I am working on an app that uses an API that have some inconsistencies, I have achieved a result with these 2 observables that perform some shared actions but the first one 'servers' is an array that binds to the UITableView.
serversViewModel.servers
.asObservable()
.observeOn(MainScheduler.instance)
.bind(to: serversTableView.rx.items(cellIdentifier: ServersTableViewCell.identifier, cellType: ServersTableViewCell.self)) { [weak self] (row, element, cell) in
guard let strongSelf = self else { return }
cell.serverProxy.accept(element)
if let currentServer = strongSelf.serversViewModel.currentServer.value,
element == currentServer,
let index = strongSelf.serversViewModel.servers.value.firstIndex(where: { $0 == currentServer }){
strongSelf.serversTableView.selectRow(at: IndexPath(row: index, section: 0), animated: true, scrollPosition: .top)
}
}
.disposed(by: disposeBag)
serversViewModel.currentServer
.asObservable()
.observeOn(MainScheduler.instance)
.subscribe(onNext: { [weak self] (server) in
guard let strongSelf = self else { return }
if let server = server, let index = strongSelf.serversViewModel.servers.value.firstIndex(where: { $0 == server }){
strongSelf.serversTableView.selectRow(at: IndexPath(row: index, section: 0), animated: true, scrollPosition: .top)
}
else{
strongSelf.serversTableView.deselectAllItems(animated: false)
}
})
.disposed(by: disposeBag)
Is it possible to create a combined observable for both and use it for binding the UITableView?
Thank you
You want to use combineLatest. Note that most of this should actually be in your view model...
In the below code, the servers constant is a tuple of both the array of Server objects that should be displayed and the index path of the current server. Whenever either emits a new value, servers will emit a value.
You might find the following article helpful in the future: Recipes for Combining Observables in RxSwift
let servers = Observable.combineLatest(serversViewModel.servers, serversViewModel.currentServer) { (servers, server) -> ([Server], IndexPath?) in
let indexPath = server.flatMap { servers.firstIndex(of: $0) }
.map { IndexPath(row: $0, section: 0) }
return (servers, indexPath)
}
servers
.map { $0.0 }
.bind(to: serversTableView.rx.items(cellIdentifier: ServersTableViewCell.identifier, cellType: ServersTableViewCell.self)) { (row, element, cell) in
cell.serverProxy.accept(element)
}
.disposed(by: disposeBag)
servers
.map { $0.1 }
.bind(onNext: { [serversTableView] indexPath in
if let indexPath = indexPath {
serversTableView.selectRow(at: indexPath, animated: true, scrollPosition: .top)
}
else {
serversTableView.deselectAllItems(animated: false)
}
})
.disposed(by: disposeBag)
I'd approach from a slightly different way. First I would consider pulling the combine observable back into the ViewModel you have already structured. No need for this composition to be in your ViewController.
Then output that composed signal to bind into your rx.items.
You can wrap your objects will a table cell view model to control whether to show them in a 'selected state'
Then also output the currentServer from your viewModel to simply scroll to it.
There are several ways to combine observables in RxSwift. For your specific case, you will have to choose one that suits your needs best. Some of the operators are:
combineLatest
zip
merge
etc.
Read this documentation to get more idea about what each one it does.
Related
As a follow up on #Asperi's answer of my question on how to drag and drop contacts and, I'd also like to be able to drag and drop email in the same way. Here is my code:
import SwiftUI
import UniformTypeIdentifiers
let uttypes = [String(kUTTypeEmailMessage)]
struct ContentView: View
{
let dropDelegate = EmailDropDelegate()
var body: some View
{
VStack
{
Text("Drag your email here!")
.padding(20)
}
.onDrop(of: uttypes, delegate: dropDelegate)
}
}
struct EmailDropDelegate: DropDelegate
{
func validateDrop(info: DropInfo) -> Bool
{
return true
}
func dropEntered(info: DropInfo)
{
print ("Drop Entered")
}
func performDrop(info: DropInfo) -> Bool
{
let items = info.itemProviders(for: uttypes)
for item in items
{
print (item.registeredTypeIdentifiers) // prints []
item.loadDataRepresentation(forTypeIdentifier: kUTTypeEmailMessage as String, completionHandler: { (data, error) in
if let data = data
{
print(data)
}
})
}
return true
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I'm not getting any data back that I can decode.
2020-11-08 09:34:54.877532+0000 DropContact[3856:124769] Cannot find representation conforming to type public.email-message
This feature has been eluding me forever so any help would be very much appreciated.
