QtCore/qurl.h>
+#include <QtGui/qstandarditemmodel.h>
 #include <QtWidgets/qstatusbar.h>
 
 enum ModbusConnection {
@@ -67,10 +68,14 @@ MainWindow::MainWindow(QWidget *parent)
     initActions();
 
     writeModel = new WriteRegisterModel(this);
+    writeModel->setStartAddress(ui->writeAddress->value());
+    writeModel->setNumberOfValues(ui->writeSize->currentText());
+
     ui->writeValueTable->setModel(writeModel);
+    ui->writeValueTable->hideColumn(2);
     ui->writeValueTable->resizeColumnToContents(0);
-    ui->writeValueTable->horizontalHeader()->setStretchLastSection(true);
-    ui->writeValueTable->verticalHeader()->setSectionResizeMode(QHeaderView::Stretch);
+    connect(writeModel, &WriteRegisterModel::updateViewport, ui->writeValueTable->viewport(),
+        static_cast<void (QWidget::*)()>(&QWidget::update));
 
     ui->readTable->addItem(tr("Coils"), QModbusDataUnit::Coils);
     ui->readTable->addItem(tr("Discrete Inputs"), QModbusDataUnit::DiscreteInputs);
@@ -79,6 +84,31 @@ MainWindow::MainWindow(QWidget *parent)
 
     ui->connectType->setCurrentIndex(0);
     on_connectType_currentIndexChanged(0);
+
+    QStandardItemModel *model = new QStandardItemModel(10, 1, this);
+    for (int i = 0; i < 10; ++i)
+        model->setItem(i, new QStandardItem(QStringLiteral("%1").arg(i + 1)));
+    ui->writeSize->setModel(model);
+    ui->writeSize->setCurrentText("10");
+    connect(ui->writeSize,&QComboBox::currentTextChanged, writeModel,
+        &WriteRegisterModel::setNumberOfValues);
+
+    auto valueChanged = static_cast<void (QSpinBox::*)(int)> (&QSpinBox::valueChanged);
+    connect(ui->writeAddress, valueChanged, writeModel, &WriteRegisterModel::setStartAddress);
+    connect(ui->writeAddress, valueChanged, this, [this, model](int i) {
+        int lastPossibleIndex = 0;
+        const int currentIndex = ui->writeSize->currentIndex();
+        for (int ii = 0; ii < 10; ++ii) {
+            if (ii < (10 - i)) {
+                lastPossibleIndex = ii;
+                model->item(ii)->setEnabled(true);
+            } else {
+                model->item(ii)->setEnabled(false);
+            }
+        }
+        if (currentIndex > lastPossibleIndex)
+            ui->writeSize->setCurrentIndex(lastPossibleIndex);
+    });
 }
 
 MainWindow::~MainWindow()
@@ -212,7 +242,7 @@ void MainWindow::on_readButton_clicked()
     statusBar()->clearMessage();
 
     QModbusReply *reply = modbusDevice->sendReadRequest(dataRequest,
-                                                        ui->readServer->text().toInt());
+                                                        ui->serverEdit->text().toInt());
     // broadcast replies return immediately
     if (reply && reply->isFinished()) {
         delete reply;
@@ -268,8 +298,7 @@ void MainWindow::on_writeButton_clicked()
 
     Q_ASSERT(startAddress >= 0 && startAddress < 10);
     QModbusDataUnit writeUnit(table, startAddress, numberOfEntries);
-    for (int i = startAddress; i < (startAddress + numberOfEntries); i++)
-    {
+    for (int i = startAddress; i < (startAddress + numberOfEntries); i++) {
         if (table == QModbusDataUnit::Coils)
             writeUnit.setValue(i - startAddress, writeModel->m_coils[i]);
         else
@@ -279,7 +308,7 @@ void MainWindow::on_writeButton_clicked()
     statusBar()->clearMessage();
 
