Use an accessory view instead of an intermediate sheet for OPML export

Mac/MainWindow/OPML/ExportOPMLAccessoryViewController.swift

@@ -0,0 +1,58 @@
+//
+//  ExportOPMLAccessoryViewController.swift
+//  NetNewsWire
+//
+//  Created by Nate Weaver on 2019-10-20.
+//  Copyright © 2019 Ranchero Software. All rights reserved.
+//
+
+import AppKit
+import Account
+
+class ExportOPMLAccessoryViewController: NSViewController {
+
+	@IBOutlet weak var accountPopUpButton: NSPopUpButton!
+
+	var selectedAccount: Account? {
+		accountPopUpButton.selectedItem?.representedObject as? Account
+	}
+
+	init() {
+		super.init(nibName: "ExportOPMLAccessoryView", bundle: nil)
+	}
+
+	// MARK: - NSViewController
+
+	required init?(coder: NSCoder) {
+		preconditionFailure("ExportOPMLAccessoryView.init(coder) not implemented by design.")
+	}
+
+	override func viewDidLoad() {
+		accountPopUpButton.removeAllItems()
+
+		let menu = NSMenu()
+		accountPopUpButton.menu = menu
+
+		for oneAccount in AccountManager.shared.sortedAccounts {
+
+			let oneMenuItem = NSMenuItem()
+			oneMenuItem.title = oneAccount.nameForDisplay
+			oneMenuItem.representedObject = oneAccount
+			menu.addItem(oneMenuItem)
+
+			if oneAccount.accountID == AppDefaults.exportOPMLAccountID {
+				accountPopUpButton.select(oneMenuItem)
+			}
+
+		}
+	}
+
+	@IBAction func accountSelected(_ popUpButton: NSPopUpButton) {
+		NotificationCenter.default.post(name: .ExportOPMLSelectedAccountDidChange, object: self)
+	}
+}
+
+extension Notification.Name {
+	static let ExportOPMLSelectedAccountDidChange = Notification.Name(rawValue: "SelectedAccountDidChange")
+
+}