I have an application that accepts push notifications. I have to write the push notifications to the database. The problem is that in the database it writes only the last message (after I re-enter the application) and when the application is in the background and when in the foreground. What can be done to keep the database up-to-date when new data arrives?
I accept push, after which I write its data into variables
[Service]
[IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
public class MyFirebaseMessagingService : FirebaseMessagingService
{
const string TAG = "MyFirebaseMsgService";
public override void HandleIntent(Intent intent)
{
try
{
if (intent.Extras != null)
{
var builder = new RemoteMessage.Builder("MyFirebaseMessagingService");
foreach (string key in intent.Extras.KeySet())
{
builder.AddData(key, intent.Extras.Get(key).ToString());
}
this.OnMessageReceived(builder.Build());
}
else
{
base.HandleIntent(intent);
}
}
catch (Exception)
{
base.HandleIntent(intent);
}
}
public override void OnMessageReceived(RemoteMessage message)
{
Log.Debug(TAG, "From: " + message.From);
Log.Debug(TAG, "Notification Message Body: " + message.GetNotification().Body);
SendNotification(message.GetNotification().Body, message.Data, message.GetNotification().Title);
// Here I write the push - notification data into variables
X.Instance.title = message.GetNotification().Title;
X.Instance.body = message.GetNotification().Body;
}
private void OnStartCommand()
{
throw new NotImplementedException();
}
public class X
{
public static X Instance = new X();
public string title;
public string body;
}
Here in this class I fill the database:
[Service]
[Activity(Label = "Message")]
public class FormMessageActivity : Activity
{
ListView lstData;
List<Message> lstSource = new List<Message>();
DataBase db;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.FormMessage);
db = new DataBase();
db.CreateDataBase();
lstData = FindViewById<ListView>(Resource.Id.listView);
Message message = new Message()
{
//And here I add to the database
Some = MyFirebaseMessagingService.X.Instance.title,
Notification = MyFirebaseMessagingService.X.Instance.body
};
if (message.Notification != null)
{
db.InsertIntoTableMessage(message);
LoadData();
}
LoadData();
lstData.ItemClick += (s, e) =>
{
//Set background for selected item
for (int i = 0; i < lstData.Count; i++)
{
if (e.Position == i) StartActivity(typeof(MessageActivity));
}
};
}
public void LoadData()
{
lstSource = db.SelectTableMessage();
var adapter = new ListViewAdapter(this, lstSource);
lstData.Adapter = adapter;
}
}
From Your Code it seems like you're creating a DB instance in the onCreate and inputing data in same onCreate method. I can't see how your db is implemented or what kind of db it is, but i would suggest you input your notification in the Db in the OnMessageReceived handler which is called every-time you receive a new notification and not in your onCreate because onCreate is called sparingly and due to certain device configurations like orientation changes.
Related
I'm using the Quartz.NET library to create a job in my C# application.
I have some registers in my database, so I have a table wich contains a column called "start_date". The job runs every 50 seconds, so I compare the dates from the column "start_date" with the date of my computer, and if the dates are equal, I want to instantiate a new Windows Form with a message and a button.
At the moment, the new Windows Form is opening at the right moment, but the message is not showed and the window stops to respond.
Basically, in my code I have something like this:
FormMessage.cs
public partial class FormMessage : Form
{
public FormMessage()
{
InitializeComponent();
}
public FormMessage(double minutes)
{
InitializeComponent();
string message = string.Format("You have {0} minutes!", minutes);
lblMessage.Text = message ;
}
private void btnOK_Click(object sender, EventArgs e)
{
this.Close();
}
}
JobMessage.cs
public class JobMessage: IJob
{
List<Information> informations;
public void Execute(IJobExecutionContext context)
{
//Class with methods to get registers from database.
InformationAPI infoAPI = new InformationAPI();
informations = infoAPI.GetInformations();
foreach (Information info in informations)
{
DateTime computerDateTime = DateTime.Now;
DateTime infoDateTime = info.StartDate;
double difference;
if (DateTime.Compare(computerDateTime, infoDateTime) < 0)
{
difference = Math.Round(infoDateTime.Subtract(computerDateTime).TotalMinutes);
if (difference == 5)
{
FormMessage formMessage = new FormMessage(difference);
formMessage.Show();
}
}
}
}
}
Someone have some idea of the reason why the FormMessage window stops to respond?
Thank you for your attention!
