I am having an issue while using the RxJava concat operator. I have two observables, the first emits results from a server database and the other one emits results from the local database, and then I concat the :
// Uses a Realm in the UI thread
Observable<MyResult> remoteObservable = mRemoteDataSource.find(tId);
// Uses Retrofit
Observable<MyResult> localObservable = mLocalDataSource.find(tId);
Observable.concat(localObservable, remoteObservable)
.doOnNext(result -> /* Do my stuff */)
.observeOn(AndroidSchedulers.mainThread())
.doOnError(throwable -> throwable.printStackTrace())
.subscribe()
So this causes me problem, since I am not using subscribeOn() the concatenated observable is running on AndroidScheduler.MainThread() and this does not run the remote and it launches a NetworkOnMainThreadException.
If I implement a subscribeOn(Schedulers.computation()) I get Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created since of course the Observable is not running on the thread the Realm instance does exist.
I have searched in other questions and I have not gotten anything useful, I have checked the example made by realm: https://github.com/realm/realm-java/blob/master/examples/rxJavaExample/src/main/java/io/realm/examples/rxjava/retrofit/RetrofitExample.java but strangely I see that the retrofit observable is subscribed on nothing and it works.
Why does it work on the sample and in my code I cannot do the same? Any suggestion?
I believe you should use subscribeOn() in the right places.
// Uses a Realm in the UI thread
Observable<MyResult> realmObservable = mRealmDataSource.find(tId).subscribeOn(AndroidSchedulers.mainThread());
// Uses Retrofit
Observable<MyResult> retrofitObservable = mRetrofitDataSource.find(tId).subscribeOn(Subscribers.io());
Observable.concat(realmObservable, retrofitObservable)
.doOnNext(result -> /* Do my stuff */)
.subscribeOn(AndroidSchedulers.mainThread())
.observeOn(AndroidSchedulers.mainThread())
.doOnError(throwable -> throwable.printStackTrace())
.subscribe()
See if it fixes your issue.
You can concat your local and remote observables like below:
// Uses a Realm in the UI thread
Observable<MyResult> remoteObservable = mRemoteDataSource.find(tId);
// Uses Retrofit
Observable<MyResult> localObservable = mLocalDataSource.find(tId);
Observable.concat(localObservable, remoteObservable).first()
.map(new Func1<MyResult, MyResult>() {
#Override
public myResult call(MyResult result) {
if (result == null) {
throw new IllegalArgumentException();
}
return result;
}
});
And subscribe like below:
CompositeSubscription mCompositeSubscription = new CompositeSubscription();
final Subscription subscription = mRepo.find(tId
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<MyResult>() {
#Override
public void onCompleted() {
// Completed
}
#Override
public void onError(Throwable e) {
// onError
}
#Override
public void onNext(MyResult result) {
//onSuccess
}
});
mCompositeSubscription.add(subscription);
You can check this repo for RxJava + Retrofit + Realm
https://github.com/savepopulation/wikilight
Good luck!
Instead of using subscribeOn at mRealmDataSource.find(tId).subscribeOn(AndroidSchedulers.mainThread())
like said : https://stackoverflow.com/a/39304891/2425851
You can use Observable.defer
for example:
class RealmDataSource{
fun find(id: String): Observable<MyResult> {
// Default pattern for loading data on a background thread
return Observable.defer{
val realm = Realm.getInstance()
val query = realm
.where(MyResult::class.java)
val flowable =
if (realm.isAutoRefresh) {
query
.findAllAsync()
.asFlowable()
.filter(RealmResults::isLoaded)
} else {
Flowable.just(query.findAll())
}
return#defer flowable
.toObservable()
}
}
Then usage will be without subscribeOn
// Uses a Realm
Observable<MyResult> realmObservable = mRealmDataSource.find(tId);
// Uses Retrofit
Observable<MyResult> remoteObservable = mRemoteDataSource.find(tId);
For more info see https://realm.io/blog/realm-java-0-87-0/
Related
I am currently making a a leaderboard feature for my Mac OS X Unity game. I first tried Playfab but I kept getting an error saying "PlayFabException: Must be logged in to call this method PlayFab". I can't find a way to resolve this.
I have 2 scripts that does this, this is the code for the PlayFabManger script:
`using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using PlayFab;
using PlayFab.ClientModels;
using System;
public class PlayFabManager : MonoBehaviour
//public static PlayFabManager instance;
// Start is called before the first frame update
void Start()
{
//instance = this;
if (string.IsNullOrEmpty(PlayFabSettings.staticSettings.TitleId))
{
/*
Please change the titleId below to your own titleId from PlayFab Game Manager.