     // TODO test for R/W MultipleRegisters is missing
-    QModbusReply *reply = modbusDevice->sendWriteRequest(writeUnit, ui->writeServer->text().toInt());
+    QModbusReply *reply = modbusDevice->sendWriteRequest(writeUnit, ui->serverEdit->text().toInt());
 
     // broadcast replies return immediately
     if (reply && reply->isFinished()) {
@@ -311,3 +340,9 @@ void MainWindow::writeReady()
 
     reply->deleteLater();
 }
+
+void MainWindow::on_writeTable_currentIndexChanged(int index)
+{
+    ui->writeValueTable->setColumnHidden(1, index != 0);
+    ui->writeValueTable->setColumnHidden(2, index != 1);
+}
diff --git a/examples/serialbus/modbus/master/mainwindow.h b/examples/serialbus/modbus/master/mainwindow.h
index 2f6c481..992b687 100644
--- a/examples/serialbus/modbus/master/mainwindow.h
+++ b/examples/serialbus/modbus/master/mainwindow.h
@@ -80,6 +80,7 @@ private slots:
     void writeReady();
 
     void on_connectType_currentIndexChanged(int);
+    void on_writeTable_currentIndexChanged(int);
 
 private:
     Ui::MainWindow *ui;
diff --git a/examples/serialbus/modbus/master/mainwindow.ui b/examples/serialbus/modbus/master/mainwindow.ui
index 11e8e90..f76074e 100644
--- a/examples/serialbus/modbus/master/mainwindow.ui
+++ b/examples/serialbus/modbus/master/mainwindow.ui
@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>517</width>
+    <width>514</width>
     <height>378</height>
    </rect>
   </property>
@@ -20,35 +20,11 @@
    <string>Modbus Master Example</string>
   </property>
   <widget class="QWidget" name="centralWidget">
-   <layout class="QVBoxLayout" name="verticalLayout">
-    <item>
+   <layout class="QGridLayout" name="gridLayout_4">
+    <item row="0" column="0">
      <layout class="QGridLayout" name="gridLayout">
-      <item row="0" column="0">
-       <widget class="QLabel" name="label_111">
-        <property name="text">
-         <string>Connection type:</string>
-        </property>
-       </widget>
-      </item>
-      <item row="0" column="1">
-       <widget class="QComboBox" name="connectType">
-        <property name="text" stdset="0">
-         <string>Connection type:</string>
-        </property>
-        <item>
-         <property name="text">
-          <string>Serial</string>
-         </property>
-        </item>
-        <item>
-         <property name="text">
-          <string>TCP</string>
-         </property>
-        </item>
-       </widget>
-      </item>
-      <item row="0" column="2">
-       <widget class="QLabel" name="label_2">
+      <item row="0" column="5">
+       <widget class="QLabel" name="label_27">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Maximum" vsizetype="Preferred">
           <horstretch>0</horstretch>
@@ -56,18 +32,30 @@
          </sizepolicy>
         </property>
         <property name="text">
-         <string>Port:</string>
+         <string>Server Address:</string>
         </property>
        </widget>
       </item>
-      <item row="0" column="3">
-       <widget class="QLineEdit" name="portEdit">
+      <item row="0" column="7">
+       <widget class="QPushButton" name="connectButton">
         <property name="sizePolicy">
-         <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
+         <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
           <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
+        <property name="text">
+         <string>Connect</string>
+        </property>
+        <property name="checkable">
+         <bool>false</bool>
+        </property>
+        <property name="autoDefault">
+         <bool>false</bool>
+        </property>
+        <property name="default">
+         <bool>true</bool>
+        </property>
        </widget>
       </item>
       <item row="0" column="4">
@@ -83,31 +71,69 @@
         </property>
        </spacer>
       </item>
-      <item row="0" column="5">
-       <widget class="QPushButton" name="connectButton">
+      <item row="0" column="6">
+       <widget class="QSpinBox" name="serverEdit">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Maximum" vsizetype="Fixed">
           <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
-        <property name="text">
-         <string>Connect</string>
+        <property name="minimum">
+         <number>1</number>
         </property>
-        <property name="checkable">
