So i'm going to send data back and forth between 2 applications and i thought since it's A LOT of data in different models i can use a UIPasteboard. However i can't get it to work. Here's the code and issue.
struct TestModel {
var value1: Int = 0
var value2: String = "hi"
}
class ViewController: UIViewController {
#IBOutlet weak var redView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
let model = TestModel(value1: 1, value2: "hello")
let testModel = Mirror.init(reflecting: model)
guard let paste = UIPasteboard.init(name: UIPasteboard.Name(rawValue: "test1"), create: true) else {return}
let items = testModel.children.map({
return [$0.label ?? "noLabel": $0.value]
})
print(items)
paste.addItems(items)
print(paste.items[0]["value1"])
}
}
print(items) gives me the following:
[["value1": 1], ["value2": "hello"]]
So everything is working so far.
print(paste.items[0]["value1"]) however gives me:
<OS_dispatch_data: data[0x2835d3cc0] = { leaf, size = 43, buf = 0x102f18000 }>
And i have no clue how to unwrap this, i've tried unwrapping it to Int, String, Data, NSData and everything, but nothing seem to work.. so what is going on?
Related
This simple code:
func getProperties(object: AnyObject) -> [String] {
var result = [String]()
let mirror = Mirror(reflecting: object)
mirror.children.forEach { property in
guard let label = property.label else {
return
}
result.append(label)
}
return result
}
works for custom classes, e.g.:
class A {
var one: String
var two: Int
init() {
one = "hello"
two = 1
}
}
var a = A()
print(getProperties(object: a))
// prints ["one", "two"]
However the same code for UIFont (and other UIKit classes), returns nothing:
var font = UIFont.systemFont(ofSize: 10)
print(getProperties(object: font))
// prints []
I also tried an old-school extension for NSObject:
extension NSObject {
var propertyNames: [String] {
var result = [String]()
let clazz = type(of: self)
var count = UInt32()
guard let properties = class_copyPropertyList(clazz, &count) else {
return result
}
for i in 0..<Int(count) {
let property: objc_property_t = properties[i]
guard let name = NSString(utf8String: property_getName(property)) else {
continue
}
result.append(name as String)
}
return result
}
}
And again, it works for my custom classes (if they extend NSobject and the properties are marked as #objc):
class B: NSObject {
#objc var one: String
#objc var two: Int
override init() {
one = "hello"
two = 1
}
}
var b = B()
print(b.propertyNames)
// prints ["one", "two"]
but doesn't find any properties for UIFont.
If I look at the UIFont definition, the properties are seems defined like regular properties (or at least this is what Xcode shows:
open class UIFont : NSObject, NSCopying, NSSecureCoding {
//...
open var familyName: String { get }
open var fontName: String { get }
// etc
The type of the class is UICTFont though, not sure if it matters.
I would like to understand why this is not working, but my main question is more generic: is there any way to obtain the properties of the UIKit class (e.g. UIFont)?
I'm very new to programming.
I am trying to update an object in my Realm database but I get always an error.
I have tried to find the issue but I can't find anyone with a similar issue.
What I'm trying to do is:
I have a Game-Score-App.
It should display the names on Tab1 and on the Tab2 I want to give the user the ability, to change the names of the players. As soon as the ViewDidDisappear I want to write the changes to Realm.
I already figured out how to update the names in the database. And it works properly the first time.
But as soon as I go a second time on the Tab2 and go back to Tab1 again, I get the message "Primary key can't be changed after an object is inserted."
Any Ideas?
class Games: Object {
#objc dynamic var game_id = UUID().uuidString
#objc dynamic var gameName: String = ""
var playerNames = List<String>()
override class func primaryKey() -> String? {
return "game_id"
}
}
class FirstPageVC: UIViewController {
#IBOutlet var playerNameLabels: [UILabel]!
#IBOutlet weak var gameNameLabel: UILabel!
let realm = try! Realm()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
let games = realm.objects(Games.self)
gameNameLabel.text = games[0].gameName
for i in 0...playerNameLabels.count - 1 {
playerNameLabels[i].text = games[0].playerNames[i]
}
}
}
class SecondPageVC: UIViewController {
#IBOutlet var playerNameTextbox: [UITextField]!
#IBOutlet weak var gameNameTextbox: UITextField!
