Adding new items to the checklist

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What you’ll do in this section:

我们这一期要做什么

  • Add a navigation controller
  • 添加一个导航栏控制器
  • Put the Add button into the navigation bar
  • 把一个 添加按钮 放到导航栏上
  • Add a fake item to the list when you press the Add button
  • 当你点击 添加按钮 时添加一个假数据
  • Delete items with swipe-to-delete
  • 当 滑动删除 时删除事项
  • Open the Add Item screen that lets the user type the text for the item
  • 打开 添加事项 界面使用户可以输入事项

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Add a new action method to ChecklistViewController.swift:

@IBAction func addItem() {
}

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Let’s give addItem() something to do. Back in ChecklistViewController.swift, fill out the body of that method:

@IBAction func addItem() {
    // update Model
    let newRowIndex = items.count
    let item = ChecklistItem()
    item.text = "I am a new row"
    item.checked = false
    items.append(item)
    
    // update View
    let indexPath = NSIndexPath(forRow: newRowIndex, inSection: 0)
    let indexPaths = [indexPath] 
    tableView.insertRowsAtIndexPaths(indexPaths, withRowAnimation: .Automatic)
}

To recap, you 总结

  1. created a new ChecklistItem object 添加一个新的 ChecklistItem 对象
  2. added it to the data model, and 把它添加到 数据模型，并且
  3. inserted a new cell for it in the table view. 插入一个新行到 TableView。

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Deleting rows

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override func tableView(tableView: UITableView,
commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
    // 1
    items.removeAtIndex(indexPath.row)
    // 2
    let indexPaths = [indexPath] tableView.deleteRowsAtIndexPaths(indexPaths,
}
  1. remove the item from the data model, and 从 数据模型 中删除一项，并且
  2. delete the corresponding row from the table view. 从 TableView 中删除与之相符的一行。