add minimize to system tray functionality

src/main/java/com/sparrowwallet/sparrow/AppController.java

@@ -92,6 +92,9 @@ public class AppController implements Initializable {
     @FXML
     private Menu fileMenu;
 
+    @FXML
+    private Menu viewMenu;
+
     @FXML
     private Menu toolsMenu;
 
@@ -116,6 +119,9 @@ public class AppController implements Initializable {
     @FXML
     private CheckMenuItem showTxHex;
 
+    @FXML
+    private MenuItem minimizeToTray;
+
     @FXML
     private MenuItem refreshWallet;
 
@@ -285,6 +291,10 @@ public class AppController implements Initializable {
         } else if(platform == org.controlsfx.tools.Platform.WINDOWS) {
             toolsMenu.getItems().removeIf(item -> item.getStyleClass().contains("windowsHide"));
         }
+
+        if(platform == org.controlsfx.tools.Platform.UNIX || !TrayManager.isSupported()) {
+            viewMenu.getItems().remove(minimizeToTray);
+        }
     }
 
     public void showIntroduction(ActionEvent event) {
@@ -953,6 +963,10 @@ public class AppController implements Initializable {
         messageSignDialog.showAndWait();
     }
 
+    public void minimizeToTray(ActionEvent event) {
+        AppServices.get().minimizeStage((Stage)tabs.getScene().getWindow());
+    }
+
     public void refreshWallet(ActionEvent event) {
         Tab selectedTab = tabs.getSelectionModel().getSelectedItem();
         TabData tabData = (TabData)selectedTab.getUserData();

src/main/java/com/sparrowwallet/sparrow/AppServices.java

@@ -9,6 +9,7 @@ import com.sparrowwallet.drongo.psbt.PSBT;
 import com.sparrowwallet.drongo.uri.BitcoinURI;
 import com.sparrowwallet.drongo.wallet.KeystoreSource;
 import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.sparrow.control.TrayManager;
 import com.sparrowwallet.sparrow.event.*;
 import com.sparrowwallet.sparrow.io.Config;
 import com.sparrowwallet.sparrow.io.Device;
@@ -64,6 +65,8 @@ public class AppServices {
 
     private final Map<Window, List<WalletTabData>> walletWindows = new LinkedHashMap<>();
 
+    private TrayManager trayManager;
+
     private static final BooleanProperty onlineProperty = new SimpleBooleanProperty(false);
 
     private ExchangeSource.RatesService ratesService;
@@ -401,6 +404,15 @@ public class AppServices {
         return application;
     }
 
+    public void minimizeStage(Stage stage) {
+        if(trayManager == null) {
+            trayManager = new TrayManager();
+        }
+
+        trayManager.addStage(stage);
+        stage.hide();
+    }
+
     public Map<Wallet, Storage> getOpenWallets() {
         Map<Wallet, Storage> openWallets = new LinkedHashMap<>();
         for(List<WalletTabData> walletTabDataList : walletWindows.values()) {

src/main/java/com/sparrowwallet/sparrow/control/TrayManager.java

@@ -0,0 +1,95 @@
+package com.sparrowwallet.sparrow.control;
+
+import javafx.application.Platform;
+import javafx.stage.Stage;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.imageio.ImageIO;
+import javax.swing.*;
+import java.awt.*;
+import java.awt.image.BaseMultiResolutionImage;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class TrayManager {
+    private static final Logger log = LoggerFactory.getLogger(TrayManager.class);
+
+    private final SystemTray tray;
+    private final TrayIcon trayIcon;
+    private final PopupMenu popupMenu = new PopupMenu();
+
+    public TrayManager() {
+        if(!SystemTray.isSupported()) {
+            throw new UnsupportedOperationException("SystemTray icons are not supported by the current desktop environment.");
+        }
+
+        tray = SystemTray.getSystemTray();
+
+        try {
+            List<Image> imgList = new ArrayList<>();
+            imgList.add(ImageIO.read(getClass().getResource("/image/sparrow-white-small.png")));
+            imgList.add(ImageIO.read(getClass().getResource("/image/sparrow-white-small@2x.png")));
+            imgList.add(ImageIO.read(getClass().getResource("/image/sparrow-white-small@3x.png")));
+            BaseMultiResolutionImage mrImage = new BaseMultiResolutionImage(imgList.toArray(new Image[0]));
+
+            this.trayIcon = new TrayIcon(mrImage, "Sparrow", popupMenu);
+
+            MenuItem miExit = new MenuItem("Quit Sparrow");
+            miExit.addActionListener(e -> {
+                SwingUtilities.invokeLater(() -> { tray.remove(this.trayIcon); });
+                Platform.exit();
+            });
+            this.popupMenu.add(miExit);
+        } catch(IOException e) {
+            log.error("Could not load system tray image", e);
+            throw new IllegalStateException(e);
+        }
+    }
+
+    public void addStage(Stage stage) {
+        EventQueue.invokeLater(() -> {
+            MenuItem miStage = new MenuItem(stage.getTitle());
+            miStage.setFont(Font.decode(null).deriveFont(Font.BOLD));
+            miStage.addActionListener(e -> Platform.runLater(() -> {
+                stage.show();
+                EventQueue.invokeLater(() -> {
+                    popupMenu.remove(miStage);
+
+                    if(popupMenu.getItemCount() == 1) {
+                        Platform.setImplicitExit(true);
+                        SwingUtilities.invokeLater(() -> tray.remove(trayIcon));
+                    }
+                });
+            }));
+            //Make sure it's always at the top
+            this.popupMenu.insert(miStage,popupMenu.getItemCount() - 1);
+
+            if(!isShowing()) {
+                // Keeps the JVM running even if there are no
+                // visible JavaFX Stages, otherwise JVM would
+                // exit and we lose the TrayIcon
+                Platform.setImplicitExit(false);
+
+                SwingUtilities.invokeLater(() -> {
+                    try {
+                        tray.add(this.trayIcon);
+                    } catch(AWTException e) {
+                        log.error("Unable to add system tray icon", e);
+                    }
+                });
+            }
+        });
+    }
+
+    public boolean isShowing() {
+        return Arrays.stream(tray.getTrayIcons()).collect(Collectors.toList()).contains(trayIcon);
+    }
+
+    public static boolean isSupported() {
+        return Desktop.isDesktopSupported() && SystemTray.isSupported();
+    }
+}

src/main/resources/com/sparrowwallet/sparrow/app.fxml

@@ -47,7 +47,7 @@
                 <fx:define>
                     <ToggleGroup fx:id="theme"/>
                 </fx:define>
-                <Menu mnemonicParsing="false" text="View">
+                <Menu fx:id="viewMenu" mnemonicParsing="false" text="View">
                     <items>
                         <Menu mnemonicParsing="false" text="Bitcoin Unit">
                             <items>
@@ -87,6 +87,7 @@
                         <CheckMenuItem fx:id="hideEmptyUsedAddresses" mnemonicParsing="false" text="Hide Empty Used Addresses" onAction="#hideEmptyUsedAddresses"/>
                         <CheckMenuItem fx:id="showTxHex" mnemonicParsing="false" text="Show Transaction Hex" onAction="#showTxHex"/>
                         <SeparatorMenuItem />
+                        <MenuItem fx:id="minimizeToTray" mnemonicParsing="false" text="Minimize to System Tray" accelerator="Shortcut+Y" onAction="#minimizeToTray"/>
                         <MenuItem fx:id="refreshWallet" mnemonicParsing="false" text="Refresh Wallet" accelerator="Shortcut+R" onAction="#refreshWallet"/>
                     </items>
                 </Menu>