#IBOutlet weak var numberOfIndex: UITextField!
let realm = try! Realm()
var playerNames: [String] = []
var gameName: String = ""
var game = Games()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
if realm.objects(Games.self).count != 0 {
let games = realm.objects(Games.self)
gameNameTextbox.text = games[0].gameName
for i in 0...playerNameTextbox.count - 1 {
playerNameTextbox[i].text = games[0].playerNames[i]
}
}
}
#IBAction func addButton(_ sender: UIButton) {
gameName = gameNameTextbox.text!
for i in 0...playerNameTextbox.count - 1 {
playerNames.append(playerNameTextbox[i].text!)
}
let items = realm.objects(Games.self)
let number = Int(numberOfIndex.text!)
game.game_id = items[number!].game_id
game.gameName = gameName
game.playerNames.append(objectsIn: playerNames)
try! realm.write {
realm.add(game, update: .modified)
}
}
}
The problem is your Realm object structure. Anything that could possibly ever be changed should not be used as a primary key.
Also note from the Realm Documentation
Once an object with a primary key is added to a Realm, the primary key
cannot be changed.
To expand on that, it's often best practice to disassociate an objects key (e.g. primary key) from the rest of the properties of an object.
Here's how to do that
class Games: Object{
#objc dynamic var game_id = UUID().uuidString
#objc dynamic var gameName: String = ""
var playerNames = List<String>()
override class func primaryKey() -> String? {
return "game_id"
}
}
UUID().uuidString will generate a unique string for every object that's created and will look something like this string
CDEA69EA-AC84-4465-ABE3-DDA29D31B925
Once the object is created, you can use it to load that specific object or update it's properties.
See Objects with Primary Keys
Here's how to change the game name
let item = realm.object(ofType: Game.self, forPrimaryKey: "CDEA69EA-AC84-4465-ABE3-DDA29D31B925")!
try! realm.write {
game.gameName = "Pwn You!"
}
Try this solution:
Replace the code in viewDidDisappear after the end of for loop with the following code:
if let gameInRealm = realm.objects(Game.self).first{
try! realm.write {
gameInRealm.gameName = gameName
gameInRealm.playerNames = playerNames
}
}else{
game.gameName = gameName
game.playerNames.append(objectsIn: playerNames)
realm.add(game)
}
Explanation (if needed):
The code changes the existing Game properties in case a Game object exists. Otherwise, it creates a new one with the new properties.
Therefore, the else statement should get executed the first time you leave SecondPageVC, and then the if statement will get triggered every other time you leave SecondPageVC.
I'm new to RxSwift. This is quite tricky.
I'm creating like ToDoList that views which are tableView and add-item view are separated by TabBarController.
I have successfully displayed the list array and added a new item into tableView.
I also wanted to display the number of array's count and favourite count in the view that has tableView so that I have displayed it by throwing a value with .just.
But displaying a value based on the result of the array displayed by SearchBar, the value is not reflected as I expected.
In MainViewModel, I made sure if I could get the number of array's count properly by print, but apparently the value was fine.
It is just not reflected in the View.
// Model
struct Item: Codable {
var name = String()
var detail = String()
var tag = String()
var memo = String()
var fav = Bool()
var cellNo = Int()
init(name: String, detail: String, tag: String, memo: String, fav: Bool, celllNo: Int) {
self.name = name
self.detail = detail
self.tag = tag
self.memo = memo
self.fav = fav
self.cellNo = celllNo
}
init() {
self.init(
name: "Apple",
detail: "ringo",
tag: "noun",
memo: "",
fav: false,
celllNo: 0
)
}
}
struct SectionModel: Codable {
var list: [Item]
}
extension SectionModel: SectionModelType {
var items: [Item] {
return list
}
init(original: SectionModel, items: [Item]) {
self = original
self.list = items
}
}
Singleton share class
final class Sharing {
static let shared = Sharing()
var items: [Item] = [Item()]
var list: [SectionModel] = [SectionModel(list: [Item()])] {
didSet {
UserDefault.shared.saveList(list: list)
}
}
let listItems = BehaviorRelay<[SectionModel]>(value: [])
}
extension Sharing {
func calcFavCount(array: [Item]) -> Int {
var count = 0
if array.count > 0 {
for i in 0...array.count - 1 {
if array[i].fav {
count += 1
}
}
}
return count
}
}
// MainTabViewController
class MainTabViewController: UIViewController {
#IBOutlet weak var listTextField: UITextField!
#IBOutlet weak var tagTextField: UITextField!
#IBOutlet weak var itemCountLabel: UILabel!
#IBOutlet weak var favCountLabel: UILabel!
#IBOutlet weak var favIcon: UIImageView!
#IBOutlet weak var infoButton: UIButton!