You can try Quartz Listeners to let them open the form to show the data and keep the execution out of the job scope:
Action<IJobExecutionContext, JobExecutionException> listenerAction = (c, e) => {
var dataMap = context.GetJobDetail().GetJobDataMap();
var difference = dataMap.GetIntValue("difference");
FormMessage formMessage = new FormMessage(difference);
formMessage.Show();
}
var listener = new SyncJobListener(listenerAction);
And add the listener in to the scheduler:
scheduler.ListenerManager.AddJobListener(listener,
GroupMatcher<JobKey>.GroupEquals("GroupName"));
Using this SyncJobListener:
public class SyncJobListener : IJobListener
{
private readonly Action<IJobExecutionContext, JobExecutionException> _syncExecuted;
public string Name { get; private set; }
public SyncJobListener(
Action<IJobExecutionContext, JobExecutionException> syncExecuted
)
{
Name = Guid.NewGuid().ToString();
_syncExecuted = syncExecuted;
}
public void JobToBeExecuted(IJobExecutionContext context)
{
}
public void JobExecutionVetoed(IJobExecutionContext context)
{
}
public void JobWasExecuted(IJobExecutionContext context, JobExecutionException jobException)
{
_syncExecuted(context, jobException);
}
}
I have not tested this so if the dataMap does not have any data, you are going to need to allow the persistance:
[PersistJobDataAfterExecution]
[DisallowConcurrentExecution]
public class JobMessage: IJob {}
I've just started looking into Xamarin and just can not to wrap around my head how to make multiple Activities have a reference same instance of service.
I am starting KeyPressedReceiver from MainActivity and start listening for power button being pressed.
When three click are being made, I am calling service method InitCancelActivity, which starts playing mp3 file and opens CancelActivity.
In CancelActivity there is a text field and a button. And when user press this button, I want the value from text field to be passes to the GeneralService method KillAlert.
The question is how to reference instance of GeneralService (which is already created) from CancelActivity, so I could call KillAlert?
And this part
if (_service == null)
_service = new GeneralService();
looks absolutely wrong. Should I instantiate it in MainActivity and pass to a KeyPressedReceiver constructor?
[Activity(Label = "TTTT", MainLauncher = true, Icon = "#drawable/icon")]
public class MainActivity : Activity
{
KeyPressedReceiver receiver;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
receiver = new KeyPressedReceiver();
RegisterReceiver(receiver, new IntentFilter(Intent.ActionScreenOn));
}
}
[BroadcastReceiver(Enabled = true)]
public class KeyPressedReceiver : BroadcastReceiver
{
private GeneralService _service;
private int _clicks = 0;
public override void OnReceive(Context context, Intent intent)
{
if (_service == null)
_service = new GeneralService();
_clicks++;
if (_clicks > 5)
{
_service.InitCancelActivity();
}
}
}
[Service(Name = "com.ff.GeneralService")]
public class GeneralService : Service {
private readonly Android.Media.MediaPlayer _player;
public GeneralService()
{
_player = new Android.Media.MediaPlayer();
}
public void RaiseAlert()
{
// start playing .mp3 file
}
public void KillAlert(string pass)
{
// stop playing .mp3 file
}
public void InitCancelActivity()
{
this.RaiseAlert();
var i = new Intent(this, typeof(CancelActivity));
i.SetFlags(ActivityFlags.NewTask);
this.StartActivity(i);
}
}
[Activity(Label = "CancelActivity")]
public class CancelActivity : Activity
{
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.cancel);
this.FindViewById(Resource.Id.cancelButtonYes).Click += delegate
{
var password = this.FindViewById(Resource.Id.cancelPassword);
// call KillAlert method from GeneralServic
};
}
}
Create static GeneralService instance and use in Cancel Activity.
for example
[Service(Name = "com.ff.GeneralService")]
public class GeneralService : Service {
private readonly Android.Media.MediaPlayer _player;
public static generalService;
public GeneralService()
{
_player = new Android.Media.MediaPlayer();
generalService=this
}
public void RaiseAlert()
{
// start playing .mp3 file
}
public void KillAlert(string pass)
{
// stop playing .mp3 file
}
public void InitCancelActivity()
{
this.RaiseAlert();
var i = new Intent(this, typeof(CancelActivity));
i.SetFlags(ActivityFlags.NewTask);
this.StartActivity(i);
}
}
and use in CancelActivity like below example
[Activity(Label = "CancelActivity")]
public class CancelActivity : Activity
{
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.cancel);
this.FindViewById(Resource.Id.cancelButtonYes).Click += delegate
{
var password = this.FindViewById(Resource.Id.cancelPassword);
// call KillAlert method from GeneralServic
GeneralService.generalService.KillAlert(password.TEXT);
};
}
}
I'm new in Microsoft Message Queue in Windows Server, I need to push, if the EmployeeID is NULL.
