I have this code to set the Mainpage of my Application.
public async Task LoadMainPage()
{
try
{
signedin = Auth.IsUserSignedIn();
if (signedin)
registered = await Firestore.IsUserRegistered();
if (!signedin)
{
MainPage = new NavigationPage(new MainPage());
}
else if (signedin && !(registered))
{
MainPage = new NavigationPage(new RegistrationPage());
}
else if (signedin && (registered))
{
MainPage = new NavigationPage(new FlyoutPage1());
}
}
catch (Exception ex) { await App.Current.MainPage.DisplayAlert("Error", ex.Message, "OK"); }
}
I am calling this method from App.Xaml.cs Onstart method
protected override async void OnStart()
{
base.OnStart();
await LoadMainPage();
}
the problem is when the Application is launched the Mainpage fails to Load Properly.
it appears only when i tap the triple line icon on my phone wait for some time and tap the application again to launch it.
the code for Firestore.IsUserRegistered is as below
public async Task<bool> IsUserRegistered()
{
FirebaseFirestore collection = FirebaseFirestore.Instance;
string email = FirebaseAuth.Instance.CurrentUser.Email;
Android.Gms.Tasks.Task task = collection.Collection("User").WhereEqualTo("Email", email)
.Limit(1).Get().AddOnSuccessListener(this);
for (int i = 0; i < 25; i++)
{
await Task.Delay(100);
if (isregistered ) break;
}
return isregistered;
}
public void OnSuccess(Java.Lang.Object result)
{
var documents = (QuerySnapshot)result;
isregistered = !documents.IsEmpty;
}
You can add await LoadMainPage(); to OnResume() just like Splash Screen.
It said:
The startup work is performed asynchronously in OnResume. This is necessary so that the startup work does not slow down or delay the appearance of the launch screen. When the work has completed, SplashActivity will launch MainActivity and the user may begin interacting with the app.
Related
I am using xamarin forms for my app. I need to send local notification based on SQLite table for ios. I am using the following code:
AppDelegate.cs:
using System;
using Foundation;
using UIKit;
using Xamarin.Forms;
using Firebase.Database;
using Firebase.CloudMessaging;
using UserNotifications;
using Microsoft.AppCenter.Crashes;
using Plugin.Permissions;
using Plugin.Permissions.Abstractions;
using CoreTelephony;
using Firebase.Auth;
using System.Threading.Tasks;
using System.Collections.Generic;
namespace MyApp.iOS
{
[Register("AppDelegate")]
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate, IUNUserNotificationCenterDelegate, IMessagingDelegate
{
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();
AppDomain.CurrentDomain.UnhandledException += CurrentDomainOnUnhandledException;
Firebase.Core.App.Configure();
Database.DefaultInstance.PersistenceEnabled = true;
LoadApplication(new MyApp.App());
RegisterForRemoteNotifications();
Messaging.SharedInstance.Delegate = this;
if (UNUserNotificationCenter.Current != null)
{
UNUserNotificationCenter.Current.Delegate = new UserNotificationCenterDelegate();
}
if (UNUserNotificationCenter.Current != null)
{
UNUserNotificationCenter.Current.Delegate = new UserNotificationCenterDelegate();
}
Xamarin.FormsMaps.Init();
UIApplication.SharedApplication.IdleTimerDisabled = true;
UIApplication.SharedApplication.SetMinimumBackgroundFetchInterval(UIApplication.BackgroundFetchIntervalMinimum);
return base.FinishedLaunching(app, options);
}
public override bool ShouldRestoreApplicationState(UIApplication application, NSCoder coder)
{
return true;
}
private async System.Threading.Tasks.Task AcessPermissionsAsync()
{
try
{
await CrossPermissions.Current.RequestPermissionsAsync(Permission.Camera);
}
catch(Exception ex)
{
Crashes.TrackError(ex);
}
}
private void RegisterForRemoteNotifications()
{
if (UIDevice.CurrentDevice.CheckSystemVersion(10, 0))
{
UNUserNotificationCenter.Current.RemoveAllPendingNotificationRequests(); // To remove all pending notifications which are not delivered yet but scheduled.