#IBOutlet weak var searchBar: UISearchBar!
#IBOutlet weak var tableView: UITableView!
private lazy var viewModel = MainTabViewModel(
searchTextObservable: searchTextObservable
)
private let disposeBag = DisposeBag()
private var dataSource: RxTableViewSectionedReloadDataSource<SectionModel>!
override func viewDidLoad() {
super.viewDidLoad()
setupTableViewDataSource()
tableViewSetup()
listDetailSetup()
}
// create Observable searchBar.text to pass to ViewModel
var searchTextObservable: Observable<String> {
let debounceValue = 200
// observable to get the incremental search text
let incrementalTextObservable = rx
.methodInvoked(#selector(UISearchBarDelegate.searchBar(_:shouldChangeTextIn:replacementText:)))
.debounce(.milliseconds(debounceValue), scheduler: MainScheduler.instance)
.flatMap { [unowned self] _ in Observable.just(self.searchBar.text ?? "") }
// observable to get the text when the clear button or enter are tapped
let textObservable = searchBar.rx.text.orEmpty.asObservable()
// merge these two above
let searchTextObservable = Observable.merge(incrementalTextObservable, textObservable)
.skip(1)
.debounce(.milliseconds(debounceValue), scheduler: MainScheduler.instance)
.distinctUntilChanged()
return searchTextObservable
}
func setupTableViewDataSource() {
dataSource = RxTableViewSectionedReloadDataSource<SectionModel>(configureCell: {(_, tableView, indexPath, item) in
let cell = tableView.dequeueReusableCell(withIdentifier: "ListCell") as! ListCell
cell.selectionStyle = .none
cell.backgroundColor = .clear
cell.configure(item: item)
return cell
})
}
func tableViewSetup() {
tableView.rx.itemDeleted
.subscribe {
print("delete")
}
.disposed(by: disposeBag)
viewModel.dispItems.asObservable()
.bind(to: tableView.rx.items(dataSource: dataSource))
.disposed(by: disposeBag)
}
func listDetailSetup() {
viewModel.itemCountObservable
.bind(to: itemCountLabel.rx.text)
.disposed(by: disposeBag)
viewModel.favCountObservable
.bind(to: favCountLabel.rx.text)
.disposed(by: disposeBag)
}
}
MainTabViewModel
final class MainTabViewModel {
private let disposeBag = DisposeBag()
private let userDefault: UserDefaultManager
var dispItems = BehaviorRelay<[SectionModel]>(value: [])
private let shared = Sharing.shared
// lazy var itemCount = shared.list[0].list.count
// lazy var favCount = shared.calcFavCount
var itemCountObservable: Observable<String>
var favCountObservable: Observable<String>
init(searchTextObservable: Observable<String>,
userDefault: UserDefaultManager = UserDefault()) {
self.userDefault = userDefault
let initialValue = shared.list
shared.listItems.accept(initialValue)
dispItems = shared.listItems
// this part is to display the initil number -> success
var itemCount = shared.list[0].list.count
itemCountObservable = .just(itemCount.description + " items")
var favCount = shared.calcFavCount(array: shared.list[0].list)
favCountObservable = .just(favCount.description)
// this part is based on the searching result -> failure
searchTextObservable.subscribe(onNext: { text in
if text.isEmpty {
let initialValue = self.shared.list
self.shared.listItems.accept(initialValue)
self.dispItems = self.shared.listItems
}else{
let filteredItems: [Item] = self.shared.list[0].list.filter {
$0.name.contains(text)
}
let filteredList = [SectionModel(list: filteredItems)]
self.shared.listItems.accept(filteredList)
self.dispItems = self.shared.listItems
itemCount = filteredItems.count
self.itemCountObservable = .just(itemCount.description + " items")
favCount = self.shared.calcFavCount(array: filteredItems)
self.favCountObservable = .just(favCount.description)
print("\(itemCount) items") // the ideal number is in but not shown in the view
}
})
.disposed(by: disposeBag)
}
}
I removed unnecessary code but I mostly pasted a whole code for your understanding.
Hope you could help me.
Thank you.
I solved this issue anyway; the value was reflected.
the issue was that itemCountObservable was declared as observable and .just was used.
How .just works is to throw onNext once and it is completed, which means the change I did in searchTextObservable.subscribe(onNext~ is unacceptable.
So I shifted the itemCountObservable: Observable<String> to BehaviorRelay<String>that only onNext is thrown and not completed, then it works.
