Answers

• LoriLalonde CAInsider, University, Developer Group Leader ✭✭✭

  September 2015 edited September 2015

  Create a BaseActivity class which contains the implementation you want every activity to adopt, then ensure all your activities extend your BaseActivity.

  Also you can refactor your RunOnUiThread calls as follows:

  RunOnUiThread(() => 
                  {
                      alertDialog = builder.Create();
                      alertDialog.SetTitle("Welfare Alert");
                      alertDialog.SetMessage("Alert triggered");
                      alertDialog.SetButton("OK", (s, ev) =>
                                          {
                                              okbuttonpressed = true;
                                          });
                      alertDialog.Show();
                  }
              );
  

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• hobeau USMember ✭

  September 2015

  A good way to keep track of this is to create a central class to track what activity you are currently and also to run your timed thread in. Here's an example:

  `using System;
  using System.Threading.Tasks;
  using Android.App;
  using Android.Views;

  namespace XamarinAndroidForum
  {
  public static class App
  {
  // Keep track of what current activity you are on here
  public static Activity _currentActivity;
  private static Task _alertLoop;

      public static void RunAlertThread()
      {
                  // Keep track of thread to see if it's already running if it is just ignore
          if (_alertLoop == null || _alertLoop.Status != TaskStatus.Running)
          {
                              // Run as async task
              _alertLoop = Task.Run(async () =>
              {
                                      // If you want to cancel the task later you may want to put a 
                                      // variable in here to set to false
                  while (true)
                  {
                      var builder = new AlertDialog.Builder(_currentActivity);
                      builder.SetTitle("Welfare Alert");
                      builder.SetMessage("Alert Triggered");
  
                                              // Keep what runs on the UI thread to a minimum
                      _currentActivity.RunOnUiThread(() =>
                      {
                          try
                          {
                              builder.Show();
                          }
                                                  // If the current activity isn't set correctly it will throw a 
                                                      // WindowManagerBadTokenException
                          catch(WindowManagerBadTokenException ex1)
                          {
  
                          }
                          catch(Exception ex2)
                          {
  
                          }
                      });
  
                      // Wait for 1 minute (milliseconds)
                      await Task.Delay(60000);
                  }
              });
          }
      }
  }
  

  }`

  To start the thread, in your MainActivity you will need to add the following to your 'OnCreate' override method:

  App._currentActivity = this; App.RunAlertThread();

  and then add this to your override 'OnRestart' method:

  App._currentActivity = this;

  The reason for that is the OnCreate method doesn't fire if you navigate back to MainActivity with the back button. You will need to include App._currentActivity = this; in OnCreate override methods throughout your activities so that the thread knows what activity to alert on.

  Also, I would keep a minimal amount of code in your RunOnUiThread as this can bog down the UI and you want to run as much code externally from the UI thread as you can.

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• Fussbot GBMember ✭

  September 2015

  Thank you for your answers.

  @hobeau your example is great thanks, I have another time execute every 30 seconds that checks for the ok button clicked if not a welfare alert call and text are sent.

  How would I incorporate those into this code?

  private void OnTimedEvent(object source, System.Timers.ElapsedEventArgs e)
  {
  okbuttonpressed = false;
  Activity activity = this;
  Console.WriteLine ("Alert");
  Android.App.AlertDialog.Builder builder = new AlertDialog.Builder (activity);
  RunOnUiThread(() =>
  alertDialog = builder.Create ());
  RunOnUiThread(() =>
  alertDialog.SetTitle ("Welfare Alert"));
  RunOnUiThread(() =>
  alertDialog.SetMessage ("Alert triggered"));
  RunOnUiThread(() =>
  alertDialog.SetButton("OK", (s, ev) =>
  {
  okbuttonpressed = true;
  }));
  RunOnUiThread(() =>
  alertDialog.Show ());
  bTimer = new System.Timers.Timer();
  bTimer.Elapsed+=OnTimedEvent2;
  bTimer.Interval= 30000;
  bTimer.Enabled=true;
  }

      private void OnTimedEvent2(object source, System.Timers.ElapsedEventArgs e)
      {
          if (!okbuttonpressed) {
              contactInfo = DataController.emergencyDetails;
              var uri = Android.Net.Uri.Parse ("tel:" + contactInfo["phone"].ToString() + "");
              var intent = new Intent (Intent.ActionCall, uri);
              intent.SetPackage("com.android.phone");
              StartActivity (intent);
              SendMessage();
          }
      }
  
      protected void SendMessage() {
  
          String phoneNo = contactInfo["phone"].ToString();
          String message = "Emergency, I'm here: https://maps.google.com/maps?q=loc:" + DataController.currentlat + "," + DataController.currentlng + "&z=17";
  
          try {
              SmsManager smsManager = SmsManager.Default;
              smsManager.SendTextMessage(phoneNo, null, message, null, null);
              Console.WriteLine("Message Sent");
          } catch (Exception e) {
              Console.WriteLine ("Message Failed");
      }
      }
  

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