UNUserNotificationCenter.Current.RemoveAllDeliveredNotifications(); // To remove all delivered notifications
}
else
{
UIApplication.SharedApplication.CancelAllLocalNotifications();
}
// Register your app for remote notifications.
if (UIDevice.CurrentDevice.CheckSystemVersion(10, 0))
{
// For iOS 10 display notification (sent via APNS)
UNUserNotificationCenter.Current.Delegate = this;
var authOptions = UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound;
UNUserNotificationCenter.Current.RequestAuthorization(authOptions, async (granted, error) =>
{
Console.WriteLine(granted);
await System.Threading.Tasks.Task.Delay(500);
await AcessPermissionsAsync();
});
}
else
{
// iOS 9 or before
var allNotificationTypes = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound;
var settings = UIUserNotificationSettings.GetSettingsForTypes(allNotificationTypes, null);
UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);
}
UIApplication.SharedApplication.RegisterForRemoteNotifications();
}
public override void DidEnterBackground(UIApplication uiApplication)
{
Messaging.SharedInstance.ShouldEstablishDirectChannel = false;
}
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
Messaging.SharedInstance.ApnsToken = deviceToken;
}
[Export("messaging:didReceiveRegistrationToken:")]
public void DidReceiveRegistrationToken(Messaging messaging, string fcmToken)
{
Xamarin.Forms.Application.Current.Properties["Fcmtocken"] = Messaging.SharedInstance.FcmToken ?? "";
Xamarin.Forms.Application.Current.SavePropertiesAsync();
System.Diagnostics.Debug.WriteLine($"######Token###### : {fcmToken}");
DeviceId.FCMTocken = fcmToken;
// TODO: If necessary send token to application server.
// Note: This callback is fired at each app startup and whenever a new token is generated.
}
public override void ReceivedRemoteNotification(UIApplication application, NSDictionary userInfo)
{
// If you are receiving a notification message while your app is in the background,
// this callback will not be fired till the user taps on the notification launching the application.
// TODO: Handle data of notification
// With swizzling disabled you must let Messaging know about the message, for Analytics
// Print full message.
Console.WriteLine(userInfo);
}
public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
{
try
{
Console.WriteLine(userInfo);
completionHandler(UIBackgroundFetchResult.NewData);
}
catch(Exception ex)
{
Crashes.TrackError(ex);
}
}
public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations(UIApplication application, UIWindow forWindow)
{
switch (Device.Idiom)
{
case TargetIdiom.Phone:
return UIInterfaceOrientationMask.Portrait;
case TargetIdiom.Tablet:
return UIInterfaceOrientationMask.Landscape;
default:
return UIInterfaceOrientationMask.Portrait;
}
}
private void CurrentDomainOnUnhandledException(object sender, UnhandledExceptionEventArgs unhandledExceptionEventArgs)
{
var newExc = new Exception("CurrentDomainOnUnhandledException", unhandledExceptionEventArgs.ExceptionObject as Exception);
ExceptionFileWriter.ToLogUnhandledException(newExc);
}
public void DidRefreshRegistrationToken(Messaging messaging, string fcmToken)
{
Xamarin.Forms.Application.Current.Properties["Fcmtocken"] = Messaging.SharedInstance.FcmToken ?? "";
Xamarin.Forms.Application.Current.SavePropertiesAsync();
System.Diagnostics.Debug.WriteLine($"######Token###### : {fcmToken}");
DeviceId.FCMTocken = fcmToken;
}
public override void PerformFetch(UIApplication application, Action<UIBackgroundFetchResult> completionHandler)
{
try
{
var baseService = new DatabaseServices<object, object>();
baseService.NotificationAssetTrip();
}
catch(Exception ex)
{
Logs.LogCreate("PerformFetch:Exception: " + ex.Message.ToString());
}
completionHandler(UIBackgroundFetchResult.NewData);
}
}
}
UserNotificationCenterDelegate.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Foundation;
