AndroidLocation with Zoom Level Control, using SeekBar

Further works on last exercise, MapView to center on the current location from GPS. A SeekBar to change Zoom Level is implemented. Also add valid checking in Start-up Location, skip if invalid; to prevent from Unexpected Stop.



Modify main.xml

<?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"
  > 
 <LinearLayout
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  >
   <TextView
    android:id="@+id/longitude"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Longitude:"
  />
  <TextView
   android:id="@+id/latitude"
   android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Latitude:"
  />
   <SeekBar
   android:id="@+id/zoombar"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:max="20"
    android:progress="0"/>
 </LinearLayout>
 <com.google.android.maps.MapView
  android:id="@+id/mapview"
  android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:clickable="false"
  android:apiKey="-----Your Own API Key here-------------"
 />
</LinearLayout>

AndroidLocation.java

package com.AndroidLocation;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidLocation extends MapActivity {

 private LocationManager myLocationManager;
 private LocationListener myLocationListener;
 private TextView myLongitude, myLatitude;
 
 private MapView myMapView;
 private SeekBar myZoomBar;
 
 private MapController myMapController;

 private void CenterLocation(GeoPoint centerGeoPoint)
 {
  myMapController.animateTo(centerGeoPoint);
  
 
  myLongitude.setText("Longitude: "+
   String.valueOf((float)centerGeoPoint.getLongitudeE6()/1000000)
   );
  myLatitude.setText("Latitude: "+
   String.valueOf((float)centerGeoPoint.getLatitudeE6()/1000000)
   );
 };
 
 private void SetZoomLevel()
 {
  int myZoomLevel = myZoomBar.getProgress()+1;
  myMapController.setZoom(myZoomLevel);
  Toast.makeText(this,
    "Zoom Level : " + String.valueOf(myZoomLevel),
    Toast.LENGTH_LONG).show();
 };

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  myMapView = (MapView)findViewById(R.id.mapview);
  myLongitude = (TextView)findViewById(R.id.longitude);
  myLatitude = (TextView)findViewById(R.id.latitude);
  myZoomBar = (SeekBar)findViewById(R.id.zoombar);
  
  myMapView.setSatellite(true); //Set satellite view
  myMapController = myMapView.getController();
  SetZoomLevel();

  myLocationManager = (LocationManager)getSystemService(
    Context.LOCATION_SERVICE);

  myLocationListener = new MyLocationListener();

  myLocationManager.requestLocationUpdates(
    LocationManager.GPS_PROVIDER,
    0,
    0,
    myLocationListener);
  
  //Get the current location in start-up
  //check LastKnownLocation, if not valid, skip it.
  Location initLocation=
   myLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
  if(initLocation != null)
  {
   GeoPoint initGeoPoint = new GeoPoint(
     (int)(initLocation.getLatitude()*1000000),
     (int)(initLocation.getLongitude()*1000000));
   CenterLocation(initGeoPoint);
  }
  myZoomBar.setOnSeekBarChangeListener(myZoomBarOnSeekBarChangeListener);
 }
 
 private SeekBar.OnSeekBarChangeListener myZoomBarOnSeekBarChangeListener =
  new SeekBar.OnSeekBarChangeListener(){

   public void onProgressChanged(SeekBar seekBar, int progress,
     boolean fromUser) {
    // TODO Auto-generated method stub
    SetZoomLevel();
   }

   public void onStartTrackingTouch(SeekBar seekBar) {
    // TODO Auto-generated method stub
    
   }

   public void onStopTrackingTouch(SeekBar seekBar) {
    // TODO Auto-generated method stub
    
   }
  
 };

 private class MyLocationListener implements LocationListener{

  public void onLocationChanged(Location argLocation) {
   // TODO Auto-generated method stub
   GeoPoint myGeoPoint = new GeoPoint(
    (int)(argLocation.getLatitude()*1000000),
    (int)(argLocation.getLongitude()*1000000));
   
   CenterLocation(myGeoPoint);
  }

  public void onProviderDisabled(String provider) {
   // TODO Auto-generated method stub
  }

  public void onProviderEnabled(String provider) {
   // TODO Auto-generated method stub
  }

  public void onStatusChanged(String provider,
    int status, Bundle extras) {
   // TODO Auto-generated method stub
  }
 }

 @Override
 protected boolean isRouteDisplayed() {
  // TODO Auto-generated method stub
  return false;
 };
}

Download the files.