If you have already set the value in the Editor Extensions, this can be skipped.
*/
PlayFabSettings.staticSettings.TitleId = "F9F3D";
}
Login();
}
// Update is called once per frame
void Update()
{
}
void Login()
{
var request = new LoginWithCustomIDRequest
{
CustomId = SystemInfo.deviceUniqueIdentifier,
CreateAccount = true
};
PlayFabClientAPI.LoginWithCustomID(request, OnSuccess, OnError);
}
//private void OnLoginSuccess(LoginResult result)
//{
// //>> Call Client API here <<
// var getStoreItemsRequest = new GetStoreItemsRequest { StoreId = "[YourStoreId]" };// Please change this value to your own storeId from PlayFab Game Manager
// PlayFabClientAPI.GetStoreItems(getStoreItemsRequest, OnGetSuccess, OnError);
//}
void OnSuccess(LoginResult result)
{
print("Successful login create");
}
public void SendLeaderBoard(int score)
{
var request = new UpdatePlayerStatisticsRequest
{
Statistics = new List<StatisticUpdate>
{
new StatisticUpdate
{
StatisticName = "PlatformScore",
Value = score
}
}
};
PlayFabClientAPI.UpdatePlayerStatistics(request, OnLeaderboardUpdate, OnError);
}
void OnLeaderboardUpdate(UpdatePlayerStatisticsResult result)
{
print("Successful leaderboard sent");
}
void OnError(PlayFabError error)
{
print("Error while logging in/creating account!");
print(error.GenerateErrorReport());
}
public void GetLeaderBoard()
{
var request = new GetLeaderboardRequest
{
StatisticName = "PlatformScore",
StartPosition = 0,
MaxResultsCount = 10
};
PlayFabClientAPI.GetLeaderboard(request, OnLeaderboardGet, OnError);
}
private void OnLeaderboardGet(GetLeaderboardResult result)
{
foreach (var item in result.Leaderboard)
{
print(item.Position + " " + item.PlayFabId + " " + item.StatValue);
}
}
}
`
I also have a line of code in another script that is called at the start method and refers to the above script, where I pass in a Playerprefs.GetInt variable:
playFabManager.SendLeaderBoard(PlayerPrefs.GetInt("TtlPoints"));
Does anyone have any idea on resolving this error? Is there an easier way to achieve this leaderboard feature on Mac OS X using other extensions such as firebase or pubnub?
Sorry for my English, looking forward to hearing from you.
PubNub awesome, Beamable uses them for fabs leaderboards for Unity! Check them out.
I'll take the Firebase answer.
If you go the Firebase route, there is not an out of the box Leaderboard solution. There is an example open source repository that you can use to implement leaderboards on Realtime Database that should be relatively simple to implement.
Your second problem is that although Realtime Database does work on desktop (and the leaderboard in particular hasn't given me any issues), it is currently a beta feature only intended for use during development. If you file a related bug, the team will work to fix it, but it will probably be prioritized behind any mobile-features. You could implement it all using the REST API directly, but at this point the official Unity samples and documentation won't apply.
So i'm testing with Blazor and gRPC and my dificulty at the moment is on how to pass the content of a variable that is on a class, specifically the gRPC GreeterService Class to the Blazor page when new information arrives. Notice that my aplication is a client and a server, and i make an initial comunication for the server and then the server starts to send to the client data(numbers) in unary mode, every time it has new data to send. I have all this working, but now i'm left it that final implementation.
This is my Blazor page
#page "/greeter"
#inject GrpcService1.GreeterService GreeterService1
#using BlazorApp1.Data
<h1>Grpc Connection</h1>
<input type="text" #bind="#myID" />
<button #onclick="#SayHello">SayHello</button>
<p>#Greetmsg</p>
<p></p>
#code {
string Name;
string Greetmsg;
async Task SayHello()
{
this.Greetmsg = await this.GreeterService1.SayHello(this.myID);
}
}
The method that later receives the communication from the server if the hello is accepted there is something like this:
public override async Task<RequestResponse> GiveNumbers(BalconyFullUpdate request, ServerCallContext context)
{
RequestResponse resp = new RequestResponse { RequestAccepted = false };
if (request.Token == publicAuthToken)
{
number = request.Number;
resp = true;
}
return await Task.FromResult(resp);
}
Every time that a new number arrives i want to show it in the UI.