using iAd;
using ObjCRuntime;
using UIKit;
using UserNotifications;
namespace MyApp.iOS
{
public class UserNotificationCenterDelegate : UNUserNotificationCenterDelegate
{
private DBService dataBase;
#region Constructors
public UserNotificationCenterDelegate()
{
UNUserNotificationCenter.Current.Delegate = this;
}
#endregion
#region Override Methods
public override void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
{
completionHandler.DynamicInvoke(UNNotificationPresentationOptions.Alert);
}
#endregion
}
}
App.xaml.cs:
private void SendNotificationTripAsset(int tripid)
{
//Forexample i have table with columns like title,subtitle,message means, i give like this
var content = new UserNotifications.UNMutableNotificationContent()
{
Title = title,
Subtitle = subtitle,
Body = message,
Badge = 1
};
var request = UserNotifications.UNNotificationRequest.FromIdentifier(list.TripID.ToString(), content, null);
UserNotifications.UNUserNotificationCenter.Current.AddNotificationRequest(request, (err) =>
{
if (err != null)
{
throw new Exception($"Failed to schedule notification: {err}");
}
});
}
But the notification is not trigged after app is killed(terminated). Can anyone please help me to resolve this issue.
To send a local notification when app is killed, you have to specify the time when should the local notification been sent. In your code, when you create the request, set a proper NNotificationTrigger :
NNotificationTrigger trigger = UNTimeIntervalNotificationTrigger.CreateTrigger(3, false);
var request = UserNotifications.UNNotificationRequest.FromIdentifier(list.TripID.ToString(), content, trigger );
That means this notification will be fired after 3 seconds. You can change the time to whatever you want.
Code will not execute when your app is killed, so if you don't know the specific time to fire the notification or it fires randomly, you should use a remote notification.
I have xamarin.forms app contains a listview which will load values from Rest API.Which is working fine.I have button just above the listview.When I click on the button, the listview API call will be placed again and the listview should update. But stuck at this update part.I am not using MVVM pattern.The listview listing portion is an async Task.I am calling the async task again when the button click, but App gets crash. Is it due to calling the async task again from button click? Any help is appreciated.
Here is My code.
namespace app
{
public partial class List : ContentPage
{
PendingWeekRange pendingWeekRange = new PendingWeekRange();
public TimeSheetList()
{
InitializeComponent();
Task.Run(async () =>
{
await LoadScreenItems();
});
}
async Task LoadScreenItems()
{
await Task.Run(async () => {
try
{
// Doing some stuff
await loadTimeSheetList();
}
catch (Exception)
{
}
});
}
async Task loadTimeSheetList()
{
await Task.Run(() => { + string postdataForPendingList = "{\"date\":\"" + "1" + "\"}";
APICall callForAPICallResult = new APICall("/API/ListMobile/ListForApproval", postdataForList, loadingIndicator);
try
{
List<ListData> resultObjForPendingTimeSheetList = callForAPICallResult<List<ListData>>();
if (resultObjForPendingTimeSheetList != null)
{
TimesheetList.ItemsSource = resultObjForPendingTimeSheetList;
screenStackLayout.VerticalOptions = LayoutOptions.FillAndExpand;
TimesheetList.IsVisible = true;
}
else
{
}
}
catch (Exception)
{
}
});
}
async void Button_Tapped(object sender, EventArgs e)
{
try
{
// Calling my listview again. After calling app gets crash
Task.Run(async () => await loadTimeSheetList());
}
catch (Exception ex) { }
}
}
}
A few things before getting to the problem. You've got async/await all wrong, go though Async Programming
Task.Run runs the passed action on a different thread, if you make changes to UI elements on this thread, your app will definitely(take my word) crash.
