我有一个写作应用程序，用户可以创建一个可以添加到表格视图（和Firebase）中的帖子。 当我要保存新帖子时，应用程序崩溃。它永远不会访问if，它总是转到else，所以我认为if是不正确的。 我怎么知道if中userdefault中“ forKey”的键名是什么？
func readFromNSUserDefault()-> Memory?
{
let d : UserDefaults = UserDefaults.standard
if UserDefaults.standard.array(forKey: "") != nil
{
print("exists")
let strTitle = d.object(forKey: "title") as? String
let strBody = d.object(forKey: "body") as? String
let strImageRef = d.object(forKey: "imageRef") as? String
let uid = d.object(forKey: "uid") as? String
let imageData = d.object(forKey: "imageData") as? Data
let key = d.object(forKey: "key") as? String
let date = d.object(forKey: "date") as? NSNumber
let m = Memory(title: strTitle!, body: strBody!, key: key!, uid: uid!, imageRef: strImageRef!, date: date!) // A variable from type memory
m.image = UIImage(data: imageData!)
m.key = key!
return m
}
print ("doesn't exist")
let m : Memory?
m = nil
return m
}
保存功能：
@IBAction func saveMemorey(_ sender: UIButton) {
let d = UserDefaults.standard
if( mode == "newMemory")
{
self.addNewMemory()
d.set(true, forKey: "userAdded")
}
else if mode == "edit"
{
self.editNewMemory()
d.set(true, forKey: "userEdited")
}
d.synchronize()
self.navigationController?.popViewController(animated: true) // Returns to the memories page after clicking 'save'
}
func addNewMemory()
{
let refposts = ref.child("MEmories").childByAutoId()
dateToSet = Double(self.future.millisecondsSince1970)
imgref = "\(txtTitle.text!).png"
self.m = Memory(title: txtTitle.text!, body: tBody.text!, key: "", uid: (Auth.auth().currentUser!.uid), imageRef: imgref!, date: self.dateToSet as NSNumber)
refposts.setValue(m.toAnyObject(), withCompletionBlock: {(error,data) in
self.m.key = data.key!
self.m.image = self.ivImage.image
self.saveImage()
self.saveToNSUserDefaualts(memory: self.m)
})
}
func saveToNSUserDefaualts(memory:Memory)
{
let d : UserDefaults = UserDefaults.standard
d.set(memory.title, forKey: "title")
d.set(memory.body, forKey: "body")
d.set(memory.key, forKey: "key")
d.set(memory.imageRef, forKey: "imageRef")
d.set(memory.uid, forKey: "uid")
d.set(memory.key, forKey: "key")
d.set(memory.date, forKey: "date")
let imageData = NSData(data:ivImage.image!.pngData()!)
d.set(imageData, forKey: "imageData")
d.synchronize()
}
加载功能：
func loadMemories()
{
let UID = Auth.auth().currentUser!.uid
self.ref.child("MEmories").queryOrdered(byChild: "uid").queryEqual(toValue: UID).observeSingleEvent(of: .value, with: {
snapShot in
if let dict = snapShot.value as? NSDictionary
{
for d in (dict as? Dictionary<String,AnyObject>)!
{
let title = d.value["title"] as?String
let body = d.value["body"] as? String
let uid = d.value["uid"] as? String
let imageRef = d.value["imageRef"] as? String
let date = d.value["date"] as? NSNumber
let m = Memory(title: title!, body: body!, uid: uid!,imageRef:imageRef!, date: date!)
m.key = d.key
let tempImageRef = self.sref.child(m.imageRef)
tempImageRef.getData(maxSize: 500*1024*1024, completion: {(data,error) in
if error == nil
{
if let imageData = data
{
m.image = UIImage(data: imageData)
self.memories.append(m)
self.tbl.reloadData()
}
}
})
}
}//end of if
})
}
内存类别：
import Foundation
import Firebase
class Memory
{
// Class Attributes
var title : String
var uid : String // user id
var body : String
var key : String
var imageRef : String!
var image : UIImage?
var date : NSNumber
init( title:String , body:String , key:String = "", uid:String , imageRef:String , date:NSNumber ) // Build function
{
self.title = title
self.key = key
self.body = body
self.uid = uid
self.imageRef = imageRef
self.key = ""
self.date = date
}
func toAnyObject()-> [String:AnyObject]
{
return ["title" : self.title as AnyObject,"body":self.body as AnyObject,"uid":self.uid as AnyObject,"imageRef":self.imageRef as AnyObject,"date":self.date as AnyObject
]
}
}