-         <bool>false</bool>
+        <property name="maximum">
+         <number>247</number>
         </property>
-        <property name="autoDefault">
-         <bool>false</bool>
+       </widget>
+      </item>
+      <item row="0" column="1">
+       <widget class="QComboBox" name="connectType">
+        <item>
+         <property name="text">
+          <string>Serial</string>
+         </property>
+        </item>
+        <item>
+         <property name="text">
+          <string>TCP</string>
+         </property>
+        </item>
+       </widget>
+      </item>
+      <item row="0" column="2">
+       <widget class="QLabel" name="label_2">
+        <property name="sizePolicy">
+         <sizepolicy hsizetype="Maximum" vsizetype="Preferred">
+          <horstretch>0</horstretch>
+          <verstretch>0</verstretch>
+         </sizepolicy>
         </property>
-        <property name="default">
-         <bool>true</bool>
+        <property name="text">
+         <string>Port:</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="0">
+       <widget class="QLabel" name="label">
+        <property name="text">
+         <string>Connection type:</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="3">
+       <widget class="QLineEdit" name="portEdit">
+        <property name="sizePolicy">
+         <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
+          <horstretch>0</horstretch>
+          <verstretch>0</verstretch>
+         </sizepolicy>
         </property>
        </widget>
       </item>
      </layout>
     </item>
-    <item>
+    <item row="1" column="0">
      <layout class="QHBoxLayout" name="horizontalLayout_5" stretch="0,0">
       <item>
        <widget class="QFrame" name="frame">
@@ -129,7 +155,14 @@
          </property>
          <item>
           <layout class="QGridLayout" name="gridLayout_2">
-           <item row="5" column="1">
+           <item row="0" column="0">
+            <widget class="QLabel" name="label_7">
+             <property name="text">
+              <string>Start address:</string>
+             </property>
+            </widget>
+           </item>
+           <item row="4" column="1">
             <layout class="QHBoxLayout" name="horizontalLayout_2">
              <item>
               <spacer name="horizontalSpacer_3">
@@ -153,29 +186,7 @@
              </item>
             </layout>
            </item>
-           <item row="0" column="1">
-            <widget class="QSpinBox" name="writeServer">
-             <property name="readOnly">
-              <bool>false</bool>
-             </property>
-             <property name="specialValueText">
-              <string>broadcast</string>
-             </property>
-             <property name="accelerated">
-              <bool>true</bool>
-             </property>
-             <property name="minimum">
-              <number>0</number>
-             </property>
-             <property name="maximum">
-              <number>255</number>
-             </property>
-             <property name="value">
-              <number>1</number>
-             </property>
-            </widget>
-           </item>
-           <item row="3" column="0">
+           <item row="2" column="0">
             <widget class="QLabel" name="label_8">
              <property name="text">
               <string>Number of values:</string>
@@ -183,27 +194,13 @@
             </widget>
            </item>
            <item row="1" column="0">
-            <widget class="QLabel" name="label_7">
-             <property name="text">
-              <string>Address:</string>
-             </property>
-            </widget>
-           </item>
-           <item row="1" column="1">
-            <widget class="QSpinBox" name="writeAddress">
-             <property name="maximum">
-              <number>9</number>
-             </property>
-            </widget>
-           </item>
-           <item row="2" column="0">
             <widget class="QLabel" name="label_6">
              <property name="text">
               <string>Table:</string>
              </property>
             </widget>
            </item>
-           <item row="2" column="1">
+           <item row="1" column="1">
             <widget class="QComboBox" name="writeTable">
              <item>
               <property name="text">