If you want to make async call at page launch, make use of OnAppearing method (if you only want to call once, maintain a flag)
Do not change the ItemsSource of a list view frequently, just clear and add items to it.
namespace app
{
public partial class List : ContentPage
{
PendingWeekRange pendingWeekRange = new PendingWeekRange();
private ObservableCollection<ListData> TimesheetObservableCollection = new ObservableCollection<ListData>();
public TimeSheetList()
{
InitializeComponent();
TimesheetList.ItemsSource = TimesheetObservableCollection;
}
protected override async OnAppearing()
{
// flag for first launch?
await LoadScreenItems();
}
async Task LoadScreenItems()
{
try
{
// Doing some stuff
TimesheetObservableCollection.Clear();
TimesheetObservableCollection.AddRange(await GetTimeSheetList());
}
catch (Exception)
{
//handle exception
}
}
async Task<List<ListData>> GetTimeSheetList()
{
string postdataForPendingList = "{\"date\":\"" + "1" + "\"}";
APICall callForAPICallResult = new APICall("/API/ListMobile/ListForApproval", postdataForList, loadingIndicator);
try
{
return callForAPICallResult<List<ListData>>();
}
catch (Exception)
{
// handle exception
}
}
async void Button_Tapped(object sender, EventArgs e)
{
try
{
// Calling my listview again. After calling app gets crash
TimesheetObservableCollection.Clear();
TimesheetObservableCollection.AddRange(await GetTimeSheetList());
}
catch (Exception ex) { }
}
}
}
#Androdevil,
Update your loadTimeSheetList with this,
async Task loadTimeSheetList()
{
try
{
// I am calling my API for Listview here.
List<TimeSheetListData> resultObjForPendingTimeSheetList = await callForPendingTimeSheetList.APICallResult<List<TimeSheetListData>>();
if (resultObjForPendingTimeSheetList != null)
{
TimesheetList.ItemsSource = resultObjForPendingTimeSheetList;
screenStackLayout.VerticalOptions = LayoutOptions.FillAndExpand;
TimesheetList.IsVisible = true;
}
else
{
}
}
catch (Exception)
{
}
}
I completed receiving test notification from FCM console. Now I am trying to open a page when tapping the notification. Any ideas about how to achieve this? I have searched the internet but can't find a working solution. I am also able to send the notification through the postman.
I handle the notification tapping in following way. The page loading is handled in App.xaml.cs.
On OnCreate():
//Background or killed mode
if (Intent.Extras != null)
{
foreach (var key in Intent.Extras.KeySet())
{
var value = Intent.Extras.GetString(key);
if (key == "webContentList")
{
if (value?.Length > 0)
{
isNotification = true;
LoadApplication(new App(domainname, value));
}
}
}
}
//Foreground mode
if (FirebaseNotificationService.webContentList.ToString() != "")
{
isNotification = true;
LoadApplication(new App(domainname, FirebaseNotificationService.webContentList.ToString()));
FirebaseNotificationService.webContentList = "";
}
//Normal loading
if (!isNotification)
{
LoadApplication(new App(domainname, string.Empty));
}
On FirebaseNotificationService:
[Service]
[IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
public class FirebaseNotificationService : FirebaseMessagingService
{
public static string webContentList = "";
public override void OnMessageReceived(RemoteMessage message)
{
base.OnMessageReceived(message);
webContentList = message.Data["webContentList"];
try
{
SendNotificatios(message.GetNotification().Body, message.GetNotification().Title);
}
catch (Exception ex)
{
Console.WriteLine("Error:>>" + ex);
}
}
public void SendNotificatios(string body, string Header)
{
if (Build.VERSION.SdkInt < BuildVersionCodes.O)
{
var intent = new Intent(this, typeof(MainActivity));
intent.AddFlags(ActivityFlags.ClearTop);
var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);
var notificationBuilder = new Android.App.Notification.Builder(this, Utils.CHANNEL_ID)
.SetContentTitle(Header)
.SetSmallIcon(Resource.Drawable.icon)
.SetContentText(body)