The Employee Model Class is
public class Employee
{
public string EmployeeID { get; set; }
public string EmployeeName { get; set; }
}
public void ValidationProcess(Employee emp)
{
if((emp != null) || (emp.EmployeeID == null))
{
// Push into Validation Exception Queue using MSMQ
}
}
Once the Data pushed into that Validation Exception Queue, it should be processed by separate process. Every 1hr the process need to initiate and it should call the following method
public void ValidationExceptionProcess(object obj)
{
// Some Inner Process
// Log the Error
}
Kindly guide me how to create and process it.
First Step:
Install MSMQs as a windows feature on the server/pc
Then:
- Create the queue if it does not exist
- Push the message in the queue asynchronously
Useful guide
Code example for pushing and retrieving messages from msmq:
public class ExceptionMSMQ
{
private static readonly string description = "Example description";
private static readonly string path = #".\Private$\myqueue";
private static MessageQueue exceptionQueue;
public static MessageQueue ExceptionQueue
{
get
{
if (exceptionQueue == null)
{
try
{
if (MessageQueue.Exists(path))
{
exceptionQueue = new MessageQueue(path);
exceptionQueue.Label = description;
}
else
{
MessageQueue.Create(path);
exceptionQueue = new MessageQueue(path);
exceptionQueue.Label = description;
}
}
catch
{
throw;
}
finally
{
exceptionQueue.Dispose();
}
}
return exceptionQueue;
}
}
public static void PushMessage(string message)
{
ExceptionQueue.Send(message);
}
private static List<string> RetrieveMessages()
{
List<string> messages = new List<string>();
using (ExceptionQueue)
{
System.Messaging.Message[] queueMessages = ExceptionQueue.GetAllMessages();
foreach (System.Messaging.Message message in queueMessages)
{
message.Formatter = new XmlMessageFormatter(
new String[] { "System.String, mscorlib" });
string msg = message.Body.ToString();
messages.Add(msg);
}
}
return messages;
}
public static void Main(string[] args)
{
ExceptionMSMQ.PushMessage("my exception string");
}
}
An other widely used way to do that would also be to use out of the box loggers which already contains this functionality like Enterprise Library or NLog which provide easy interfaces to do that.
For retrieving messages I would recommend a separate windows service which would periodically read messages and process them. An good example on how to do that is given here: Windows service with timer
Update: Windows Service Example:
MSMQConsumerService.cs
public partial class MSMQConsumerService : ServiceBase
{
private System.Timers.Timer timer;
public MSMQConsumerService()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
this.timer = new System.Timers.Timer(30000D); // 30000 milliseconds = 30 seconds
this.timer.AutoReset = true;
this.timer.Elapsed += new System.Timers.ElapsedEventHandler(this.ProcessQueueMessages);
this.timer.Start();
}
protected override void OnStop()
{
this.timer.Stop();
this.timer = null;
}
private void ProcessQueueMessages(object sender, System.Timers.ElapsedEventArgs e)
{
MessageProcessor.StartProcessing();
}
}
and the MessageProcessor.cs
public class MessageProcessor
{
public static void StartProcessing()
{
List<string> messages = ExceptionMSMQ.RetrieveMessages();
foreach(string message in messages)
{
//write message in database
}
}
}
I have a simple wifi app. It is just scanning wifis and listing them. I figured out my ScanResult List is filling in another method but in OnPrepare/CreateOptionsMenu it is always null.