@@ -217,18 +214,18 @@
              </item>
             </widget>
            </item>
-           <item row="0" column="0">
-            <widget class="QLabel" name="label_10">
-             <property name="text">
-              <string>Server Address:</string>
+           <item row="0" column="1">
+            <widget class="QSpinBox" name="writeAddress">
+             <property name="maximum">
+              <number>9</number>
              </property>
             </widget>
            </item>
-           <item row="4" column="0" colspan="2">
-            <widget class="QTableView" name="writeValueTable"/>
-           </item>
-           <item row="3" column="1">
+           <item row="2" column="1">
             <widget class="QComboBox" name="writeSize">
+             <property name="currentIndex">
+              <number>9</number>
+             </property>
              <item>
               <property name="text">
                <string>1</string>
@@ -281,6 +278,31 @@
              </item>
             </widget>
            </item>
+           <item row="3" column="0" colspan="2">
+            <widget class="QTreeView" name="writeValueTable">
+             <property name="showDropIndicator" stdset="0">
+              <bool>true</bool>
+             </property>
+             <property name="alternatingRowColors">
+              <bool>true</bool>
+             </property>
+             <property name="rootIsDecorated">
+              <bool>false</bool>
+             </property>
+             <property name="uniformRowHeights">
+              <bool>true</bool>
+             </property>
+             <property name="itemsExpandable">
+              <bool>false</bool>
+             </property>
+             <property name="expandsOnDoubleClick">
+              <bool>false</bool>
+             </property>
+             <attribute name="headerVisible">
+              <bool>true</bool>
+             </attribute>
+            </widget>
+           </item>
           </layout>
          </item>
         </layout>
@@ -303,7 +325,61 @@
         <layout class="QHBoxLayout" name="horizontalLayout_4">
          <item>
           <layout class="QGridLayout" name="gridLayout_3">
-           <item row="3" column="1">
+           <item row="3" column="0">
+            <widget class="QLabel" name="label_9">
+             <property name="text">
+              <string>Values:</string>
+             </property>
+            </widget>
+           </item>
+           <item row="4" column="0">
+            <spacer name="verticalSpacer_2">
+             <property name="orientation">
+              <enum>Qt::Vertical</enum>
+             </property>
+             <property name="sizeHint" stdset="0">
+              <size>
+               <width>20</width>
+               <height>40</height>
+              </size>
+             </property>
+            </spacer>
+           </item>
+           <item row="2" column="0">
+            <widget class="QLabel" name="label_5">
+             <property name="text">
+              <string>Number of values:</string>
+             </property>
+            </widget>
+           </item>
+           <item row="3" column="1" rowspan="2">
+            <widget class="QListWidget" name="readValue"/>
+           </item>
+           <item row="1" column="0">
+            <widget class="QLabel" name="label_3">
+             <property name="text">
+              <string>Table:</string>
+             </property>
+            </widget>
+           </item>
+           <item row="1" column="1">
+            <widget class="QComboBox" name="readTable"/>
+           </item>
+           <item row="0" column="1">
+            <widget class="QSpinBox" name="readAddress">
+             <property name="maximum">
+              <number>9</number>
+             </property>
+            </widget>
+           </item>
+           <item row="0" column="0">
+            <widget class="QLabel" name="label_4">
+             <property name="text">
+              <string>Start address:</string>
+             </property>
+            </widget>
+           </item>
+           <item row="2" column="1">
             <widget class="QComboBox" name="readSize">
              <item>
               <property name="text">
@@ -357,7 +433,7 @@
              </item>
             </widget>
            </item>
