UITableView编辑模式不显示删除按钮

Question

I'm replicating the sample Food Tracker app from apple and have an issue where the items from my TableView in Edit mode don't show the left hand delete icon (the round red one). If I swipe left I get a delete button on the right. I've downloaded the Food Tracker code and it works.

The difference I can see is that the sample app has implemented a UITableViewController, whereas I have a UITableView within a standard UIViewController. I'm not sure why this doesn't work.

There are some similar questions but they are older versions of Swift / Ios, so I'm not sure they are still relevant.

Here is the link to the sample app https://developer.apple.com/library/content/referencelibrary/GettingStarted/DevelopiOSAppsSwift/index.html#//apple_ref/doc/uid/TP40015214-CH2-SW1

Here are the funcs I recently added that should make it work

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {

    return true
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

    if editingStyle == .delete {
    //delete the row from the dataSource
        dataSource.remove(at: indexPath.row)
        tableView.deleteRows(at: [indexPath], with: .fade)

    }
    else if editingStyle == .insert {
    //create a new instance and insert the row

    }

}

And I added this to the ViewDidLoad() to get the Edit button in the Nav bar

 navigationItem.leftBarButtonItem = editButtonItem

Here's what the Food Tracker example looks like;

enter image description here

and mine is missing the left hand button. The only difference I can see is that I'm using a TableView inside a ViewController.

Thanks

Nick

Answer 1

I think I solved this. Effectively there's a fair bit of 'magic' that a UITableViewController is doing. To recreate this in a normal UIViewController with a TableView you have to override the SetEditing function and based on the title of the button put it in edit mode.

override func setEditing(_ editing: Bool, animated: Bool) {


    let status = navigationItem.leftBarButtonItem?.title



    if status == "Edit" {

        tableView.isEditing = true

        navigationItem.leftBarButtonItem?.title = "Done"

        }

    else {

        tableView.isEditing = false

        navigationItem.leftBarButtonItem?.title = "Edit"

    }

}

Answer 2

No need to check the title of the barButtonItem as tapping it already toggles its state and passes the correct state in editing param.

Also, when overriding, you need to invoke super's implementation as absence would always show the delete indicator.

override func setEditing(_ editing: Bool, animated: Bool) {
    super.setEditing(editing, animated: true)
    tableView.setEditing(editing, animated: true)
}