This method calls first when program starts I know that, but when i try to call it again with InvalidateOptionsMenu(); nothing changes. Here is my piec of code:
MainActivity:
public class MainActivity : Activity
{
public static Context context;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.Main);
Button wifiButton = FindViewById<Button>(Resource.Id.popupButton);
RegisterReceiver(new WiFiReceiver(), new IntentFilter(WifiManager.ScanResultsAvailableAction));
((WifiManager)GetSystemService(WifiService)).StartScan();
wifiButton.Click += (s, arg) => {
InvalidateOptionsMenu();
PopupMenu menu = new PopupMenu(this, wifiButton);
menu.Inflate(Resource.Menu.menu);
menu.Show();
};
}
public override bool OnCreateOptionsMenu(IMenu menu) {
WiFiReceiver wifiReceiver = new WiFiReceiver();
IList<ScanResult> availableWifis = wifiReceiver.GetWifiList();//This is always null
if (availableWifis != null) {
foreach (ScanResult token in availableWifis) {
menu.Add(token.Ssid);
}
}
return base.OnCreateOptionsMenu(menu);
}
}
WiFi Scanning this class:
class WiFiReceiver : BroadcastReceiver {
private IList<ScanResult> wifiList;
private string message;
public override async void OnReceive(Context context, Intent intent) {
MainActivity mainActivity = (MainActivity)context;
WifiManager wifiManager = (WifiManager)mainActivity.GetSystemService(Context.WifiService);
this.message = string.Join("\r\n", wifiManager.ScanResults
.Select(r => $"{r.Ssid} - {r.Level} dB"));
this.wifiList = wifiManager.ScanResults.ToList(); //This has connection informations
mainActivity.DisplayText(message);
await Task.Delay(TimeSpan.FromSeconds(1));
wifiManager.StartScan();
}
public IList<ScanResult> GetWifiList() {
return wifiList;
}
Below you can see a simplified version of my SignalR self hosted hub on a windows service:
public static class SubscriptionHandler
{
public static int PriceFeedMembersCount = 0;
}
public class PriceHub : Hub
{
public Task SubscribeToPriceFeed()
{
IHubContext context = GlobalHost.ConnectionManager.GetHubContext<PriceHub>();
if (SubscriptionHandler.PriceFeedMembersCount == 0)
{
context.Clients.All.updatePriceSubscriptionStatus(true);
}
SubscriptionHandler.PriceFeedMembersCount++;
return context.Groups.Add(Context.ConnectionId, "PriceFeed");
}
public Task UnsubscribeFromPriceFeed()
{
IHubContext context = GlobalHost.ConnectionManager.GetHubContext<PriceHub>();
SubscriptionHandler.PriceFeedMembersCount--;
if (SubscriptionHandler.PriceFeedMembersCount == 0)
{
context.Clients.All.updatePriceSubscriptionStatus(false);
}
return context.Groups.Remove(Context.ConnectionId, "PriceFeed");
}
public void NotifySubscribers(Price price)
{
IHubContext context = GlobalHost.ConnectionManager.GetHubContext<PriceHub>();
context.Clients.Group("PriceFeed").updatePrice(price);
}
}
And I have two types of clients for that hub: One of them is web applications and the other one is windows services. Here you can see a demo implementation for my windows service as a signalr client:
public partial class WinSer45 : ServiceBase
{
private HubConnection hubConnection;
private IHubProxy priceProxy;
private Timer timer = new Timer();
private bool hasSubscribers = false;
public WinSer45()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
timer.Interval = 1000; // saniyede bir
timer.Elapsed += timer_Elapsed;
timer.Enabled = true;
hubConnection = new HubConnection("http://localhost:8080/signalr", useDefaultUrl: false);
priceProxy = hubConnection.CreateHubProxy("PriceHub");
hubConnection.Start().Wait();
priceProxy.On<bool>("UpdatePriceSubscriptionStatus", hasSubscribers =>
{
this.hasSubscribers = hasSubscribers;
});
}
void timer_Elapsed(object sender, ElapsedEventArgs e)
{
if (hasSubscribers)
{
TestPrice testPrice = new TestPrice() { Id = 1, Buy = 1.2345, Sell = 9.8765, Symbol = "EURUSD" };
priceProxy.Invoke("NotifySubscribers", testPrice).Wait();
}
}
protected override void OnStop()
{
}
}
As you see I use the hasSubscribers flag to minimize the messages between hub and clients. And hasSubscribers flag is changed by SubscribeToPriceFeed and UnsubscribeFromPriceFeed methods.
If you look carefully you see the line below in SubscribeToPriceFeed:
context.Clients.All.updatePriceSubscriptionStatus(true);
I don't want to send the message to all clients but my client windows service. How can I store the connection Id of a specific client in my hub? If I can do that, I know I can send message to a specific connectionId as in the line below:
context.Clients.Client(connectionId).updatePriceSubscriptionStatus(true);
Thanks in advance,
pass source during connection
like this
hubConnection = new HubConnection("http://localhost:8080/signalr","source=windows",useDefaultUrl: false);
HUB
public override Task OnConnected()
{
var source= Context.QueryString['source'];
return base.OnConnected();
}
create a class which will hold the user with source
public class user {
public string ConnectionID {set;get;}
public string Source {set;get;}
}
declare a list in the hub
List<user> userList=new List<user>();
Then push the user during OnConnected
public override Task OnConnected()
{
var us=new user();
us.Source = Context.QueryString['source'];
us.ConnectionID=Context.ConnectionId;
userList.Add(us);
return base.OnConnected();
}
and during broadcast just filter it by source
var windowsUser=userList.Where(o=>o.Source == "windows").ToList(); // you'll get the windows user list