-           <item row="6" column="1">
+           <item row="5" column="1">
             <layout class="QHBoxLayout" name="horizontalLayout">
              <item>
               <spacer name="horizontalSpacer_2">
@@ -387,89 +463,6 @@
              </item>
             </layout>
            </item>
-           <item row="1" column="1">
-            <widget class="QSpinBox" name="readAddress">
-             <property name="maximum">
-              <number>9</number>
-             </property>
-            </widget>
-           </item>
-           <item row="0" column="0">
-            <widget class="QLabel" name="label_11">
-             <property name="text">
-              <string>Server Address:</string>
-             </property>
-            </widget>
-           </item>
-           <item row="2" column="1">
-            <widget class="QComboBox" name="readTable"/>
-           </item>
-           <item row="1" column="0">
-            <widget class="QLabel" name="label_4">
-             <property name="text">
-              <string>Start address:</string>
-             </property>
-            </widget>
-           </item>
-           <item row="0" column="1">
-            <widget class="QSpinBox" name="readServer">
-             <property name="readOnly">
-              <bool>false</bool>
-             </property>
-             <property name="specialValueText">
-              <string>broadcast</string>
-             </property>
-             <property name="accelerated">
-              <bool>true</bool>
-             </property>
-             <property name="minimum">
-              <number>0</number>
-             </property>
-             <property name="maximum">
-              <number>255</number>
-             </property>
-             <property name="value">
-              <number>1</number>
-             </property>
-            </widget>
-           </item>
-           <item row="4" column="0">
-            <widget class="QLabel" name="label_9">
-             <property name="text">
-              <string>Values:</string>
-             </property>
-            </widget>
-           </item>
-           <item row="3" column="0">
-            <widget class="QLabel" name="label_5">
-             <property name="text">
-              <string>Number of values:</string>
-             </property>
-            </widget>
-           </item>
-           <item row="5" column="0">
-            <spacer name="verticalSpacer_2">
-             <property name="orientation">
-              <enum>Qt::Vertical</enum>
-             </property>
-             <property name="sizeHint" stdset="0">
-              <size>
-               <width>20</width>
-               <height>40</height>
-              </size>
-             </property>
-            </spacer>
-           </item>
-           <item row="4" column="1" rowspan="2">
-            <widget class="QListWidget" name="readValue"/>
-           </item>
-           <item row="2" column="0">
-            <widget class="QLabel" name="label_3">
-             <property name="text">
-              <string>Table:</string>
-             </property>
-            </widget>
-           </item>
           </layout>
          </item>
         </layout>
@@ -485,7 +478,7 @@
     <rect>
      <x>0</x>
      <y>0</y>
-     <width>517</width>
+     <width>514</width>
      <height>21</height>
     </rect>
    </property>
@@ -545,6 +538,22 @@
   </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
+ <tabstops>
+  <tabstop>connectType</tabstop>
+  <tabstop>portEdit</tabstop>
+  <tabstop>serverEdit</tabstop>
+  <tabstop>connectButton</tabstop>
+  <tabstop>writeAddress</tabstop>
+  <tabstop>writeTable</tabstop>
+  <tabstop>writeSize</tabstop>
+  <tabstop>writeValueTable</tabstop>
+  <tabstop>writeButton</tabstop>
+  <tabstop>readAddress</tabstop>
+  <tabstop>readTable</tabstop>
+  <tabstop>readSize</tabstop>
+  <tabstop>readValue</tabstop>
+  <tabstop>readButton</tabstop>
+ </tabstops>
  <resources>
   <include location="master.qrc"/>
  </resources>
diff --git a/examples/serialbus/modbus/master/writeregistermodel.cpp b/examples/serialbus/modbus/master/writeregistermodel.cpp
index d3656fe..f0ed26e 100644
--- a/examples/serialbus/modbus/master/writeregistermodel.cpp
+++ b/examples/serialbus/modbus/master/writeregistermodel.cpp
@@ -41,7 +41,11 @@
 #include "writeregistermodel.h"
 