My understanding of this issue is that itemCountObservable: Observable<String> stopped throwing a value due to .just as I've written above.
Am I correct??
If you're familiar with the difference between Observable and BehaviorRelay, it would be appreciated if you could tell me.
Thanks.
Using Xcode-8.2.1, Swift-3.0.2, RealmSwift-2.2.0, iOS-Simulator-10:
I try applying the MVVM pattern (explained by Steve Scott here) using Realm.
Everything works until the moment (inside the VIEW-part - see below) where I try to access a viewmodel-property. It says: Realm accessed from incorrect thread
How could I still make the MVVM-pattern do its job of separating model, view-model and view but, on the same time, get thread-safety with realm ?
Is there a way to make Realm-results (i.e. Results<BalancesDataEntry>) being passed across threads ??
Here is my code:
(the issue happens at the very bottom, inside the View-part)
// REALM-OBJECT:
import Foundation
import RealmSwift
class BalancesDataEntry: Object {
dynamic var category: String = ""
dynamic var index: Int = 0
}
MODEL:
import Foundation
import RealmSwift
class MVVMCBalancesModel: BalancesModel
{
fileprivate var entries = [BalancesDataEntry]()
let realm = try! Realm()
init() {
self.createDataEntries()
}
fileprivate func createDataEntries() {
let myBalance = BalancesDataEntry()
myBalance.index = 0
myBalance.category = "Love"
try! self.realm.write {
self.realm.deleteAll()
self.realm.add(myBalance)
}
}
func getEntries(_ completionHandler: #escaping (_ entries: [BalancesDataEntry]) -> Void)
{
// Simulate Aysnchronous data access
DispatchQueue.global().async {
let realmThread = try! Realm()
let returnArray: [BalancesDataEntry] = Array(realmThread.objects(BalancesDataEntry.self))
completionHandler(returnArray)
}
}
}
VIEW-MODEL:
import Foundation
import RealmSwift
class MVVMCBalancesViewModel: BalancesViewModel
{
weak var viewDelegate: BalancesViewModelViewDelegate?
weak var coordinatorDelegate: BalancesViewModelCoordinatorDelegate?
fileprivate var entries: [BalancesDataEntry]? {
didSet {
viewDelegate?.entriesDidChange(viewModel: self)
}
}
var model: BalancesModel? {
didSet {
entries = nil;
model?.getEntries({ (myEntries) in
self.entries = myEntries
})
}
}
var title: String {
return "My Balances"
}
var numberOfEntries: Int {
if let entries = entries {
return entries.count
}
return 0
}
func entryAtIndex(_ index: Int) -> BalancesDataEntry?
{
if let entries = entries , entries.count > index {
return entries[index]
}
return nil
}
func useEntryAtIndex(_ index: Int)
{
if let entries = entries, let coordinatorDelegate = coordinatorDelegate , index < entries.count {
coordinatorDelegate.balancesViewModelDidSelectData(self, data: entries[index])
}
}
}
VIEW:
import UIKit
class MVVMCBalancesViewController: UIViewController {
#IBOutlet weak var label1Outlet: UILabel!
#IBOutlet weak var label2Outlet: UILabel!
var viewModel: BalancesViewModel? {
willSet {
viewModel?.viewDelegate = nil
}
didSet {
viewModel?.viewDelegate = self
refreshDisplay()
}
}
var isLoaded: Bool = false
func refreshDisplay()
{
if let viewModel = viewModel , isLoaded {
// !!!!!!! HERE IS THE ISSUE: Realm accessed from incorrect thread !!!!
self.label1Outlet.text = viewModel.entryAtIndex(0)?.category
self.label2Outlet.text = viewModel.entryAtIndex(1)?.category
} else {
}
}
override func viewDidLoad()
{
super.viewDidLoad()
isLoaded = true
refreshDisplay();
}
}
extension MVVMCBalancesViewController: BalancesViewModelViewDelegate
{
func entriesDidChange(viewModel: BalancesViewModel)
{
}
}
You can use ThreadSafeReference to pass Realm's thread-confined types (Object, Results, List, LinkingObjects) to a different thread. The documentation's section on Passing Instances Across Threads contains this example of passing a single instance of an Object subclass across threads:
let person = Person(name: "Jane")
try! realm.write {
realm.add(person)
}
let personRef = ThreadSafeReference(to: person)
DispatchQueue(label: "background").async {
let realm = try! Realm()
guard let person = realm.resolve(personRef) else {
return // person was deleted
}
try! realm.write {
person.name = "Jane Doe"
}
}
It can be used similarly for Results.
