[Qt] New status bar Unit Display Control and related changes.

- New status bar control shows the current Unit of Display.
  When clicked (left,or right button) it shows a context menu
  that allows the user to switch the current Unit of Display (BTC, mBTC, uBTC)
- Recent Requests and Transaction Table headers are now updated when
  unit of display is changed, because their "Amount" column now displays the
  current unit of display.
- Takes care of issue #3970 Units in transaction export csv file.
- Small refactors for reusability.
- Demo Video https://www.youtube.com/watch?v=wwcr0Yh68go&list=UUG3jF2hgofmLWP0tRPisQAQ
- changes after Diapolo's feedback. Have not been able to build after last pool, issues with boost on MacOSX, will test on Ubuntu these changes.
- removed return statement on switch
- renamed onDisplayUnitsChanged(int) to updateDisplayUnit(int)
- now getAmountColumnTitle(int unit) takes a simple unit parameter. moved to BitcoinUnits.

src/qt/bitcoingui.cpp

@@ -28,6 +28,7 @@
 
 #include <iostream>
 
+#include <QAction>
 #include <QApplication>
 #include <QDateTime>
 #include <QDesktopWidget>
@@ -39,6 +40,7 @@
 #include <QMenuBar>
 #include <QMessageBox>
 #include <QMimeData>
+#include <QPoint>
 #include <QProgressBar>
 #include <QProgressDialog>
 #include <QSettings>
@@ -49,6 +51,8 @@
 #include <QToolBar>
 #include <QVBoxLayout>
 
+
+
 #if QT_VERSION < 0x050000
 #include <QUrl>
 #include <QTextDocument>
@@ -156,10 +160,13 @@ BitcoinGUI::BitcoinGUI(bool fIsTestnet, QWidget *parent) :
     QHBoxLayout *frameBlocksLayout = new QHBoxLayout(frameBlocks);
     frameBlocksLayout->setContentsMargins(3,0,3,0);
     frameBlocksLayout->setSpacing(3);
+    unitDisplayControl = new UnitDisplayStatusBarControl();
     labelEncryptionIcon = new QLabel();
     labelConnectionsIcon = new QLabel();
     labelBlocksIcon = new QLabel();
     frameBlocksLayout->addStretch();
+    frameBlocksLayout->addWidget(unitDisplayControl);
+    frameBlocksLayout->addStretch();
     frameBlocksLayout->addWidget(labelEncryptionIcon);
     frameBlocksLayout->addStretch();
     frameBlocksLayout->addWidget(labelConnectionsIcon);
@@ -420,6 +427,8 @@ void BitcoinGUI::setClientModel(ClientModel *clientModel)
             walletFrame->setClientModel(clientModel);
         }
 #endif
+
+        this->unitDisplayControl->setOptionsModel(clientModel->getOptionsModel());
     }
 }
 
