Using Geocoder to retrieve address based on Latitude and Longitude causes lag. Android

Question

I have a map activity which also has an EditText on top of it and I want to show the changing address in that EditText whenever there's a drag on the map. I am currently using Geocoder class to retrieve address based on the coordinates provided by the map. But this way is causing a lot of lag in the fluent dragging motion of the map. Is there a better way to retrieve address or a more efficient way to use Geocoder class? Right now, I have implemented the getAddress() method inside the OnCameraChangeListener event of my map. Here is the code.

mMap.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener() {
            @Override
            public void onCameraChange(CameraPosition cameraPosition) {
                double latitude=mMap.getCameraPosition().target.latitude;
                double longitude=mMap.getCameraPosition().target.longitude;
                String _Location="";
                Geocoder geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());
                try {
                    List<Address> listAddresses = geocoder.getFromLocation(latitude, longitude, 1);
                    if(null!=listAddresses&&listAddresses.size()>0){
                        _Location = listAddresses.get(0).getAddressLine(0);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                EditText addressTxt=(EditText) findViewById(R.id.search_address_txt);
                addressTxt.setText(_Location);
            }
        });

I have seen another app implemented where the address searched was at the end of the map drag and there was no lag in the map's motion.

score 1 · Accepted Answer · edited May 23 '17 at 11:48

The Geocoder$getFromLocation() is a blocking call, which means it will freeze the UI thread till the api returns the address. The only solution is to run this call on a background thread.

There are two ways you can achieve this:

Use Google recommended way - Using an Intent Service. You can find the details on how to here. Personally, I feel this is overkill and very complicated.
Use an AsyncTask. See this to get a general idea and implement according to your needs.

Also, if you are using Rx, you can start a new observable from the geocoder and observe on a different thread and subscribe on the main thread.

UPDATE: I pulled this code from one of my old projects, see if it helps.

AsyncGeocoderObject.java // object to pass to asynctask

public class AsyncGeocoderObject {

    public Location location; // location to get address from
    Geocoder geocoder; // the geocoder
    TextView textView; // textview to update text

    public AsyncGeocoderObject(Geocoder geocoder, Location location, TextView textView) {
        this.geocoder = geocoder;
        this.location = location;
        this.textView = textView;
    }
}

The AsyncTask implementation

public class AsyncGeocoder extends AsyncTask<AsyncGeocoderObject, Void, List<Address>> {

private TextView textView;

@Override
protected List<Address> doInBackground(AsyncGeocoderObject... asyncGeocoderObjects) {
    List<Address> addresses = null;
    AsyncGeocoderObject asyncGeocoderObject = asyncGeocoderObjects[0];
    textView = asyncGeocoderObject.textView;
    try {
        addresses = asyncGeocoderObject.geocoder.getFromLocation(asyncGeocoderObject.location.getLatitude(),
                asyncGeocoderObject.location.getLongitude(), 1);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return addresses;
}

@Override
protected void onPostExecute(List<Address> addresses) {
    Log.v("onPostExecute", "location: " + addresses);
    String address;
    if (addresses != null)
        address = addresses.get(0).getLocality() + ", " + addresses.get(0).getCountryName();
    else address = "Service unavailable.";
    textView.setText(address);
}
}

Calling the method when location changes:

new AsyncGeocoder().execute(new AsyncGeocoderObject(
                new Geocoder(this),
                location,
                locationTV
        ));

Hope this helps!

UPDATE 2:
Notes on how to immplement the above:

Create new class AsyncGeocoderObject and copy the contents
Create another class (can be a sub-class within the activity or in a different java file) AsyncGeocoder and copy the contents.
Now, say you want to get the users location in MainActivity and display the address in a textview, say locationTV. After instantiating the textview, create a new object of AsyncGeocoder and pass in the parameters. eg:
```
// in onCreate()
new AsyncGeocoder().execute(new AsyncGeocoderObject(
        new Geocoder(this), // the geocoder object to get address
        location, // location object, 
        locationTV // the textview to set address on
)); 
```
Also, if you dont have a location object, create on using the latitude and longitude you have. See this post for how to.

Hope this helps you!

Sorry for the late reply. Appreciate the help. But can you please guide me a little where to put that code? In the activity where i need to get the address? Or do i make a new java class? — Rehan Yousaf, Jul 19 '16 at 16:40
I wanted to use the LatLng so I changed the parameters in the code you provided accordingly. Thank you! Its working now. — Rehan Yousaf, Jul 19 '16 at 17:52

Using Geocoder to retrieve address based on Latitude and Longitude causes lag. Android

1 Answers1