Another way i could do this was, within a while condition, i could do a call to the server requesting a new number just like the SayHello request, that simply awaits for a server response, that only will come when he has a new number to send. When it comes the UI is updated. I'm just reluctant to do it this way because i'm afraid that for some reason the client request is forgotten and the client just sit's there waiting for a response that will never come. I know that i could implement a timeout on the client side to handle that, and on the server maybe i could pause the response, with a thread pause or something like that, and when the method that generates the new number has a new number, it could unpause the response to the client(no clue on how to do that). This last solution looks to me much more difficult to do than the first one.
What are your thoughts about it? And solutions..
##################### UPDATE ##########################
Now i'm trying to use a singleton, grab its instance in the Blazor page, and subcribe to a inner event of his.
This is the singleton:
public class ThreadSafeSingletonString
{
private static ThreadSafeSingletonString _instance;
private static readonly object _padlock = new object();
private ThreadSafeSingletonString()
{
}
public static ThreadSafeSingletonString Instance
{
get
{
if (_instance == null)
{
lock(_padlock)
{
if (_instance == null)
{
_instance = new ThreadSafeSingletonString();
_instance.number="";
}
}
}
return _instance;
}
set
{
_instance.number= value.number;
_instance.NotifyDataChanged();
}
}
public int number{ get; set; }
public event Action OnChange;
private void NotifyDataChanged() => OnChange?.Invoke();
And in Blazor page in code section i have:
protected override void OnInitialized()
{
threadSafeSingleton.OnChange += updateNumber();
}
public System.Action updateNumber()
{
this.fromrefresh = threadSafeSingleton.number + " que vem.";
Console.WriteLine("Passou pelo UpdateNumber");
this.StateHasChanged();
return StateHasChanged;
}
Unfortunatly the updatenumber function never gets executed...
To force a refresh of the ui you can call the StateHasChanged() method on your component:
https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.components.componentbase.statehaschanged?view=aspnetcore-3.1
Notifies the component that its state has changed. When applicable, this will cause the component to be re-rendered.
Hope this helps
Simple Request
After fully understanding that your problem is just to Update the Page not to get unsyncronous messages from the server with a bi directional connection. So jou just have to change your page like (please not there is no need to change the files generated by gRPC, I called it Number.proto so my service is named NumberService):
async Task SayHello()
{
//Request via gRPC
var channel = new Channel(Host + ":" + Port, ChannelCredentials.Insecure);
var client = new this.NumberService.NumberServiceClient(channel);
var request = new Number{
identification = "ABC"
};
var result = await client.SendNumber(request).RequestAccepted;
await channel.ShutdownAsync();
//Update page
this.Greetmsg = result;
InvokeAsync(StateHasChanged);//Required to refresh page
}
Bi Directional
For making a continious bi directional connection you need to change the proto file to use streams like:
service ChatService {
rpc chat(stream ChatMessage) returns (stream ChatMessageFromServer);
}
This Chant sample is from the https://github.com/meteatamel/grpc-samples-dotnet
The main challenge on this is do divide the task waiting for the gRPC server from the client. I found out that BackgroundService is good for this. So create a Service inherited from BackgroundService where place the while loop waiting for the server in the ExecuteAsyncmethod. Also define a Action callback to update the page (alternative you can use an event)
public class MyChatService : BackgroundService
{
Random _random = new Random();
public Action<int> Callback { get; set; }
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
// Replace next lines with the code request and wait for server...
using (_call = _chatService.chat())
{
// Read messages from the response stream
while (await _call.ResponseStream.MoveNext(CancellationToken.None))
{
var serverMessage = _call.ResponseStream.Current;
var otherClientMessage = serverMessage.Message;
var displayMessage = string.Format("{0}:{1}{2}", otherClientMessage.From, otherClientMessage.Message, Environment.NewLine);
if (Callback != null) Callback(displayMessage);
}
// Format and display the message
}
}
}
}
On the page init and the BackgroundService and set the callback:
#page "/greeter"
#using System.Threading
<p>Current Number: #currentNumber</p>
#code {
int currentNumber = 0;
MyChatService myChatService;
protected override async Task OnInitializedAsync()
{
myChatService = new MyChatService();
myChatService.Callback = i =>
{
currentNumber = i;
InvokeAsync(StateHasChanged);
};
await myChatService.StartAsync(new CancellationToken());
}
}
More information on BackgroundService in .net core can be found here: https://gunnarpeipman.com/dotnet-core-worker-service/
I am trying to develop a xamarin forms app in which user can make call
(Navigate to dialer) from taping on number showed on app.In android I accomplished this through dependency service.But in ios I am stuck.I heard about callkit.I saw the documentation of it in https://learn.microsoft.com/en-us/xamarin/ios/platform/callkit?tabs=windows. But how can I actually implement on this in my App? I added all the classes in that document to my app.But how I can make the call from xamal.cs to the ios specified code? By using Dependency service?