@@ -1000,3 +1009,72 @@ void BitcoinGUI::unsubscribeFromCoreSignals()
     // Disconnect signals from client
     uiInterface.ThreadSafeMessageBox.disconnect(boost::bind(ThreadSafeMessageBox, this, _1, _2, _3));
 }
+
+UnitDisplayStatusBarControl::UnitDisplayStatusBarControl():QLabel()
+{
+    optionsModel = 0;
+    createContextMenu();
+    setStyleSheet("font:11pt; color: #333333");
+    setToolTip(tr("Unit to show amounts in. Click to select another unit."));
+}
+
+/** So that it responds to left-button clicks */
+void UnitDisplayStatusBarControl::mousePressEvent(QMouseEvent *event)
+{
+    onDisplayUnitsClicked(event->pos());
+}
+
+/** Creates context menu, its actions, and wires up all the relevant signals for mouse events. */
+void UnitDisplayStatusBarControl::createContextMenu()
+{
+    menu = new QMenu();
+    foreach(BitcoinUnits::Unit u, BitcoinUnits::availableUnits())
+    {
+        QAction *menuAction = new QAction(QString(BitcoinUnits::name(u)), this);
+        menuAction->setData(QVariant(u));
+        menu->addAction(menuAction);
+    }
+    connect(menu,SIGNAL(triggered(QAction*)),this,SLOT(onMenuSelection(QAction*)));
+
+    // what happens on right click.
+    setContextMenuPolicy(Qt::CustomContextMenu);
+    connect(this,SIGNAL(customContextMenuRequested(const QPoint&)),this,SLOT(onDisplayUnitsClicked(const QPoint&)));
+}
+
+/** Lets the control know about the Options Model (and its signals) */
+void UnitDisplayStatusBarControl::setOptionsModel(OptionsModel *optionsModel)
+{
+    if (optionsModel)
+    {
+        this->optionsModel = optionsModel;
+
+        // be aware of a display unit change reported by the OptionsModel object.
+        connect(optionsModel,SIGNAL(displayUnitChanged(int)),this,SLOT(updateDisplayUnit(int)));
+
+        // initialize the display units label with the current value in the model.
+        updateDisplayUnit(optionsModel->getDisplayUnit());
+    }
+}
+
+/** When Display Units are changed on OptionsModel it will refresh the display text of the control on the status bar */
+void UnitDisplayStatusBarControl::updateDisplayUnit(int newUnits)
+{
+    setText(BitcoinUnits::name(newUnits));
+}
+
+/** Shows context menu with Display Unit options by the mouse coordinates */
+void UnitDisplayStatusBarControl::onDisplayUnitsClicked(const QPoint& point)
+{
+    QPoint globalPos = mapToGlobal(point);
+    menu->exec(globalPos);
+}
+
+/** Tells underlying optionsModel to update its current display unit. */
+void UnitDisplayStatusBarControl::onMenuSelection(QAction* action)
+{
+    if (action)
+    {
+        optionsModel->setDisplayUnit(action->data());
+    }
+}
+

src/qt/bitcoingui.h

@@ -9,12 +9,16 @@
 #include "config/bitcoin-config.h"
 #endif
 
+#include <QLabel>
 #include <QMainWindow>
 #include <QMap>
+#include <QMenu>
+#include <QPoint>
 #include <QSystemTrayIcon>
 
 class ClientModel;
 class Notificator;
+class OptionsModel;
 class RPCConsole;
 class SendCoinsRecipient;
 class WalletFrame;
@@ -22,9 +26,13 @@ class WalletModel;
 
 class CWallet;
 
+class UnitDisplayStatusBarControl;
+
 QT_BEGIN_NAMESPACE
 class QAction;
 class QLabel;
+class QMenu;
+class QPoint;
 class QProgressBar;
 class QProgressDialog;
 QT_END_NAMESPACE
@@ -69,6 +77,7 @@ private:
     ClientModel *clientModel;
     WalletFrame *walletFrame;
 
+    UnitDisplayStatusBarControl *unitDisplayControl;
     QLabel *labelEncryptionIcon;
     QLabel *labelConnectionsIcon;
     QLabel *labelBlocksIcon;
@@ -198,4 +207,32 @@ private slots:
     void showProgress(const QString &title, int nProgress);
 };
 
+class UnitDisplayStatusBarControl : public QLabel
+{
+    Q_OBJECT
+
+public:
+    explicit UnitDisplayStatusBarControl();
+    /** Lets the control know about the Options Model (and its signals) */
+    void setOptionsModel(OptionsModel *optionsModel);
+
+protected:
+    /** So that it responds to left-button clicks */
+    void mousePressEvent(QMouseEvent *event);
+
+private:
+    OptionsModel *optionsModel;
+    QMenu* menu;
+    /** Shows context menu with Display Unit options by the mouse coordinates */
+    void onDisplayUnitsClicked(const QPoint& point);
+    /** Creates context menu, its actions, and wires up all the relevant signals for mouse events. */
+    void createContextMenu();
+
+private slots:
+    /** When Display Units are changed on OptionsModel it will refresh the display text of the control on the status bar */
+    void updateDisplayUnit(int newUnits);
+    /** Tells underlying optionsModel to update its current display unit. */
+    void onMenuSelection(QAction* action);
+};
+
 #endif // BITCOINGUI_H

src/qt/bitcoinunits.cpp

@@ -169,6 +169,16 @@ bool BitcoinUnits::parse(int unit, const QString &value, qint64 *val_out)
     return ok;
 }
 
