我正在创建一个潜水日志应用。当有人选择新潜水时，他们会收到两个选项的警报：“空白模板”或“将上次潜水用作模板”。 问题在于后期，最后一次潜水作为模板。
每次潜水我都会将数据记录到NSUserDefaults。因此，当有人想要最后一次潜水作为模板时，我只需调用每个默认值并填充表格视图。
但是，我在第一个字段，即diveSiteTextfield.text上收到一个nil错误，这让我很困惑：
以下是将数据保存到NSUserDefaults
的位置如您所见，我添加了一个打印命令来测试潜水点字段是否为零，但它显示的是正确的数据。 diveSiteTextfield.text不是零。
import UIKit
import Parse
var diveUUID = NSUUID().UUIDString
class DiveDetails1VC: UIViewController, UITextFieldDelegate, UITableViewDelegate, UIPickerViewDelegate, UIPickerViewDataSource
{
let userDefault = NSUserDefaults.standardUserDefaults()
@IBOutlet weak var ratingControl: DiveSiteRating!
@IBOutlet weak var diveSiteTextfield: UITextField!
@IBOutlet weak var diveDurationTextfield: UITextField!
...
func toDive2NewParse () {
let diveObject = PFObject(className: "divelog")
diveObject["diveNumber"] = diveNumberInt
diveObject["diveSite"] = diveSiteTextfield.text
diveObject["diveDuration"] = diveDurationTextfield.text
diveObject["maxDepth"] = diveMaxDepthTextfield.text
diveObject["diveDate"] = diveDateTextfield.text
diveObject["diveTime"] = diveTimeTextfield.text
diveObject["bodyOfWater"] = diveBodyOfWaterTextfield.text
diveObject["diveBuddy"] = diveBuddyTextfield.text
diveObject["diveCity"] = diveCityTextfield.text
diveObject["maxDepthSymbol"] = diveMaxDepthSymbolTextField.text
diveObject["diveCountry"] = diveCountryTextField.text
diveObject["uuid"] = "\(diveUUID)"
// diveObject["diveRating"] = ratingControl
diveObject["entryFrom"] = "Divelog"
if PFUser.currentUser()!.username == nil {
diveObject["username"] = "Not Signed in"
} else {
diveObject["username"] = PFUser.currentUser()!.username
}
diveObject.saveEventually()
userDefault.setObject(diveNumberInt, forKey: "diveNumber")
userDefault.setObject(diveSiteTextfield.text, forKey: "diveSite")
userDefault.setObject(diveDurationTextfield.text!, forKey: "diveDuration")
userDefault.setObject(diveMaxDepthTextfield.text, forKey: "diveDepth")
userDefault.setObject(diveMaxDepthSymbolTextField.text, forKey: "symbol_maxDepth")
userDefault.setObject(diveDateTextfield.text, forKey: "entryDate")
userDefault.setObject(diveTimeTextfield.text, forKey: "entryTime")
userDefault.setObject(diveCityTextfield.text, forKey: "diveCity")
userDefault.setObject(diveCountryTextField.text, forKey: "diveCountry")
userDefault.setObject(diveBodyOfWaterTextfield.text, forKey: "bodyOfWater")
userDefault.setObject(diveBuddyTextfield.text, forKey: "diveBuddy")
userDefault.setObject(diveUUID, forKey: "uuid")
userDefault.synchronize()
print("DiveSite is ...\(userDefault.objectForKey("diveSite"))")
}
以下是检索“最后一次潜水”的UIAlertAction：
@IBAction func addNewDive (sender: AnyObject) {
let alertController = UIAlertController(title: "New Dive", message: "Choose a template", preferredStyle:UIAlertControllerStyle.ActionSheet)
let buttonOne = UIAlertAction(title: "Blank template", style: .Default, handler: { (action) -> Void in
self.performSegueWithIdentifier("segueNewDive1", sender: self)
print("Button One Pressed")
})
let buttonTwo = UIAlertAction(title: "Use last dive as template", style: .Default, handler: { (action) -> Void in
self.VC1.diveSiteTextfield.text = self.userDefault.stringForKey("diveSite")
self.VC1.diveDurationTextfield.text = self.userDefault.stringForKey("diveDuration")
self.VC1.diveMaxDepthTextfield.text = self.userDefault.stringForKey("diveDepth")
...
self.DNo.textView.text = self.userDefault.objectForKey("diveNotes") as? String;
self.userDefault.synchronize()
self.performSegueWithIdentifier("segueNewDive1", sender: self)
任何帮助，了解为什么会非常感谢nil。
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