Add BlockCounter QML component which handles NotifyBlockTip signal

src/qml/bitcoin.cpp

@@ -127,11 +127,11 @@ int QmlGuiMain(int argc, char* argv[])
 
     handler_message_box.disconnect();
 
-    NodeModel node_model;
+    NodeModel node_model{*node};
     InitExecutor init_executor{*node};
     QObject::connect(&node_model, &NodeModel::requestedInitialize, &init_executor, &InitExecutor::initialize);
     QObject::connect(&node_model, &NodeModel::requestedShutdown, &init_executor, &InitExecutor::shutdown);
-    // QObject::connect(&init_executor, &InitExecutor::initializeResult, &node_model, &NodeModel::initializeResult);
+    QObject::connect(&init_executor, &InitExecutor::initializeResult, &node_model, &NodeModel::initializeResult);
     QObject::connect(&init_executor, &InitExecutor::shutdownResult, qGuiApp, &QGuiApplication::quit, Qt::QueuedConnection);
     // QObject::connect(&init_executor, &InitExecutor::runawayException, &node_model, &NodeModel::handleRunawayException);
 

src/qml/bitcoin_qml.qrc

@@ -1,5 +1,6 @@
 <!DOCTYPE RCC><RCC version="1.0">
     <qresource prefix="/qml">
+        <file>components/BlockCounter.qml</file>
         <file>pages/initerrormessage.qml</file>
         <file>pages/stub.qml</file>
     </qresource>

src/qml/components/BlockCounter.qml

@@ -0,0 +1,21 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+// The BlockCounter component.
+
+import QtQuick 2.12
+import QtQuick.Controls 2.12
+
+Label {
+    property int blockHeight: 0
+    background: Rectangle {
+        color: "black"
+    }
+    color: "orange"
+    padding: 16
+    horizontalAlignment: Text.AlignHCenter
+    verticalAlignment: Text.AlignVCenter
+    font.pixelSize: height / 3
+    text: blockHeight
+}

src/qml/nodemodel.cpp

@@ -4,7 +4,22 @@
 
 #include <qml/nodemodel.h>
 
-#include <QDebug>
+#include <interfaces/node.h>
+#include <validation.h>
+
+NodeModel::NodeModel(interfaces::Node& node)
+    : m_node{node}
+{
+    ConnectToBlockTipSignal();
+}
+
+void NodeModel::setBlockTipHeight(int new_height)
+{
+    if (new_height != m_block_tip_height) {
+        m_block_tip_height = new_height;
+        Q_EMIT blockTipHeightChanged();
+    }
+}
 
 void NodeModel::startNodeInitializionThread()
 {
@@ -15,3 +30,18 @@ void NodeModel::startNodeShutdown()
 {
     Q_EMIT requestedShutdown();
 }
+
+void NodeModel::initializeResult([[maybe_unused]] bool success, interfaces::BlockAndHeaderTipInfo tip_info)
+{
+    // TODO: Handle the `success` parameter,
+    setBlockTipHeight(tip_info.block_height);
+}
+
+void NodeModel::ConnectToBlockTipSignal()
+{
+    assert(!m_handler_notify_block_tip);
+    m_handler_notify_block_tip = m_node.handleNotifyBlockTip(
+        [this](SynchronizationState state, interfaces::BlockTip tip, double verification_progress) {
+            setBlockTipHeight(tip.block_height);
+        });
+}

src/qml/nodemodel.h

@@ -5,20 +5,48 @@
 #ifndef BITCOIN_QML_NODEMODEL_H
 #define BITCOIN_QML_NODEMODEL_H
 
+#include <interfaces/handler.h>
+#include <interfaces/node.h>
+
+#include <memory>
+
 #include <QObject>
 
+namespace interfaces {
+class Node;
+}
+
 /** Model for Bitcoin network client. */
 class NodeModel : public QObject
 {
     Q_OBJECT
+    Q_PROPERTY(int blockTipHeight READ blockTipHeight NOTIFY blockTipHeightChanged)
 
 public:
+    explicit NodeModel(interfaces::Node& node);
+
+    int blockTipHeight() const { return m_block_tip_height; }
+    void setBlockTipHeight(int new_height);
+
     Q_INVOKABLE void startNodeInitializionThread();
     void startNodeShutdown();
 
+public Q_SLOTS:
+    void initializeResult(bool success, interfaces::BlockAndHeaderTipInfo tip_info);
+
 Q_SIGNALS:
+    void blockTipHeightChanged();
     void requestedInitialize();
     void requestedShutdown();
+
+private:
+    // Properties that are exposed to QML.
+    int m_block_tip_height{0};
+
+    interfaces::Node& m_node;
+    std::unique_ptr<interfaces::Handler> m_handler_notify_block_tip;
+
+    void ConnectToBlockTipSignal();
 };
 
 #endif // BITCOIN_QML_NODEMODEL_H

src/qml/pages/stub.qml

@@ -2,8 +2,10 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-import QtQml 2.12
+import QtQuick 2.12
 import QtQuick.Controls 2.12
+import "../components" as BitcoinCoreComponents
+
 
 ApplicationWindow {
     id: appWindow
@@ -13,4 +15,11 @@ ApplicationWindow {
     visible: true
 
     Component.onCompleted: nodeModel.startNodeInitializionThread();
+
+    BitcoinCoreComponents.BlockCounter {
+        id: blockCounter
+        anchors.centerIn: parent
+        height: parent.height / 3
+        blockHeight: nodeModel.blockTipHeight
+    }
 }

src/qt/bitcoin.cpp

@@ -85,7 +85,6 @@ static void RegisterMetaTypes()
 
     qRegisterMetaType<std::function<void()>>("std::function<void()>");
     qRegisterMetaType<QMessageBox::Icon>("QMessageBox::Icon");
-    qRegisterMetaType<interfaces::BlockAndHeaderTipInfo>("interfaces::BlockAndHeaderTipInfo");
 }
 
 static QString GetLangTerritory()

src/qt/main.cpp

@@ -12,6 +12,7 @@
 #include <qt/bitcoin.h>
 #endif // USE_QML
 
+#include <interfaces/node.h>
 #include <logging.h>
 #include <noui.h>
 #include <util/system.h>
@@ -62,6 +63,8 @@ void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, cons
 
 int main(int argc, char* argv[])
 {
+    qRegisterMetaType<interfaces::BlockAndHeaderTipInfo>("interfaces::BlockAndHeaderTipInfo");
+
 #ifdef WIN32
     util::WinCmdLineArgs win_args;
     std::tie(argc, argv) = win_args.get();