[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.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/qt/transactiontablemodel.cpp b/src/qt/transactiontablemodel.cpp
index b9fcd0d6b0..e34238d805 100644
--- a/src/qt/transactiontablemodel.cpp
+++ b/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));
 }