Swift - 嵌套导航控制器缺少“编辑”按钮

Question

我有一个图书馆应用程序，当您点击每个图书馆时，它会拉出书架列表，点击后会拉出每个书架上的书籍列表。我在导航栏中仅在显示书籍列表的视图上放置“+”时遇到问题，以便能够添加书籍。我已经尝试以编程方式以及使用情节提要添加它，但是，尽管应用程序可以正确构建和运行，但按钮永远不会出现。任何与此相关的建议都会很棒！

下面是我的 bookTableViewController 代码：

import UIKit

class bookTableViewController: UITableViewController {

@IBOutlet var addBookButton: UIBarButtonItem!

var currentShelf = Shelf()

override func viewDidLoad() {
    super.viewDidLoad()

    self.navigationItem.title = "Shelf"

    navigationItem.rightBarButtonItem?.title = "Add"

    self.tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")

}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return currentShelf.allBooksOnShelf.count
}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    var cell:UITableViewCell = self.tableView.dequeueReusableCellWithIdentifier("cell") as UITableViewCell

    cell.textLabel.text = currentShelf.allBooksOnShelf[indexPath.row].bookName

    return cell
}

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

    if currentShelf.allBooksOnShelf[indexPath.row].hasBeenRead == false{
        currentShelf.allBooksOnShelf[indexPath.row].hasBeenRead = true
    var alert = UIAlertController(title: "Read Book", message: "Thanks For Reading!", preferredStyle: UIAlertControllerStyle.Alert)
    alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
    self.presentViewController(alert, animated: true, completion: nil)

    }
    else{
        currentShelf.allBooksOnShelf[indexPath.row].hasBeenRead = false
        var alert = UIAlertController(title: "Read Book", message: "You Just UnRead A Book...", preferredStyle: UIAlertControllerStyle.Alert)
        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
        self.presentViewController(alert, animated: true, completion: nil)

    }

}

override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {

    if editingStyle == .Delete {

        // Delete the row from the data source
        currentShelf.allBooksOnShelf.removeAtIndex(indexPath.row)
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)

    } else if editingStyle == .Insert {
        // Create a new instance of the appropriate class, insert it into the array, and add a        new row to the table view
    }
    }


 }

这是我用来从 Shelf Table View Controller 推送到这个 TableVC 的代码：

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

    let vc = bookTableViewController()

    vc.currentShelf = currentLibrary.allShelves[indexPath.row]

    navigationController?.pushViewController(vc, animated: true)


}

谢谢

Answer 1

这是因为你需要创建一个rightBarButtonItem，而不仅仅是设置标题。试试这个：

var barButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Add, target: self, action: @"addTapped:")
self.navigationItem.rightBarButtonItem = barButton