Edit: I know how to navigate app to dialer or phone app. Why I am using callkit is I want to get the call duartion.
I created an Instance
public interface IosCallerDialer
{
void StartCall();
}
Implementation on ios
class IosCallDial: IosCallerDialer
{
private CXCallController CallController = new CXCallController();
private void SendTransactionRequest(CXTransaction transaction)
{
// Send request to call controller
CallController.RequestTransaction(transaction, (error) => {
// Was there an error?
if (error == null)
{
// No, report success
Console.WriteLine("Transaction request sent successfully.");
}
else
{
// Yes, report error
Console.WriteLine("Error requesting transaction: {0}", error);
}
});
}
public void StartCall()
{
// Build call action
string contact = "8547085532";
var handle = new CXHandle(CXHandleType.Generic, contact);
var startCallAction = new CXStartCallAction(new NSUuid(), handle);
// Create transaction
var transaction = new CXTransaction(startCallAction);
// Inform system of call request
SendTransactionRequest(transaction);
}
}
My xaml.cs
async void btnCall_Clicked(object sender, System.EventArgs e)
{
DependencyService.Get<IosCallerDialer>().StartCall();
}
Apart this I added all the classes defined in the document.I want only outgoing call. Is this proper way? I cant find any tutorials regarding callkit on xamarin. Any help is appreciated.
EDIT: I understand Callkit only for voip. So is there any other workaround like starting a timer when moves to phone app and stop timer when returns to app? Is it possible? Please provide any insights.
You can try the code below to detect the state of incoming call.
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
{
//
// This method is invoked when the application has loaded and is ready to run. In this
// method you should instantiate the window, load the UI into it and then make the window
// visible.
//
// You have 17 seconds to return from this method, or iOS will terminate your application.
//
public CTCallCenter c { get; set; }
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();
LoadApplication(new App());
c = new CTCallCenter();
c.CallEventHandler = delegate (CTCall call)
{
if (call.CallState == call.StateIncoming)
{
//start the timer
}
else if (call.CallState == call.StateDialing)
{
}
else if (call.CallState == call.StateConnected)
{
}
else if(call.CallState == call.StateDisconnected)
{
//end the timer
//use messagecenter to send duartion
MessagingCenter.Send<Object>(new Object(), "Hi");
}
};
return base.FinishedLaunching(app, options);
}
}
And any Where in Xamarin.forms:
MessagingCenter.Subscribe<Object>(this, "Hi", (sender) => {
// do something whenever the "Hi" message is sent
Console.WriteLine("hihihi");
});
Note: I haven't test it on my side yet as I don't have enough device. You can test it and let me know if it works.
Hello StackOverflow community,
I know there's a lot of code in this post, but I wanted to give you guys, the community as good of a picture as possible as to what is going on here so that maybe someone can help me figure out what my issue is.
Recently for a project I'm working on we've decided to upgrade from MvvmCross 5.7.0 to 6.2.2. I've managed to get our UWP app to successfully complete the initialization and setup process. The first viewmodel for which we register the app start also starts initializing. However, I'm finding that my vm initialization hangs at a particular line of code (shown in the code below). The weirdest part though is similar methods called in the app initialization code run perfectly fine without hanging/deadlock, so I'm not sure what's different Here's a simplified version of my viewmodel code to illustrate:
public class MyViewModel : BaseAuthenticatedTabBarViewModel, IMvxViewModel<int>
{
private int? _settingValue;
public override async Task Initialize()
{
//Some irrelevant initialization code
Exception e = null;
try
{
//This line of code never returns
_settingValue = _settingValue ?? await AppSettingService.GetSettingValue();
}
catch (Exception ex)
{
e = ex;
}
if (e != null)
{
await HandleCatastrophicError(e);
}
}
}
The AppSettingService.GetSettingValue() method looks like this:
public async Task<int?> GetCurrentEventId()
{
return await GetNullableIntSetting("SettingValue");
}
private static async Task<int?> GetNullableIntSetting(string key)
{
try
{
var setting = await SettingDataService.SettingByName(key);
if (setting != null)
{
return string.IsNullOrEmpty(setting.Value) ? (int?)null : Convert.ToInt32(setting.Value);
}
}
catch (Exception ex)
{
//Handle the exception
}
return null;
}
All the code for SettingDataService:
public class SettingDataService : DataService<SettingDataModel>, ISettingDataService
{
public async Task<SettingDataModel> SettingByName(string name)
{
try
{
var values = (await WhereAsync(e => e.Name == name));
return values.FirstOrDefault();
}
catch(Exception ex)
{
//Handle the exception
}
return null;
}
}
Finally, the implementation for WhereAsync() is in a class called DataService and is as follows:
public virtual async Task<IEnumerable<T>> WhereAsync(System.Linq.Expressions.Expression<Func<T, bool>> condition, SQLiteAsyncConnection connection = null)
{
return await (connection ?? await GetConnectionAsync())
.Table<T>()
.Where(condition)
.ToListAsync();
}
Thank you very much for your help in advance
Edit: Forgot to also add this crucial bit of code to help you guys even further:
protected async Task<SQLiteAsyncConnection> GetConnectionAsync()
{
SQLiteAsyncConnection connection = null;
while (true)
{
try
{
connection = Factory.Create(App.DatabaseName);
// This line of code is the culprit. For some reason this hangs and I can't figure out why.