+QString BitcoinUnits::getAmountColumnTitle(int unit)
+{
+    QString amountTitle = QObject::tr("Amount");
+    if (BitcoinUnits::valid(unit))
+    {
+        amountTitle += " ("+BitcoinUnits::name(unit) + ")";
+    }
+    return amountTitle;
+}
+
 int BitcoinUnits::rowCount(const QModelIndex &parent) const
 {
     Q_UNUSED(parent);

src/qt/bitcoinunits.h

@@ -54,6 +54,8 @@ public:
     static QString formatWithUnit(int unit, qint64 amount, bool plussign=false);
     //! Parse string to coin amount
     static bool parse(int unit, const QString &value, qint64 *val_out);
+    //! Gets title for amount column including current display unit if optionsModel reference available */
+    static QString getAmountColumnTitle(int unit);
     ///@}
 
     //! @name AbstractListModel implementation

src/qt/optionsmodel.cpp

@@ -308,9 +308,7 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
             break;
 #endif
         case DisplayUnit:
-            nDisplayUnit = value.toInt();
-            settings.setValue("nDisplayUnit", nDisplayUnit);
-            emit displayUnitChanged(nDisplayUnit);
+            setDisplayUnit(value);
             break;
         case DisplayAddresses:
             bDisplayAddresses = value.toBool();
@@ -356,11 +354,24 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
             break;
         }
     }
+
     emit dataChanged(index, index);
 
     return successful;
 }
 
+/** Updates current unit in memory, settings and emits displayUnitChanged(newUnit) signal */
+void OptionsModel::setDisplayUnit(const QVariant &value)
+{
+    if (!value.isNull())
+    {
+        QSettings settings;
+        nDisplayUnit = value.toInt();
+        settings.setValue("nDisplayUnit", nDisplayUnit);
+        emit displayUnitChanged(nDisplayUnit);
+    }
+}
+
 bool OptionsModel::getProxySettings(QNetworkProxy& proxy) const
 {
     // Directly query current base proxy, because

src/qt/optionsmodel.h

@@ -52,6 +52,8 @@ public:
     int rowCount(const QModelIndex & parent = QModelIndex()) const;
     QVariant data(const QModelIndex & index, int role = Qt::DisplayRole) const;
     bool setData(const QModelIndex & index, const QVariant & value, int role = Qt::EditRole);
+    /** Updates current unit in memory, settings and emits displayUnitChanged(newUnit) signal */
+    void setDisplayUnit(const QVariant &value);
 
     /* Explicit getters */
     bool getMinimizeToTray() { return fMinimizeToTray; }

src/qt/recentrequeststablemodel.cpp

@@ -21,7 +21,9 @@ RecentRequestsTableModel::RecentRequestsTableModel(CWallet *wallet, WalletModel
         addNewRequest(request);
 
     /* These columns must match the indices in the ColumnIndex enumeration */
-    columns << tr("Date") << tr("Label") << tr("Message") << tr("Amount");
+    columns << tr("Date") << tr("Label") << tr("Message") << getAmountTitle();
+
+    connect(walletModel->getOptionsModel(), SIGNAL(displayUnitChanged(int)), this, SLOT(updateDisplayUnit()));
 }
 
 RecentRequestsTableModel::~RecentRequestsTableModel()
@@ -101,6 +103,24 @@ QVariant RecentRequestsTableModel::headerData(int section, Qt::Orientation orien
     return QVariant();
 }
 
+/** Updates the column title to "Amount (DisplayUnit)" and emits headerDataChanged() signal for table headers to react. */
+void RecentRequestsTableModel::updateAmountColumnTitle()
+{
+    columns[Amount] = getAmountTitle();
+    emit headerDataChanged(Qt::Horizontal,Amount,Amount);
+}
+
+/** Gets title for amount column including current display unit if optionsModel reference available. */
+QString RecentRequestsTableModel::getAmountTitle()
+{
+    QString amountTitle = tr("Amount");
+    if (this->walletModel->getOptionsModel() != NULL)
+    {
+        amountTitle += " ("+BitcoinUnits::name(this->walletModel->getOptionsModel()->getDisplayUnit()) + ")";
+    }
+    return amountTitle;
+}
+
 QModelIndex RecentRequestsTableModel::index(int row, int column, const QModelIndex &parent) const
 {
     Q_UNUSED(parent);
@@ -185,6 +205,11 @@ void RecentRequestsTableModel::sort(int column, Qt::SortOrder order)
     emit dataChanged(index(0, 0, QModelIndex()), index(list.size() - 1, NUMBER_OF_COLUMNS - 1, QModelIndex()));
 }
 
