Ok Android, Broadcast My Location

Managing the data sources

1. SQLiteOpenHelper class
2. BaseColumns interface

2. BaseColumns interface

Capturing the location

Broadcasting the location

1. Table not found
   The first error that may raise in your application is, "table not found". Well, that is legit error in your application and is a cause that a table you may wanted to create initially when database was created, (table) was not created and now it cannot be created until you remove the previous database and re-execute the onCreate function.
   To solve it, on the development environment, you can delete the data and then re-execute the application. But remember to always create the tables, and define the schema in the database's onCreate function.
2. Providers not available
   Since our application depends on the location providers, we need to make sure that they are available before we start cap*turing the location from our application and to get notified about other changes in the location of the user. You can use manager and get the location services and providers.
   The following code for example, determines whether the provider for GPS is enabled or not:

   Code

   1. boolean isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
      
   You can get other providers in a similar manner. Since that is a boolean object, you can use it in a condition and work appropriately. You can also create a logic to show a dialog and open the settings if user needs to trigger the providers.
   Code
   1. if(!isGPSEnabled && !isNetworkEnabled) {
   2. showSettingsDialog();
   3. }
      
   This would trigger another function that prompts the user to activate the provider in settings. The function has the following structure:
   Code
   
   1. public void showSettingsDialog()
   2. {
   3. new AlertDialog.Builder(mContext).setTitle("Enable GPS").setMessage("Enable GPS in your settings for receiving active location details.").setNegativeButton("Cancel", null).setPositiveButton("Settings", new DialogInterface.OnClickListener()
   4. {@
   5. Override
   6. public void onClick(DialogInterface dialog, int which)
   7. {
   8. Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
   9. mContext.startActivity(intent);
   10. }
   11. }).create().show();
   12. }
       
   This would prompt the user to activate the location services. Just for the sake of this article, I can mimic the scenario and show you how it works. For example, we have an application that activates the location providers and gets the location from them.
   
   Figure 5- Android device showing the settings and location is enabled by default
   We can disable the location to see how our application would behave.
   
   Figure 6- Location is now turned off
   Now, we can trigger the capturing function in our application to see what happens. Firstly, consider we are having a condition that checks if the providers are enabled. If they are not, then the function displays an alert box, otherwise if that was not the case, then an exception may have been raised because providers are not available.
   When we click to enable the service, our location manager would tell us that providers are not enabled and thus our application prompts user to enable the services. Otherwise, cancel the operation.
   
   Figure 7- The android alert dialog, to prompt him to enable the location
   User can then enable the location in their settings, since they were disabled.
   Code
   1. Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
      
   The above intent would take the user to location settings by default, so that is the same thing other applications do which take you directly to the settings.
   
   Figure 8- Location turned off. User can turn it on to enable the providers
   GPS can then be seen to notify that the location providers are working and location can be captured by your application for users.
   
   Figure 9- GPS sign is shown in the system tray
   So, this explains how you should consider checking the paths that your application goes from and make sure you write the efficient application that takes care of most of the things for user.

3. Managing the resources

   The application shown above uses SMS resources, location resources, and battery. For this sake, since we just want to notify the users, you must consider keeping the time span large to save battery. Each time GPS engine is turned on, it would start consuming battery juice so you may want to make sure your application doesn't waste the juice.
   1. Minimum time
      Set it to like, 10 minutes at minimum. You do not want constant updates unless you are showing the GPS on screen.
   2. Minimum distance
      100 meters doesn't matter at all, so, this may be set as a minimum distance traveled.

1. LocationManager
2. LocationListener
3. PendingIntent
4. SmsManager
5. SQLiteOpenHelper
6. BaseColumns
7. And much more.