Well... the approach is the same, the only thing is that Apple Mail does not provide kUTTypeEmailMessage UTI representation on drag (copy)
If we register self for generic kUTTypeContent UTI and investigate content of pasteboard on drop mail from Mail, we get:
Ie, here is a complete list of representations:
com.apple.mail.PasteboardTypeMessageTransfer,
com.apple.mail.PasteboardTypeAutomator,
com.apple.pasteboard.promised-file-url,
dyn.ah62d4rv4gu8y6y4usm1044pxqzb085xyqz1hk64uqm10c6xenv61a3k,
NSPromiseContentsPboardType,
com.apple.pasteboard.promised-file-content-type,
dyn.ah62d4rv4gu8yc6durvwwa3xmrvw1gkdusm1044pxqyuha2pxsvw0e55bsmwca7d3sbwu,
Apple files promise pasteboard type,
public.url,
CorePasteboardFlavorType 0x75726C20,
dyn.ah62d4rv4gu8yc6durvwwaznwmuuha2pxsvw0e55bsmwca7d3sbwu,
Apple URL pasteboard type,
public.url-name,
CorePasteboardFlavorType 0x75726C6E,
public.utf8-plain-text,
NSStringPboardType
so now you can load data of any of those types from above (except of course Apple's own privates). And, by the way, that list might (and rather will) depend on macOS version.
I have no solution for this but might be on a path to it.
As I mentioned in a comment, it looks to me that SwiftUI does not have a way to fulfil file promises yet.
Afaik Mail, Photos and Safari using file promises while dragging images or mails.
This might help some one else with a solution.
func performDrop(info: DropInfo) -> Bool {
let pasteboard = NSPasteboard(name: .drag)
guard let items = pasteboard.pasteboardItems else { return false }
// it returns the content of the public.url → is an encoded message url
print(pasteboard.readObjects(forClasses: [NSURL.self]))
// getting available types for pasteboard
let types = NSFilePromiseReceiver.readableDraggedTypes.map { NSPasteboard.PasteboardType($0) }
for type in types {
for item in items {
print("type:", type)
print(item.data(forType: type))
}
}
}
This prints this:
Optional([message:%3Cf6304df5.BAAAA6Ge1-UAAAAAAAAAALTyTrMAAVNI2qYAAAAAAAcXzQBjqtkK#mailjet.com%3E])
type: NSPasteboardType(_rawValue: com.apple.NSFilePromiseItemMetaData)
nil
type: NSPasteboardType(_rawValue: dyn.ah62d4rv4gu8yc6durvwwa3xmrvw1gkdusm1044pxqyuha2pxsvw0e55bsmwca7d3sbwu)
nil
type: NSPasteboardType(_rawValue: com.apple.pasteboard.promised-file-content-type)
Optional(20 bytes)
But I don't know what data type com.apple.pasteboard.promised-file-content-type is … Maybe some kind of NSFilePromiseReceiver.
Maybe this helps someone.
Edit
Tried something else, maybe something more promising.
func performDrop(info: DropInfo) -> Bool {
let pasteboard = NSPasteboard(name: .drag)
guard let filePromises = pasteboard.readObjects(forClasses: [NSFilePromiseReceiver.self], options: nil) else { return false }
guard let receiver = filePromises.first as? NSFilePromiseReceiver else { return false }
let queue = OperationQueue.main
receiver.receivePromisedFiles(atDestination: URL.temporaryDirectory, operationQueue: queue) { (url, error) in
print(url, error)
}
}
In this example I'm able to get the NSFilePromiseReceiver but something is off.
After around 20 to 30s the callback is called and I get the URL finally – so there is maybe some potential to improve. I think it has something todo with the Queue.
Edit
I was able to move/copy the dropped mail into the download folder.
func performDrop(info: DropInfo) -> Bool {
let pasteboard = NSPasteboard(name: .drag)
guard let filePromises = pasteboard.readObjects(forClasses: [NSFilePromiseReceiver.self], options: nil) else { return false }
guard let receiver = filePromises.first as? NSFilePromiseReceiver else { return false }
let dispatchGroup = DispatchGroup()
let queue = OperationQueue()
let destUrl = URL.downloadsDirectory
dispatchGroup.enter()
var urls: [URL] = []
receiver.receivePromisedFiles(atDestination: destUrl, operationQueue: queue) { (url, error) in
if let error = error {
print(error)
} else {
urls.append(url)
}
print(receiver.fileNames, receiver.fileTypes)
dispatchGroup.leave()
}
dispatchGroup.notify(queue: .main, execute: {
print(urls)
})
}
I ran into a situation where I would fetch an API which will generate json data of registered users. I would then have to loop through each user and fetch their avatar from remote url and save it to disk. I can perform this second task inside subscribe but this is not a best practice. I am trying to implement it with map, flatMap etc.