await connection.CreateTableAsync<T>();
break;
}
catch (SQLiteException ex)
{
if (ex.Result != Result.CannotOpen && ex.Result != Result.Busy && ex.Result != Result.Locked)
{
throw;
}
}
await Task.Delay(20);
}
return connection;
}
I'm suspecting that you are calling Task.Wait or Task<T>.Result somewhere further up your call stack. Or if you're not doing it, MvvmCross is probably doing it for you. This will cause a deadlock when called from a UI context.
Personally, I prefer the approach that ViewModels should always be constructed synchronously, and cannot have an asynchronous "initialization". That is, they must construct themselves (synchronously) into a "loading" state, and this construction can kick off an asynchronous operation that will later update them into a "loaded" state. The synchronous-initialization pattern means there's never an unnecessary delay when changing views; your users may only see a spinner or a loading message, but at least they'll see something. See my article on async MVVM data binding for a pattern that helps with this, and note that there's a newer version of the helper types in that article.
Using the Twitch API and vert.x - I'm looking to continuously send requests to Twitch's API using a WebClient and Twitch's cursor response to go page by page. However I'm not sure how to go back and keep doing queries until a condition is met due to vert.x's asynchronous nature.
Here's my code so far
public void getEntireStreamList(Handler<AsyncResult<JsonObject>> handler) {
JsonObject data = new JsonObject();
getLiveChannels(100, result -> {
if(result.succeeded()) {
JsonObject json = result.result();
String cursor = json.getJsonObject("pagination").getString("cursor");
data.put("data", json.getJsonArray("data"));
if(json.getJsonArray("data").size() < 100) { // IF NOT LAST PAGE
// GO BACK AND DO AGAIN WITH CURSOR IN REQUEST
}
handler.handle(Future.succeededFuture(data));
} else
handler.handle(Future.failedFuture(result.cause()));
});
}
Ideally I'd be able to call getLiveChannels with the cursor String from the previous request to continue the search.
You will need to use Future composition.
Here's my code for your problem:
public void getEntireStreamList(Handler<AsyncResult<JsonObject>> handler) {
JsonArray data = new JsonArray();
// create initial Future for first function call
Future<JsonObject> initFuture = Future.future();
// complete Future when getLiveChannels completes
// fail on exception
getLiveChannels(100, initFuture.completer());
// Create a callback that returns a Future
// for composition.
final AtomicReference<Function<JsonObject, Future<JsonObject>>> callback = new AtomicReference<>();
// Create Function that calls composition with itself.
// This is similar to recursion.
Function<JsonObject, Future<JsonObject>> cb = new Function<JsonObject, Future<JsonObject>>() {
#Override
public Future<JsonObject> apply(JsonObject json) {
// new Future to return
Future<JsonObject> f = Future.future();
// Do what you wanna do with the data
String cursor = json.getJsonObject("pagination").getString("cursor");
data.addAll(json.getJsonArray("data"));
// IF NOT LAST PAGE
if(json.getJsonArray("data").size() == 100) {
// get more live channels with cursor
getLiveChannels(100, cursor, f.completer());
// return composed Future
return f.compose(this);
}
// Otherwise return completed Future with results.
f.complete(new JsonObject().put("data", data));
return f;
}
};
Future<JsonObject> composite = initFuture.compose(cb);
// Set handler on composite Future (ALL composed futures together)
composite.setHandler(result -> handler.handle(result));
}
The code + comments should speak for themselves if you read the Vert.x docs on sequential Future composition.