this is the part where it's not working. i'm trying to fetch data from a sever using retrofit. i have created api interface. which will establish connection and in the fragment where i have to retrieve data implementing that but it doesn't work. the android studio is not able to resolve call.enqueue() .
call.enqueue (new Callback<List<Student>>() {
#Override
public void onResponse(Call<List<Student> call, Response<List<Student>> response) {
List<Student> studata = response.body();
}
#Override
public void onFailure(Call<List<Student>> call, Throwable t) {
Toast.makeText(mActivity.getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
}
});
Check your imports at the top of that file. Make sure your import for Call is
import retrofit2.Call;
and not import okhttp3.Call; or import android.telecom.Call; or some other random Call.
In your interface, change the return type of the method to Call<your-return-type>.
Related
With AspNetCore.SignalR (1.0.0 preview1-final) and AspNetCore.All (2.0.6), how can I invoke a method on a hub in server code that is not directly in a Controller and is in a class that cannot be made via Dependency Injection?
Most examples assume the server code is in a Controller and should 'ask' for the hub via an injectable parameter in a class that will created by DI.
I want to be able to call the hub's method from server code at any time, in code that is not injected. The old SignalR had a GlobalHost that enabled this approach. Basically, I need the hub to be a global singleton.
Now, everything seems to be dependent on using Dependency Injection, which is introducing a dependency that I don't want!
I've seen this request voiced in a number of places, but haven't found a working solution.
Edit
To be more clear, all I need is to be able to later access the hubs that I've registered in the Configure routine of the Startup class:
app.UseSignalR(routes =>
{
routes.MapHub<PublicHubCore>("/public");
routes.MapHub<AnalyzeHubCore>("/analyze");
routes.MapHub<ImportHubCore>("/import");
routes.MapHub<MainHubCore>("/main");
routes.MapHub<FrontDeskHubCore>("/frontdesk");
routes.MapHub<RollCallHubCore>("/rollcall");
// etc.
// etc.
});
If I register them like this:
services.AddSingleton<IPublicHub, PublicHubCore>();
it doesn't work, since I get back an uninitiated Hub.
No It's not possible. See "official" answer from david fowler https://github.com/aspnet/SignalR/issues/1831#issuecomment-378285819
How to inject your hubContext:
Best solution is to inject your hubcontext like IHubContext<TheHubWhichYouNeedThere> hubcontext
into the constructor.
See for more details:
Call SignalR Core Hub method from Controller
Thanks to those who helped with this. Here's what I've ended up on for now...
In my project, I can call something like this from anywhere:
Startup.GetService<IMyHubHelper>().SendOutAlert(2);
To make this work, I have these extra lines in Startup.cs to give me easy access to the dependency injection service provider (unrelated to SignalR):
public static IServiceProvider ServiceProvider { get; private set; }
public static T GetService<T>() { return ServiceProvider.GetRequiredService<T>(); }
public void Configure(IServiceProvider serviceProvider){
ServiceProvider = serviceProvider;
}
The normal SignalR setup calls for:
public void Configure(IApplicationBuilder app){
// merge with existing Configure routine
app.UseSignalR(routes =>
{
routes.MapHub<MyHub>("/myHub");
});
}
I don't want all my code to have to invoke the raw SignalR methods directly so I make a helper class for each. I register that helper in the DI container:
public void ConfigureServices(IServiceCollection services){
services.AddSingleton<IMyHubHelper, MyHubHelper>();
}
Here's how I made the MyHub set of classes:
using Microsoft.AspNetCore.SignalR;
using System.Threading.Tasks;
public class MyHub : Hub { }
public interface IMyHubHelper
{
void SendOutAlert(int alertNumber);
}
public class MyHubHelper : IMyHubHelper
{
public IHubContext<MyHub> HubContext { get; }
public MyHubHelper(IHubContext<MyHub> hubContext)
{
HubContext = hubContext;
}
public void SendOutAlert(int alertNumber)
{
// do anything you want to do here, this is just an example
var msg = Startup.GetService<IAlertGenerator>(alertNumber)
HubContext.Clients.All.SendAsync("serverAlert", alertNumber, msg);
}
}
This is a nice solution. In .NET Core 2.1 the service provider is disposed and you get cannot access disposed object. The fix is to create a scope:
public void Configure(IApplicationBuilder app, IHostingEnvironment env, IServiceProvider serviceProvider)
{
ServiceProvider = serviceProvider.CreateScope().ServiceProvider;
I have developed own idGenerator based on Hazelcast IdGenerator class (with storing each last_used_id into db). Now I want to run hazelcast cluster as a single java application and my web-application as other app (web-application restart shouldn't move id values to next block). I move MyIdGeneratorProxy and MyIdGeneratorService to new application, run it, run web-application as a hazelcast-client and get
IllegalArgumentException: No factory registered for service: ecs:impl:idGeneratorService
It was okay when client and server were the same application.
It seems it's unable to process without some clientProxy. I have compared IdGeneratorProxy and ClientIdGeneratorProxy and it looks the same. What is the idea? How to write client proxy for services? I have found no documentation yet. Is direction of investigations correct? I thought it is possible to divide hazelcast inner services (like a id generator service) and my business-processes. Should I store custom ClientProxy (for custom spi) in my web-application?
This is a demo how to create a client proxy, the missing part CustomClientProxy function call, is quit complicated(more like a server proxy,here is called ReadRequest, the server is called Operation), you can find a how AtomicLong implement.For every client proxy method you have to make a request.