+void RecentRequestsTableModel::updateDisplayUnit()
+{
+    updateAmountColumnTitle();
+}
+
 bool RecentRequestEntryLessThan::operator()(RecentRequestEntry &left, RecentRequestEntry &right) const
 {
     RecentRequestEntry *pLeft = &left;

src/qt/recentrequeststablemodel.h

@@ -91,12 +91,18 @@ public:
 
 public slots:
     void sort(int column, Qt::SortOrder order = Qt::AscendingOrder);
+    void updateDisplayUnit();
 
 private:
     WalletModel *walletModel;
     QStringList columns;
     QList<RecentRequestEntry> list;
     int64_t nReceiveRequestsMaxId;
+
+    /** Updates the column title to "Amount (DisplayUnit)" and emits headerDataChanged() signal for table headers to react. */
+    void updateAmountColumnTitle();
+    /** Gets title for amount column including current display unit if optionsModel reference available. */
+    QString getAmountTitle();
 };
 
 #endif

src/qt/transactiontablemodel.cpp

@@ -235,8 +235,7 @@ TransactionTableModel::TransactionTableModel(CWallet* wallet, WalletModel *paren
         walletModel(parent),
         priv(new TransactionTablePriv(wallet, this))
 {
-    columns << QString() << tr("Date") << tr("Type") << tr("Address") << tr("Amount");
-
+    columns << QString() << tr("Date") << tr("Type") << tr("Address") << BitcoinUnits::getAmountColumnTitle(walletModel->getOptionsModel()->getDisplayUnit());
     priv->refreshWallet();
 
     connect(walletModel->getOptionsModel(), SIGNAL(displayUnitChanged(int)), this, SLOT(updateDisplayUnit()));
@@ -247,6 +246,13 @@ TransactionTableModel::~TransactionTableModel()
     delete priv;
 }
 
+/** Updates the column title to "Amount (DisplayUnit)" and emits headerDataChanged() signal for table headers to react. */
+void TransactionTableModel::updateAmountColumnTitle()
+{
+    columns[Amount] = BitcoinUnits::getAmountColumnTitle(walletModel->getOptionsModel()->getDisplayUnit());
+    emit headerDataChanged(Qt::Horizontal,Amount,Amount);
+}
+
 void TransactionTableModel::updateTransaction(const QString &hash, int status)
 {
     uint256 updated;
@@ -624,5 +630,6 @@ QModelIndex TransactionTableModel::index(int row, int column, const QModelIndex
 void TransactionTableModel::updateDisplayUnit()
 {
     // emit dataChanged to update Amount column with the current unit
+    updateAmountColumnTitle();
     emit dataChanged(index(0, Amount), index(priv->size()-1, Amount));
 }

src/qt/transactiontablemodel.h

@@ -87,6 +87,8 @@ public slots:
     void updateTransaction(const QString &hash, int status);
     void updateConfirmations();
     void updateDisplayUnit();
+    /** Updates the column title to "Amount (DisplayUnit)" and emits headerDataChanged() signal for table headers to react. */
+    void updateAmountColumnTitle();
 
     friend class TransactionTablePriv;
 };

src/qt/transactionview.cpp

@@ -309,7 +309,7 @@ void TransactionView::exportClicked()
     writer.addColumn(tr("Type"), TransactionTableModel::Type, Qt::EditRole);
     writer.addColumn(tr("Label"), 0, TransactionTableModel::LabelRole);
     writer.addColumn(tr("Address"), 0, TransactionTableModel::AddressRole);
-    writer.addColumn(tr("Amount"), 0, TransactionTableModel::FormattedAmountRole);
+    writer.addColumn(BitcoinUnits::getAmountColumnTitle(model->getOptionsModel()->getDisplayUnit()), 0, TransactionTableModel::FormattedAmountRole);
     writer.addColumn(tr("ID"), 0, TransactionTableModel::TxIDRole);
 
     if(!writer.write()) {