【发布时间】：2016-07-19 16:03:23
【问题描述】：
我有显示项目列表的表格视图。每选中一行，就加一个勾号，对应的金额加到var total.
如果选择了另一行，则删除前一行的复选标记，减去前一行的金额。
我正在尝试在 NSUserdefaults 中保存和检索以下信息：
选中行的复选标记（如果选择了任何行），
var total 的值，
indexPathForCellSelected,
, 所选特定行的金额。
import UIKit
class EighthViewController: UIViewController, UITableViewDelegate,UITableViewDataSource {
struct Item {
var name:String // name of the row
var selected:Bool // whether is selected or not
var amount: Int // value of the item
}
var frequency = [
Item(name:"Every week",selected: false, amount: 30),
Item(name:"Every 2 weeks",selected: false, amount: 30),
Item(name:"Every 4 weeks",selected: false, amount: 30),
Item(name:"Once",selected: false, amount: 40),
Item(name:"End of tenancy cleaning", selected: false, amount: 44)
]
var total = 0
var indexPathForCellSelected: NSIndexPath?
@IBOutlet weak var tableView: UITableView!
let indexKey = "indexPathForCellSelected"
let totalKey = "total"
let amountKey = "amount"
override func viewDidLoad() {
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
// retrieve indexPathForCellSelected from NSUserDefaults
if let retrievedIndexPath = NSUserDefaults.standardUserDefaults().objectForKey(indexKey) {
let data1 = NSUserDefaults.standardUserDefaults().objectForKey(indexKey) as? NSData
indexPathForCellSelected = NSKeyedUnarchiver.unarchiveObjectWithData(data1!) as? NSIndexPath
// retrieve total from NSUserDefaults
if let totalRetrieved = NSUserDefaults.standardUserDefaults().objectForKey(totalKey) as? Int {
total = totalRetrieved
print(total)
}
//
if let itemAmount = NSUserDefaults.standardUserDefaults().objectForKey(amountKey) as? Int {
let myIndexpath = indexPathForCellSelected?.row
frequency[myIndexpath!].amount = itemAmount
**UPDATED:** tableView.cellForRowAtIndexPath(indexPathForCellSelected!)?.accessoryType = .Checkmark
}
}
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return frequency.count
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
// configure the cell
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath)
-> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell")
cell?.textLabel?.text = frequency[indexPath.row].name
return cell!
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
if !frequency[indexPath.row].selected {
// this avoid set initial value for the first time
if let index = indexPathForCellSelected {
// clear the previous cell
frequency[index.row].selected = false
tableView.cellForRowAtIndexPath(index)?.accessoryType = .None
self.total -= frequency[index.row].amount
print(total)
}
// mark the new one
frequency[indexPath.row].selected = true
tableView.cellForRowAtIndexPath(indexPath)?.accessoryType = .Checkmark
indexPathForCellSelected = indexPath
self.total += frequency[indexPath.row].amount
print(total)
if indexPathForCellSelected != nil { // check if there is a selected row in the table
//save indexPathForCellSelected in NSUserDefaults
let data = NSKeyedArchiver.archivedDataWithRootObject(indexPathForCellSelected!)
NSUserDefaults.standardUserDefaults().setObject(data, forKey: indexKey)
//save total in NSUserDefaults
NSUserDefaults.standardUserDefaults().setObject(total, forKey: totalKey)
// save amount in NSUserDefaults
NSUserDefaults.standardUserDefaults().setObject(frequency[indexPath.row].amount, forKey: amountKey)
} // end of if indexPathForCellSelected
}
}
}
这是应用程序的屏幕截图：link
【问题讨论】：
-
@Victor Sigler。你能看看上面的代码吗？
-
有什么问题？
-
@tommybananas 当我选择一行而不是添加与所选行对应的金额时，它会减去金额。
-
为什么这么复杂？只保存索引（行）要容易得多。它只是一个整数并且符合属性列表。
-
我的意思是，不要保存整个索引路径，只保存
indexPath.row然后你就不需要归档/取消归档的舞蹈。您可以使用 (NSUserDefaults.standardUserDefaults().integerForKey / setInteger: forKey:..) 轻松保存整数
标签： arrays swift uitableview nsuserdefaults