Here is my sample code:
self.dataManager.getUsers()
.observeOn(MainScheduler.instance)
.subscribeOn(globalScheduler)
.map{ [unowned self] (data) -> Users in
var users = data
// other code for manipulating users goes here
// then below I am trying to use another loop to fetch their avatars
if let cats = users.categories {
for cat in cats {
if let profiles = cat.profiles {
for profile in profiles {
if let thumbnail = profile.thumbnail,
let url = URL(string: thumbnail) {
URLSession.shared.rx.response(request: URLRequest(url: url))
.subscribeOn(MainScheduler.instance)
.subscribe(onNext: { response in
// Update Image
if let img = UIImage(data: response.data) {
try? Disk.save(img, to: .caches, as: url.lastPathComponent)
}
}, onError: { (error) in
}).disposed(by: self.disposeBag)
}
}
}
}
}
return users
}
.subscribe(onSuccess: { [weak self] (users) in
}).disposed(by: disposeBag)
There are 2 problems in this code. First is with the rx on URLSession which execute the task in background on another thread and there is no way to acknowledge the main subscribe back when this operation will finish. Second is with the loop and rx which is not efficient as it should generate multiple observables and then process it.
Any idea to improve this logic is welcome.
This was a fun puzzle.
The "special sauce" that solves the problem is in this line:
.flatMap {
Observable.combineLatest($0.map {
Observable.combineLatest(
Observable.just($0.0),
URLSession.shared.rx.data(request: $0.1)
.materialize()
)
})
}
The map before the line creates an Observable<[(URL, URLRequest)]> and the line in question converts it to an Observable<[(URL, Event<Data>)]>.
The line does this by:
Set up the network call to create an Observable<Data>
Materialize it to create an Observable<Event<Data>> (this is done so an error in one download won't shutdown the entire stream.)
Lift the URL back into an Observable which gives us an Observable<URL>
Combine the observables from steps 2 & 3 to produce an Observable<(URL, Event<Data>)>.
Map each array element to produce [Observable<(URL, Event<Data>)>]
Combine the observables in that array to finally produce Observable<[(URL, Event<Data>)]>
Here is the code
// manipulatedUsers is for the code you commented out.
// users: Observable<Users>
let users = self.dataManager.getUsers()
.map(manipulatedUsers) // manipulatedUsers(_ users: Users) -> Users
.asObservable()
.share(replay: 1)
// this chain is for handling the users object. You left it blank in your code so I did too.
users
.observeOn(MainScheduler.instance)
.subscribe(onNext: { users in
})
.disposed(by: disposeBag)
// This navigates through the users structure and downloads the images.
// images: Observable<(URL, Event<Data>)>
let images = users.map { $0.categories ?? [] }
.map { $0.flatMap { $0.profiles ?? [] } }
.map { $0.compactMap { $0.thumbnail } }
.map { $0.compactMap { URL(string: $0) } }
.map { $0.map { ($0, URLRequest(url: $0)) } }
.flatMap {
Observable.combineLatest($0.map {
Observable.combineLatest(
Observable.just($0.0),
URLSession.shared.rx.data(request: $0.1)
.materialize()
)
})
}
.flatMap { Observable.from($0) }
.share(replay: 1)
// this chain filters out the errors and saves the successful downloads.
images
.filter { $0.1.element != nil }
.map { ($0.0, $0.1.element!) }
.map { ($0.0, UIImage(data: $0.1)!) }
.observeOn(MainScheduler.instance)
.bind(onNext: { url, image in
try? Disk.save(image, to: .caches, as: url.lastPathComponent)
return // need two lines here because this needs to return Void, not Void?
})
.disposed(by: disposeBag)
// this chain handles the download errors if you want to.
images
.filter { $0.1.error != nil }
.bind(onNext: { url, error in
print("failed to download \(url) because of \(error)")
})
.disposed(by: disposeBag)
I have a UICollectionView bound to an array of entities using BehaviorSubject and all is fine, data is loaded from the network and displayed correctly.
The problem is, based on user action, I'd like to change the CellType used by the UICollectionView and force the collection to re-create all cells, how do I do that?