.SetAutoCancel(true)
.SetContentIntent(pendingIntent);
var notificationManager = NotificationManager.FromContext(this);
notificationManager.Notify(0, notificationBuilder.Build());
}
else
{
var intent = new Intent(this, typeof(MainActivity));
intent.AddFlags(ActivityFlags.ClearTop);
var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);
var notificationBuilder = new Android.App.Notification.Builder(this, Utils.CHANNEL_ID)
.SetContentTitle(Header)
.SetSmallIcon(Resource.Drawable.icon)
.SetContentText(body)
.SetAutoCancel(true)
.SetContentIntent(pendingIntent)
.SetChannelId(Utils.CHANNEL_ID);
if (Build.VERSION.SdkInt < BuildVersionCodes.O)
{
return;
}
var channel = new NotificationChannel(Utils.CHANNEL_ID, "FCM Notifications", NotificationImportance.High)
{
Description = "Firebase Cloud Messages appear in this channel"
};
var notificationManager = (NotificationManager)GetSystemService(NotificationService);
notificationManager.CreateNotificationChannel(channel);
notificationManager.Notify(0, notificationBuilder.Build());
}
}
I don't know what's your actual Firebase implementation, but this might help you.
There is a nice package for Firebase in Xamarin Forms that we use in our production App made by CrossGeeks team. Its working great and has all handlers for your needs. This works with iOS and Android and you don't need to write platform specific code, only configuration and some code in AppDelegate.cs and MainActivity.cs
https://github.com/CrossGeeks/FirebasePushNotificationPlugin/blob/master/docs/FirebaseNotifications.md#notification-events
I wrote a simple PushNotificationService that processes automatic refresh and/or pushes new pages considering push notif data.
When app is closed and user clicks on the notification, I store the push notif data using Akavache.
CrossFirebasePushNotification.Current.OnNotificationOpened += async (s, p) =>
{
if (App.AppBeenResumed)
{
await BlobCache.UserAccount.InsertObject("pushNotifData", p.Data);
}
else
{
await ProcessReceivedPushNotification(p.Data);
}
};
And on the landing page of the app, I check if there is an existing push notif data in the OnAppearing method of the page.
protected override void OnAppearing()
{
base.OnAppearing();
App.AppBeenResumed = false;
HandlePushNotificationIfExists();
}
private async void HandlePushNotificationIfExists()
{
IDictionary<string, object> pushNotifData;
try
{
pushNotifData = await BlobCache.UserAccount.GetObject<IDictionary<string, object>>("pushNotifData");
}
catch (KeyNotFoundException)
{
pushNotifData = null;
}
if (pushNotifData == null) return;
await BlobCache.UserAccount.InvalidateAllObjects<IDictionary<string, object>>();
await PushNotificationService.ProcessReceivedPushNotification(pushNotifData);
}
In the ProcessReceivedPushNotification you can do whatever you want ... push directly the page or whatever... call another service that will do the job of pushing a new page and some business process.
Note that App.AppBeenResumed is a static bool to determine if App has been started or resumed to handle correctly the process of treatment of the push notif (process it instant or store it in blobcache to treat it later when landing page is Appearing).
In MainActivity.cs :
protected override void OnCreate(Bundle bundle)
{
...
LoadApplication(new App(true));
}
In the App.cs :
public App(bool beenResumedOrStarted)
{
...
AppBeenResumed = beenResumedOrStarted;
...
}
protected override void OnResume()
{
AppBeenResumed = false;
}
protected override void OnSleep()
{
//iOS states are not the same so always false when device is iOS
AppBeenResumed = Device.RuntimePlatform != Device.iOS;
}
I am creating a chat application with Firebase and after creating it I am facing the issue that it is too slow. When a message is sent it will go to the server first and then it will show in the message list.
Can I save chat locally or can I show message on my thread before saving on db?
