Restored confirmation dialog for starting a new campaign

Introduced a NewCampaignConfirmationDialog to prompt users before starting a new campaign, enhancing user decision control. Updated relevant GUI logic in CampaignGUI and added corresponding copyright updates for 2024.

MekHQ/src/mekhq/gui/CampaignGUI.java

@@ -1061,6 +1061,11 @@ private void initMenu() {
      * </p>
      */
     private void handleInAppNewCampaign() {
+        int decision = new NewCampaignConfirmationDialog().YesNoOption();
+        if (decision != JOptionPane.YES_OPTION) {
+            return;
+        }
+
         // Prompt the user to save
         int savePrompt = JOptionPane.showConfirmDialog(null,
             resourceMap.getString("savePrompt.text"),

MekHQ/src/mekhq/gui/dialog/CampaignOptionsDialog.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009-2022 - The MegaMek Team. All Rights Reserved.
+ * Copyright (c) 2009-2024 - The MegaMek Team. All Rights Reserved.
  *
  * This file is part of MekHQ.
  *

MekHQ/src/mekhq/gui/dialog/DataLoadingDialog.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009-2022 - The MegaMek Team. All Rights Reserved.
+ * Copyright (c) 2009-2024 - The MegaMek Team. All Rights Reserved.
  *
  * This file is part of MekHQ.
  *

MekHQ/src/mekhq/gui/dialog/NewCampaignConfirmationDialog.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2021-2024 - The MegaMek Team. All Rights Reserved.
+ *
+ * This file is part of MekHQ.
+ *
+ * MekHQ is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * MekHQ is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MekHQ. If not, see <http://www.gnu.org/licenses/>.
+ */
+package mekhq.gui.dialog;
+
+import javax.swing.*;
+
+public class NewCampaignConfirmationDialog {
+  public int YesNoOption() {
+    return JOptionPane.showConfirmDialog(null,
+        "Are you sure you want to start a new campaign?",
+        "Start New Campaign?",
+        JOptionPane.YES_NO_OPTION);
+  }
+}

MekHQ/src/mekhq/gui/panels/StartupScreenPanel.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 - The MegaMek Team. All Rights Reserved.
+ * Copyright (c) 2022-2024 - The MegaMek Team. All Rights Reserved.
  *
  * This file is part of MekHQ.
  *
@@ -45,7 +45,6 @@
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.FilenameFilter;
-import java.util.Arrays;
 import java.util.List;
 
 public class StartupScreenPanel extends AbstractMHQPanel {