Tuesday, August 7, 2012

get latitude and longitude from android.location.Address

The result returned from Geocoder.getFromLocationName() is a List of android.location.Address object. To retrieve the latitude and longitude of the selected item's Address, getLatitude() and getLongitude() methods can be used.

Further work on last post, Display address from Geocoder.getFromLocationName() in a ListView. Implement listviewResultOnItemClickListener of OnItemClickListener to handle the item click event, and display the location (latitude and longitude) in Toast.

package com.AndroidgetFromLocationName;

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

import android.app.Activity;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidgetFromLocationNameActivity extends Activity {

 EditText searchText;
 Button searchButton;
 ListView listviewResult;
 
 Geocoder myGeocoder;
 final static int MAX_RESULT = 10;
 final static String DEFAULT_SEARCH = "谷歌";
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      searchText = (EditText)findViewById(R.id.searchtext);
      searchText.setText(DEFAULT_SEARCH);
   searchButton = (Button)findViewById(R.id.searchbutton);
   listviewResult = (ListView)findViewById(R.id.listviewresult);
   
   searchButton.setOnClickListener(searchButtonOnClickListener);
   
   myGeocoder = new Geocoder(this);
   
   //for API Level 9 or higher
   if (!Geocoder.isPresent()){
    Toast.makeText(AndroidgetFromLocationNameActivity.this,
     "Sorry! Geocoder service not Present.",
     Toast.LENGTH_LONG).show();
   }
   
   listviewResult.setOnItemClickListener(listviewResultOnItemClickListener);
  }

  OnItemClickListener listviewResultOnItemClickListener
  = new OnItemClickListener(){

  @Override
  public void onItemClick(AdapterView<?> parent, View view, int position,
    long id) {
   // TODO Auto-generated method stub
   
   double lat = ((Address)parent.getItemAtPosition(position)).getLatitude();
   double lon = ((Address)parent.getItemAtPosition(position)).getLongitude();
   String loc = "lat: " + lat + "\n" + "lon: " + lon;
   Toast.makeText(AndroidgetFromLocationNameActivity.this,
     loc,
     Toast.LENGTH_LONG).show();
  }
  
 };

  Button.OnClickListener searchButtonOnClickListener
  = new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   String searchString = searchText.getText().toString();
   searchFromLocationName(searchString);
  }};
  
 private void searchFromLocationName(String name){
  try {
   List<Address> result
   = myGeocoder.getFromLocationName(name, MAX_RESULT);
   
   if ((result == null)||(result.isEmpty())){
    Toast.makeText(AndroidgetFromLocationNameActivity.this,
      "No matches were found or there is no backend service!",
      Toast.LENGTH_LONG).show();
   }else{

    MyArrayAdapter adapter = new MyArrayAdapter(this,
          android.R.layout.simple_list_item_1, result);
    listviewResult.setAdapter(adapter);
    
    Toast.makeText(AndroidgetFromLocationNameActivity.this,
      "Finished!",
      Toast.LENGTH_LONG).show();
   }

   
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   Toast.makeText(AndroidgetFromLocationNameActivity.this,
     "The network is unavailable or any other I/O problem occurs!",
     Toast.LENGTH_LONG).show();
  }
 }
 
 public class MyArrayAdapter extends ArrayAdapter<Address> {
  Context mycontext;
  public MyArrayAdapter(Context context, int textViewResourceId,
    List<Address> objects) {
   super(context, textViewResourceId, objects);
   // TODO Auto-generated constructor stub
   mycontext = context;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   // TODO Auto-generated method stub
   
   int maxAddressLineIndex = getItem(position).getMaxAddressLineIndex();
   String addressLine = "";
   
   for (int j = 0; j <= maxAddressLineIndex; j++){
    addressLine += getItem(position).getAddressLine(j) + ",";
   }
   
   TextView rowAddress = new TextView(mycontext);
   rowAddress.setText(addressLine);
   
   return rowAddress;

  }

 }
 
}

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