 #define ROW_COUNT 10
-#define COLUMN_COUNT 2
+#define COLUMN_COUNT 3
+
+#define COLUMN_NUM 0
+#define COLUMN_COILS 1
+#define COLUMN_HOLDING 2
 
 WriteRegisterModel::WriteRegisterModel(QObject *parent)
     : QAbstractTableModel(parent),
@@ -67,9 +71,13 @@ QVariant WriteRegisterModel::data(const QModelIndex &index, int role) const
     Q_ASSERT(m_coils.count() == ROW_COUNT);
     Q_ASSERT(m_holdingRegisters.count() == ROW_COUNT);
 
-    if (index.column() == 0 && role == Qt::CheckStateRole) // coils
+    if (index.column() == COLUMN_NUM && role == Qt::DisplayRole)
+        return QString::number(index.row());
+
+    if (index.column() == COLUMN_COILS && role == Qt::CheckStateRole) // coils
         return m_coils.at(index.row()) ? Qt::Checked : Qt::Unchecked;
-    else if (index.column() == 1 && role != Qt::CheckStateRole) //holding registers
+
+    else if (index.column() == COLUMN_HOLDING && role == Qt::DisplayRole) //holding registers
         return QString("0x%1").arg(QString::number(m_holdingRegisters.at(index.row()), 16));
 
     return QVariant();
@@ -82,13 +90,18 @@ QVariant WriteRegisterModel::headerData(int section, Qt::Orientation orientation
         return QVariant();
 
     if (orientation == Qt::Horizontal) {
-        if (section == 0)
+        switch (section) {
+        case COLUMN_NUM:
+            return QStringLiteral("#");
+        case COLUMN_COILS:
             return QStringLiteral("Coils  ");
-        else
+        case COLUMN_HOLDING:
             return QStringLiteral("Holding Registers");
-    } else {
-        return QString::number(section);
+        default:
+            break;
+        }
     }
+    return QVariant();
 }
 
 bool WriteRegisterModel::setData(const QModelIndex &index, const QVariant &value, int role)
@@ -99,12 +112,14 @@ bool WriteRegisterModel::setData(const QModelIndex &index, const QVariant &value
     Q_ASSERT(m_coils.count() == ROW_COUNT);
     Q_ASSERT(m_holdingRegisters.count() == ROW_COUNT);
 
-    if (index.column() == 0 && role == Qt::CheckStateRole) { // coils
+    if (index.column() == COLUMN_COILS && role == Qt::CheckStateRole) { // coils
         Qt::CheckState s = static_cast<Qt::CheckState>(value.toUInt());
         s == Qt::Checked ? m_coils.setBit(index.row()) : m_coils.clearBit(index.row());
         emit dataChanged(index, index);
         return true;
-    } else if (index.column() == 1 && Qt::EditRole) { // holding registers
+    }
+
+    if (index.column() == COLUMN_HOLDING && Qt::EditRole) { // holding registers
         bool result = false;
         quint16 newValue = value.toString().toUShort(&result, 16);
         if (result)
@@ -119,15 +134,29 @@ bool WriteRegisterModel::setData(const QModelIndex &index, const QVariant &value
 
 Qt::ItemFlags WriteRegisterModel::flags(const QModelIndex &index) const
 {
-    if (!index.isValid() ||  index.row() >= ROW_COUNT || index.column() >= COLUMN_COUNT)
+    if (!index.isValid() || index.row() >= ROW_COUNT || index.column() >= COLUMN_COUNT)
         return QAbstractTableModel::flags(index);
 
-    if (index.column() == 0) //coils
-        return QAbstractTableModel::flags(index) | Qt::ItemIsUserCheckable;
+    Qt::ItemFlags flags = QAbstractTableModel::flags(index);
+    if ((index.row() < m_address) || (index.row() >= (m_address + m_number)))
+        flags &= ~Qt::ItemIsEnabled;
+
+    if (index.column() == COLUMN_COILS) //coils
+        return flags | Qt::ItemIsUserCheckable;
+    if (index.column() == COLUMN_HOLDING) //holding registers
+        return flags | Qt::ItemIsEditable;
 
-    if (index.column() == 1) //holding registers
-        return QAbstractTableModel::flags(index) | Qt::ItemIsEditable;
+    return flags;
+}
 
-    return QAbstractTableModel::flags(index);
+void WriteRegisterModel::setStartAddress(int address)
+{
+    m_address = address;
+    emit updateViewport();
 }
 
