14.1. Requesting permissions

Geolocation requires an explicit request of permissions from the user. This check is usually done in the onCreate callback of the main activity.

The first block of code indicates whether we already have the permissions or need to request them:

if(isPermissionsGranted()){
	// we have permissions 
} else {
	requestLocationPermission()
}

In the code above, the functions are defined as follows:

private fun isPermissionsGranted() = ContextCompat.checkSelfPermission(
   this,
   Manifest.permission.ACCESS_FINE_LOCATION
) == PackageManager.PERMISSION_GRANTED

private fun requestLocationPermission() {
   if (ActivityCompat.shouldShowRequestPermissionRationale(this,
           Manifest.permission.ACCESS_FINE_LOCATION)) {
       Toast.makeText(this, "Go to settings", Toast.LENGTH_SHORT).show()
   } else {
       ActivityCompat.requestPermissions(this,
           arrayOf(Manifest.permission.ACCESS_FINE_LOCATION),
           0)
   }
}

Finally, if it has been necessary to request permissions and to receive the user’s response, we would do the following:

override fun onRequestPermissionsResult(
   requestCode: Int,
   permissions: Array<out String>,
   grantResults: IntArray
) {
   when(requestCode){
       0 -> if(grantResults.isNotEmpty() && grantResults[0]== PackageManager.PERMISSION_GRANTED){
          // user accepts permission
       }else{
           Toast.makeText(this, “To activate the location go to settings and accept the permissions”, Toast.LENGTH_SHORT).show()
       }
       else -> {}
   }
}