My bind code looks like:
self.dataSource.bind(to: self.collectionView!.rx.items) {
view, row, data in
let indexPath = IndexPath(row: row, section: 0)
var ret: UICollectionViewCell? = nil
if (self.currentReuseIdentifier == reuseIdentifierA) {
// Dequeue cell type A and bind it to model
ret = cell
} else {
// Dequeue cell type B and bind it to model
ret = cell
}
return ret!
}.disposed(by: disposeBag)
The general way to solve problems in Rx is to think of what you want the output effect to be and what input effects can affect it.
In your case, the output effect is the display of the table view. You have identified two input effects "data is loaded from the network" and "user action". In order to make your observable chain work properly, you will have to combine your two input effects in some way to get the behavior you want. I can't say how that combination should take place without more information, but here is an article explaining most of the combining operators available: https://medium.com/#danielt1263/recipes-for-combining-observables-in-rxswift-ec4f8157265f
As a workaround, you can emit an empty list then an actual data to force the collectionView to reload like so:
dataSource.onNext([])
dataSource.onNext([1,2,3])
I think you can use different data type to create cell
import Foundation
import RxDataSources
enum SettingsSection {
case setting(title: String, items: [SettingsSectionItem])
}
enum SettingsSectionItem {
case bannerItem(viewModel: SettingSwitchCellViewModel)
case nightModeItem(viewModel: SettingSwitchCellViewModel)
case themeItem(viewModel: SettingCellViewModel)
case languageItem(viewModel: SettingCellViewModel)
case contactsItem(viewModel: SettingCellViewModel)
case removeCacheItem(viewModel: SettingCellViewModel)
case acknowledgementsItem(viewModel: SettingCellViewModel)
case whatsNewItem(viewModel: SettingCellViewModel)
case logoutItem(viewModel: SettingCellViewModel)
}
extension SettingsSection: SectionModelType {
typealias Item = SettingsSectionItem
var title: String {
switch self {
case .setting(let title, _): return title
}
}
var items: [SettingsSectionItem] {
switch self {
case .setting(_, let items): return items.map {$0}
}
}
init(original: SettingsSection, items: [Item]) {
switch original {
case .setting(let title, let items): self = .setting(title: title, items: items)
}
}
}
let dataSource = RxTableViewSectionedReloadDataSource<SettingsSection>(configureCell: { dataSource, tableView, indexPath, item in
switch item {
case .bannerItem(let viewModel),
.nightModeItem(let viewModel):
let cell = (tableView.dequeueReusableCell(withIdentifier: switchReuseIdentifier, for: indexPath) as? SettingSwitchCell)!
cell.bind(to: viewModel)
return cell
case .themeItem(let viewModel),
.languageItem(let viewModel),
.contactsItem(let viewModel),
.removeCacheItem(let viewModel),
.acknowledgementsItem(let viewModel),
.whatsNewItem(let viewModel),
.logoutItem(let viewModel):
let cell = (tableView.dequeueReusableCell(withIdentifier: reuseIdentifier, for: indexPath) as? SettingCell)!
cell.bind(to: viewModel)
return cell
}
}, titleForHeaderInSection: { dataSource, index in
let section = dataSource[index]
return section.title
})
output.items.asObservable()
.bind(to: tableView.rx.items(dataSource: dataSource))
.disposed(by: rx.disposeBag)
RxDataSources
swiftHub
I'm a beginner to cocoa and I've been trying to make a simple app for Mac using swift programming language, but I'm stuck and can't find a solution.
I want to present a data from dictionary in two or more tableViews, where the first table will show key, and the second table will show value.
For example, I have a dictionary
var worldDict:NSDictionary = ["Africa":["Egypt", "Togo"],"Europe": ["Austria", "Spain"]]
I can present all continents in the first table, but I can't find out how to make second table to display countries from continent I choose in the first table.
My ViewController is a DataSource and Delegate for both tables.
extension ViewController: NSTableViewDataSource {
func numberOfRowsInTableView(tableView: NSTableView) -> Int {
if tableView == continentTable {
return self.worldDict.valueForKey("Continent")!.count
} else if tableView == countryTable {
return self.worldDict.valueForKey("Continent")!.allKeys.count
}
return 0
}
func tableView(tableView: NSTableView, viewForTableColumn tableColumn: NSTableColumn?, row: Int) -> NSView? {
var cell = tableView.makeViewWithIdentifier(tableColumn!.identifier, owner: self) as! NSTableCellView
if tableView == self.continentTable {
let continent: AnyObject? = wordlDict.valueForKey("Continent")
var keys = continent!.allKeys
cell.textField?.stringValue = keys[row] as! String
} else if tableView == self.countryTable {
var countriesOfContinent: AnyObject? = worldDict.valueForKey("Continent")?.valueForKey("Africa")!
cell.textField?.stringValue = countriesOfContinent?.allKeys[row] as! String
}
return cell
}
}
Here I present data from dictionary in tables, but separately, and can't figure out how to make them work together.