+void WriteRegisterModel::setNumberOfValues(const QString &number)
+{
+    m_number = number.toInt();
+    emit updateViewport();
+}
diff --git a/examples/serialbus/modbus/master/writeregistermodel.h b/examples/serialbus/modbus/master/writeregistermodel.h
index 101d6d9..3705df9 100644
--- a/examples/serialbus/modbus/master/writeregistermodel.h
+++ b/examples/serialbus/modbus/master/writeregistermodel.h
@@ -43,9 +43,12 @@
 
 #include <QtCore/qabstractitemmodel.h>
 #include <QtCore/qbitarray.h>
+#include <QtCore/qobject.h>
 
 class WriteRegisterModel : public QAbstractTableModel
 {
+    Q_OBJECT
+
 public:
     WriteRegisterModel(QObject* parent = 0);
 
@@ -58,7 +61,16 @@ public:
 
     Qt::ItemFlags flags(const QModelIndex &index) const Q_DECL_OVERRIDE;
 
+public slots:
+    void setStartAddress(int address);
+    void setNumberOfValues(const QString &number);
+
+signals:
+    void updateViewport();
+
 public:
+    int m_number;
+    int m_address;
     QBitArray m_coils;
     QVector<quint16> m_holdingRegisters;
 };
diff --git a/examples/serialbus/modbus/slave/mainwindow.ui b/examples/serialbus/modbus/slave/mainwindow.ui
index c9ad757..61a0ba4 100644
--- a/examples/serialbus/modbus/slave/mainwindow.ui
+++ b/examples/serialbus/modbus/slave/mainwindow.ui
@@ -772,6 +772,52 @@
   </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
+ <tabstops>
+  <tabstop>connectType</tabstop>
+  <tabstop>portEdit</tabstop>
+  <tabstop>serverEdit</tabstop>
+  <tabstop>connectButton</tabstop>
+  <tabstop>coils_0</tabstop>
+  <tabstop>disc_0</tabstop>
+  <tabstop>inReg_0</tabstop>
+  <tabstop>holdReg_0</tabstop>
+  <tabstop>coils_1</tabstop>
+  <tabstop>disc_1</tabstop>
+  <tabstop>inReg_1</tabstop>
+  <tabstop>holdReg_1</tabstop>
+  <tabstop>coils_2</tabstop>
+  <tabstop>disc_2</tabstop>
+  <tabstop>inReg_2</tabstop>
+  <tabstop>holdReg_2</tabstop>
+  <tabstop>coils_3</tabstop>
+  <tabstop>disc_3</tabstop>
+  <tabstop>inReg_3</tabstop>
+  <tabstop>holdReg_3</tabstop>
+  <tabstop>coils_4</tabstop>
+  <tabstop>disc_4</tabstop>
+  <tabstop>inReg_4</tabstop>
+  <tabstop>holdReg_4</tabstop>
+  <tabstop>coils_5</tabstop>
+  <tabstop>disc_5</tabstop>
+  <tabstop>inReg_5</tabstop>
+  <tabstop>holdReg_5</tabstop>
+  <tabstop>coils_6</tabstop>
+  <tabstop>disc_6</tabstop>
+  <tabstop>inReg_6</tabstop>
+  <tabstop>holdReg_6</tabstop>
+  <tabstop>coils_7</tabstop>
+  <tabstop>disc_7</tabstop>
+  <tabstop>inReg_7</tabstop>
+  <tabstop>holdReg_7</tabstop>
+  <tabstop>coils_8</tabstop>
+  <tabstop>disc_8</tabstop>
+  <tabstop>inReg_8</tabstop>
+  <tabstop>holdReg_8</tabstop>
+  <tabstop>coils_9</tabstop>
+  <tabstop>disc_9</tabstop>
+  <tabstop>inReg_9</tabstop>
+  <tabstop>holdReg_9</tabstop>
+ </tabstops>
  <resources>
   <include location="slave.qrc"/>
  </resources>