Wednesday, 9 February 2011

Get address from location using Geocoder

Geocoder is a class for handling geocoding and reverse geocoding. Geocoding is the process of transforming a street address or other description of a location into a (latitude, longitude) coordinate. Reverse geocoding is the process of transforming a (latitude, longitude) coordinate into a (partial) address. The amount of detail in a reverse geocoded location description may vary, for example one might contain the full street address of the closest building, while another might contain only a city name and postal code. The Geocoder class requires a backend service that is not included in the core android framework. The Geocoder query methods will return an empty list if there no backend service in the platform. Use the isPresent() method to determine whether a Geocoder implementation exists.

The getFromLocation(double latitude, double longitude, int maxResults) method returns an array of Addresses that are known to describe the area immediately surrounding the given latitude and longitude. The returned addresses will be localized for the locale provided to this class's constructor.

The returned values may be obtained by means of a network lookup. The results are a best guess and are not guaranteed to be meaningful or correct. It may be useful to call this method from a thread separate from your primary UI thread.

It's a exercise getting reversed address from a given location (LATITUDE and LONGITUDE), maxResults is set to one.

Get address from location using Geocoder

package com.exercise.AndroidFromLocation;

import java.io.IOException;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidFromLocation extends Activity {

double LATITUDE = 37.42233;
double LONGITUDE = -122.083;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView myLatitude = (TextView)findViewById(R.id.mylatitude);
TextView myLongitude = (TextView)findViewById(R.id.mylongitude);
TextView myAddress = (TextView)findViewById(R.id.myaddress);

myLatitude.setText("Latitude: " + String.valueOf(LATITUDE));
myLongitude.setText("Longitude: " + String.valueOf(LONGITUDE));

Geocoder geocoder = new Geocoder(this, Locale.ENGLISH);

try {
List<Address> addresses = geocoder.getFromLocation(LATITUDE, LONGITUDE, 1);

if(addresses != null) {
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder("Address:\n");
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress.append(returnedAddress.getAddressLine(i)).append("\n");
}
myAddress.setText(strReturnedAddress.toString());
}
else{
myAddress.setText("No Address returned!");
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
myAddress.setText("Canont get Address!");
}

}
}


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Location"
android:background="#505050"
/>
<TextView
android:id="@+id/mylatitude"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/mylongitude"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Address"
android:background="#505050"
/>
<TextView
android:id="@+id/myaddress"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>


Download the files.

Related Article:
- Get list of address from location using Geocoder

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