Here is my chat page:
namespace XamarinChatApp.View
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class ChatPage : ContentPage
{
DBFire db = new DBFire();
Room rm = new Room();
public ChatPage()
{
InitializeComponent();
MessagingCenter.Subscribe<RoomPage, Room>(this, "RoomProp", (page, data) =>
{
rm = data;
_lstChat.BindingContext = db.subChat(data.Key);
MessagingCenter.Unsubscribe<RoomPage, Room>(this, "RoomProp");
});
}
async void Handle_Clicked(object sender, System.EventArgs e)
{
// firsth chat object
//room name 1---okey
var chatOBJ = new Chat { UserMessage = _etMessage.Text, UserName = User.UserName };
_etMessage.Text = "";
await db.saveMessage(chatOBJ, rm.Key);
}
async void Upload_Photo(object sender, System.EventArgs e)
{
// firsth chat object
//room name 1---okey
await CrossMedia.Current.Initialize();
var imgData = await CrossMedia.Current.PickPhotoAsync(new Plugin.Media.Abstractions.PickMediaOptions());
await db.saveImage(imgData.GetStream());
// _img1.Source = ImageSource.FromStream(imgData.GetStream);
}
}
}
I have a requirement for my xamarin cross platform application that as soon as app start up .QR Scanner set in to read the code. on completing scanning a beep will be ring up.and app again ready for next scanning how can i get this done. what i have done is on button click scanner start, its read code, then i have to press button again to start it again.
public HomePage()
{
Button scanBtn = new Button
{
Text = "Scan Barcode",
HorizontalOptions = LayoutOptions.FillAndExpand,
};
scanBtn.Clicked += async (sender, args) =>
{
var scanResult = await Acr.BarCodes.BarCodes.Instance.Read();
if (!scanResult.Success)
{
await this.DisplayAlert("Alert ! ", "Sorry ! \n Failed to read the Barcode !", "OK");
}
else
{
var endpoint = new EndpointAddress("http://192.168.15.33/SMS/WebServices/SMSService.svc");
var binding = new BasicHttpBinding
{
Name = "basicHttpBinding",
MaxBufferSize = 2147483647,
MaxReceivedMessageSize = 2147483647
};
TimeSpan timeout = new TimeSpan(0, 0, 30);
binding.SendTimeout = timeout;
binding.OpenTimeout = timeout;
binding.ReceiveTimeout = timeout;
_client = new SMSServiceClient(binding, endpoint);
_client.ValidateStudentAsync("123-admin");
_client.ValidateStudentCompleted += _client_ValidateStudentCompleted; ;
// await this.DisplayAlert("Scan Successful !", String.Format("Barcode Format : {0} \n Barcode Value : {1}", scanResult.Format, scanResult.Code), "OK");
}
};
Content = new StackLayout
{
Children = {
scanBtn
}
};
}
and in app.cs
public class App : Application
{
public App()
{
// The root page of your application
MainPage = new HomePage();
}
protected override void OnStart()
{
MainPage = new HomePage();
}
protected override void OnSleep()
{
MainPage = new HomePage();
}
protected override void OnResume()
{
MainPage = new HomePage();
}
}
You can use ZXing.Net.Mobile for Forms to read QR codes. To initialize this plugin you should call method to init into each project (Android, iOS, UWP) like this:
For Android in MainActivity.cs class call:
ZXing.Net.Mobile.Forms.Droid.Platform.Init();
For iOS in AppDeletage.cs class call
ZXing.Net.Mobile.Forms.iOS.Platform.Init();
And finally to read QR Codes:
private async void Scan() {
var scanPage = new ZXingScannerPage();
scanPage.OnScanResult += (result) => {
// Stop scanning
scanPage.IsScanning = false;
// Pop the page and show the result
Device.BeginInvokeOnMainThread( async () => {
await Navigation.PopAsync();
await DisplayAlert("Scanned Barcode", result.Text, "OK");
});
};
// Navigate to our scanner page
await Navigation.PushAsync(scanPage);
}