Also I know how to get the number of row that has been selected
extension ViewController: NSTableViewDelegate {
func tableViewSelectionDidChange(notification: NSNotification) {
let continentSelected = rowSelected()
}}
func rowSelected() -> Int? {
let selectedRow = self.continentTable.selectedRow
if selectedRow >= 0 && selectedRow < self.worldDict.valueForKey("Continent")!.count {
return selectedRow
}
return nil
}
Part of the problem is that you're relying on the ordering of the keys returned by allKeys() to be reliable, which it's not. You need to keep a separate array of continents. It can basically be a copy of whatever allKeys() returned on one occasion, but you should not keep calling allKeys() each time.
In numberOfRowsInTableView(), for the countries table, you want to return the number of countries in the selected continent:
} else if tableView == countryTable {
if let selectedContinentRow = rowSelected() {
let selectedContinent = continentsArray[selectedContinentRow]
return self.worldDict[selectedContinent].count
}
return 0
}
For tableView(_:viewForTableColumn:row:), you want to return an element from the selected continent's array of countries:
} else if tableView == self.countryTable {
if let selectedContinentRow = rowSelected() {
let selectedContinent = continentsArray[selectedContinentRow]
return self.worldDict[selectedContinent][row]
}
}
Also, whenever the selected continent changes, you need to tell the countries table to reload its data:
func tableViewSelectionDidChange(notification: NSNotification) {
// ... whatever else ...
let tableView = notification.object as! NSTableView
if tableView == continentTable {
countryTable.reloadData()
}
}
I am trying to reorder a my Core Data list when moving cells in "Edit Mode". There seems to be helpful discussion in this area for Obj-c (see links below), but I can't find anything in Swift.
Has anyone come across any related documentation for Swift? Or would anyone be willing to translate the obj-c code to Swift? Thanks!
Obj-c links:
How can I maintain display order in UITableView using Core Data?
How to implement re-ordering of CoreData records?
Here is a nice way I do it. It also checks if the destination may not contain any data and you can also move accross sections.
isMoving will inhibit the delegate from firing off. You also need a sortorder attribute at your entity.
private func indexIsOutOfRange(indexPath:NSIndexPath) -> Bool {
if indexPath.section > self.fetchedResultsController.sections!.count - 1 {
return true
}
if indexPath.row > self.fetchedResultsController.sections![indexPath.section].objects!.count - 1 {
return true
}
return false
}
override func tableView(tableView: UITableView, moveRowAtIndexPath sourceIndexPath: NSIndexPath, toIndexPath destinationIndexPath: NSIndexPath)
{
if indexIsOutOfRange(destinationIndexPath) {
return
}
isMovingItem = true
if sourceIndexPath.section == destinationIndexPath.section {
if var todos = self.fetchedResultsController.sections![sourceIndexPath.section].objects {
let todo = todos[sourceIndexPath.row] as! FoodEntry
todos.removeAtIndex(sourceIndexPath.row)
todos.insert(todo, atIndex: destinationIndexPath.row)
var idx = 1
for todo in todos as! [FoodEntry] {
todo.sortOrder = NSNumber(integer: idx++)
}
try!managedObjectContext.save()
}
} else {
if var allObjectInSourceSection = fetchedResultsController.sections![sourceIndexPath.section].objects {
let object = allObjectInSourceSection[sourceIndexPath.row] as! FoodEntry
allObjectInSourceSection.removeAtIndex(sourceIndexPath.row)
for (index,object) in (allObjectInSourceSection as! [FoodEntry]).enumerate() {
object.sortOrder = NSNumber(integer: index)
}
if var allObjectInDestinationSection = fetchedResultsController.sections![destinationIndexPath.section].objects {
allObjectInDestinationSection.insert(object, atIndex: destinationIndexPath.row)
for (index,object) in (allObjectInDestinationSection as! [FoodEntry]).enumerate() {
object.sortOrder = NSNumber(integer: index)
object.section = NSNumber(integer: destinationIndexPath.section)
}
}
}
}
dispatch_async(dispatch_get_main_queue(), { () -> Void in
tableView.reloadRowsAtIndexPaths(tableView.indexPathsForVisibleRows!, withRowAnimation: .Fade)
})
isMovingItem = false
try!managedObjectContext.save()
fetch()
}