#Test
public void client() throws InterruptedException, IOException
{
ClientConfig cfg = new XmlClientConfigBuilder("hazelcast-client.xml").build();
ServiceConfig serviceConfig = new ServiceConfig();
serviceConfig.setName(ConnectorService.NAME)
.setClassName(ConnectorService.class.getCanonicalName())
.setEnabled(true);
ProxyFactoryConfig proxyFactoryConfig = new ProxyFactoryConfig();
proxyFactoryConfig.setService(ConnectorService.NAME);
proxyFactoryConfig.setClassName(CustomProxyFactory.class.getName());
cfg.addProxyFactoryConfig(proxyFactoryConfig);
HazelcastInstance hz = HazelcastClient.newHazelcastClient(cfg);
Thread.sleep(1000);
for (int i = 0; i < 10; i++)
{
Connector c = hz.getDistributedObject(ConnectorService.NAME, "Connector:" + ThreadLocalRandom.current()
.nextInt(10000));
System.out.println(c.snapshot());
}
}
private static class CustomProxyFactory implements ClientProxyFactory
{
#Override
public ClientProxy create(String id)
{
return new CustomClientProxy(ConnectorService.NAME, id);
}
}
private static class CustomClientProxy extends ClientProxy implements Connector
{
protected CustomClientProxy(String serviceName, String objectName)
{
super(serviceName, objectName);
}
#Override
public ConnectorState snapshot()
{
return null;
}
#Override
public void loadState(ConnectorState state)
{
}
#Override
public boolean reconnect(HostNode node)
{
return false;
}
#Override
public boolean connect()
{
return false;
}
}
EDIT
In hazelcast the IdGenerate is implemented as a wrapper for AtomicLong, you should implement you IdGenerate by you own, instead of extend IdGenerate.
So you have to implement these(more like a todo list XD):
API
interface MyIdGenerate
Server
MyIdGenerateService
MyIdGenerateProxy
MyIdGenerateXXXOperation
Client
ClientMyIdGenerateFactory
ClientMyIdGenerateProxy
MyIdGenerateXXXRequest
I also made a sequence(same as IdGenerate) here, this is backed by zookeeper or redis,also it's easy to add a db backend,too.I will integrate to hazelcast if I got time.
I created an Interface class:
package userclasses;
import com.codename1.system.NativeInterface;
public interface NativeJ2MEInterface extends NativeInterface {
public void pollBackground();
}
This is the native class - after I edited it:
package userclasses;
import userclasses.StateMachine;
public class NativeJ2MEInterfaceImpl {
public void pollBackground() {
try {
Date now = new Date();
long timeToRun = now.getTime() + (1000 * 60 );
System.out.println("RUNNNNNNN forest runnn!");
PushRegistry.registerAlarm(StateMachine.class.getName(), timeToRun);
}
catch (Exception e) {
System.out.println("EXC-1:"+e.getMessage());
}
}
public boolean isSupported() {
return true;
}
}
I want to call the javax.microedition.io.PushRegistry registerAlarm method, but my Codename One J2ME build fails saying:
error: cannot find symbol
PushRegistry.registerAlarm(StateMachine.class.getName(), timeToRun);
I added a midp_2.1.jar to the native j2me directory, but it did not work.
How can I get this to work? Or how can I directly access j2me alarm API?
Don't add the jar, it will get packaged into the final build.
Try setting the build argument j2me.ashaNative=true.
With MVC4 I was able to create and register a global action filter that would check the model state prior to the action's execution and return the serialized ModelState before any damage could be done.
public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
{
if (!actionContext.ModelState.IsValid)
{
actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState);
}
}
However, with MVC5, I am having trouble finding Request and therefore CreateErrorResponse
public override void OnActionExecuting(ActionExecutingContext nActionExecutingContext)
{
if (!nActionExecutingContext.Controller.ViewData.ModelState.IsValid)
{
nActionExecutingContext.Result = // Where is Request.CreateErrorResponse ?
}
}
I realize that I could create a custom response class to assign to Result but I'd rather use what's built-in if CreateErrorResponse is still available.
Any idea where I can find it relative to an ActionExecutingContext in MVC5 / Web API 2?
I know this is an old question but I recently had the same problem and solved it using
public override void OnActionExecuting(ActionExecutingContext context)
{
if (!context.ModelState.IsValid)
{
context.Result = new BadRequestObjectResult(context.ModelState);
}
}
I was trying to use the cool Insight.Database micro ORM and run into a Not Implemeneted exception everytime I try to invoke the InsertCustomer method in the CustomerRepository.Any help would be appreciated
Update: I made sure that the method name matches the sql server stored procedure name
public class CustomerRepository
{
private ICustomerRepository _repo;
public static async Task<int> InsertCustomer(Customer cust)
{
var _repo = ConfigSettings.CustomerRepository;
return await _repo.InsertCustomer(cust);
}
}
public class ConfigSettings
{
private static ICustomerRepository _customerRepository;
public static ICustomerRepository CustomerRepository
{
get
{
if (_customerRepository == null)
{
_customerRepository = new SqlConnection(ConfigurationManager.ConnectionStrings["CustomerService_Conn_String"].ConnectionString).AsParallel<ICustomerRepository>();
}
return _customerRepository;
}
}
}
[Sql(Schema="dbo")]
public interface ICustomerRepository
{
[Sql("dbo.InsertCustomer")]
Task<int> InsertCustomer(Customer cust);
}
If you're getting a NotImplementedException, and running v4.1.0 to 4.1.3 you're probably running into a problem registering your database provider.
I recommend using v4.1.4 or later and making sure you register the provider for your database.
See
https://github.com/jonwagner/Insight.Database/wiki/Installing-Insight
If you have any more problems, you can post an issue on github.