I have found a workaround (see below): Maybe you have better solutions - please let me know!
Here is my github-code realm_mvvm_c on github
After introducing a new protocol and making (pretty much everything) conform to it, things worked out.
Here is the protocol called DataEntry:
import Foundation
protocol DataEntry: class {
var idx: Int { get set }
var category: String { get set }
}
Now, make everything conform to it, such as
--> the realm object (i.e. class BalancesDataEntry: Object, DataEntry {...)
--> the getEntries return value (i.e. func getEntries(_ completionHandler: #escaping (_ entries: [DataEntry]) -> Void))
--> the View-Model's entries (i.e. fileprivate var entries: [DataEntry]? {..)
--> all the corresponding Model- and View-Model protocols also need the DataEntry datatype (see git-repo for complete picture)
After that, it was enough to change the completion-handler return-array of the MODEL's method getEntries(..) to a newly created object-instance (ie. DataEntryDub) that is keept conform to the DataEntry protocol:
func getEntries(_ completionHandler: #escaping (_ entries: [DataEntry]) -> Void)
{
// Simulate Aysnchronous data access
DispatchQueue.global().async {
let realmThread = try! Realm()
class DataEntryDub: DataEntry {
var idx: Int
var category: String
init(idx: Int, category: String) {
self.idx = idx
self.category = category
}
}
var returnArray = [DataEntry]()
for entry in realmThread.objects(BalancesDataEntry.self) {
returnArray.append(DataEntryDub(idx: entry.idx, category: entry.category))
}
completionHandler(returnArray)
}
}
Here is my github-code realm_mvvm_c on github
I would like to call a function which is coded on another class.
So far I have made a struct on the file structs.swift for my data:
struct defValues {
let defCityName: String
let loadImages: Bool
init(defCity: String, loadImgs: Bool){
self.defCityName = defCity
self.loadImages = loadImgs
}
}
I have made the file Defaults.swift containing:
import Foundation
class DefaultsSet {
let cityKey: String = "default_city"
let loadKey: String = "load_imgs"
func read() -> defValues {
let defaults = NSUserDefaults.standardUserDefaults()
if let name = defaults.stringForKey(cityKey){
print(name)
let valuesToReturn = defValues(defCity: name, loadImgs: true)
return valuesToReturn
}
else {
let valuesToReturn = defValues(defCity: "No default city set", loadImgs: true)
return valuesToReturn
}
}
func write(city: String, load: Bool){
let def = NSUserDefaults.standardUserDefaults()
def.setObject(city, forKey: cityKey)
def.setBool(load, forKey: loadKey)
}
}
in which I have the two functions read, write to read and write data with NSUsersDefault respectively.
On my main ViewController I can read data with:
let loadeddata: defValues = DefaultsSet().read()
if loadeddata.defCityName == "No default city set" {
defaultCity = "London"
}
else {
defaultCity = loadeddata.defCityName
defaultLoad = loadeddata.loadImages
}
But when I try to write data it gives me error. I use this code:
#IBOutlet var settingsTable: UITableView!
#IBOutlet var defaultCityName: UITextField!
#IBOutlet var loadImgs: UISwitch!
var switchState: Bool = true
#IBAction func switchChanged(sender: UISwitch) {
if sender.on{
switchState = true
print(switchState)
}else {
switchState = false
print(switchState)
}
}
#IBAction func saveSettings(sender: UIButton) {
DefaultsSet.write(defaultCityName.text, switchState)
}
You need an instance of the DefaultsSet class
In the view controller add this line on the class level
var setOfDefaults = DefaultsSet()
Then read
let loadeddata = setOfDefaults.read()
and write
setOfDefaults.write(defaultCityName.text, switchState)
The variable name setOfDefaults is on purpose to see the difference.
Or make the functions class functions and the variables static variables and call the functions on the class (without parentheses)
From the code you posted, it seems you either need to make the write method a class method (just prefix it with class) or you need to call it on an instance of DefaultsSet: DefaultsSet().write(defaultCityName.text, switchState).
Another issue I found is that you also need to unwrapp the value of the textField. Your write method takes as parameters a String and a Bool, but the value of defaultCityName.text is an optional, so String?. This results in a compiler error.
You can try something like this:
#IBAction func saveSettings(sender: UIButton) {
guard let text = defaultCityName.text else {
// the text is empty - nothing to save
return
}
DefaultsSet.write(text, switchState)
}
This code should now compile and let you call your method.
Let me know if it helped you solve the problem