Exercise AndroidMapper, Android Application using MapView

In the previous exercises, the MapView track the GPS and center on it repeatly. In this exercise, AndroidMapper, it will not track on GPS. Instead, there are three options to center in starting of the MapView.
- Default: Start ViewMap without any center location.
- GPS: It's the current GPS (which will be track before ViewMap start). If no valid GPS, this option will be disable.
- Location: User input location. If no location input, this option will be disable.



After ViewMap loaded, user can move the Map, Zoom-in/out using MapView's BuiltInZoomControls.



This application is not yet finished, more feature (or bug fixed) will be added in the furture.

Create a Android Application named, AndroidMapper.
Package Name: com.AndroidMapper
Target Google Platform 2.0 with Google APIs.

Modify main.xml to have the UI as seen in the picture.

<?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"
/>
<RadioGroup
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<RadioButton
android:id="@+id/option_default"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Default Location" />
<RadioButton
android:id="@+id/option_gps"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="GPS:" />
<RadioButton
android:id="@+id/option_location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Location:" />
</RadioGroup>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="latitude"
/>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/latitude"
android:inputType="numberDecimal"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="longitude"
/>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/longitude"
android:inputType="numberDecimal"
/>
<Button
android:id="@+id/loadmap"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Load Map"
/>
</LinearLayout>

Modify AndroidMapper.java

package com.AndroidMapper;

import com.google.android.maps.GeoPoint;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;

public class AndroidMapper extends Activity {

private LocationManager myLocationManager;
private LocationListener myLocationListener;
private GeoPoint GeoPoint_GPS, GeoPoint_Location;

RadioButton myoption_default, myoption_gps, myoption_location;
EditText mylatitude, mylongitude;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  loadMenu();
  validGPS();
  validLocation();

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

  myLocationListener = new MyLocationListener();

  myLocationManager.requestLocationUpdates(
       LocationManager.GPS_PROVIDER,
       0,
       0,
       myLocationListener);
}

private void loadMenu()
{
setContentView(R.layout.main);
myoption_default = (RadioButton)findViewById(R.id.option_default);
myoption_gps = (RadioButton)findViewById(R.id.option_gps);
myoption_location = (RadioButton)findViewById(R.id.option_location);
mylatitude = (EditText)findViewById(R.id.latitude);
mylongitude = (EditText)findViewById(R.id.longitude);

mylatitude.setOnKeyListener(locationOnKeyListener);
mylongitude.setOnKeyListener(locationOnKeyListener);

Button myLoadMapButton = (Button)findViewById(R.id.loadmap);
myLoadMapButton.setOnClickListener(myLoadMapButtonOnClickListener);
}

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

  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   if(myoption_default.isChecked()){
    OpenIntentAndroidMapView(null);
   }
   else if(myoption_gps.isChecked()){
    OpenIntentAndroidMapView(GeoPoint_GPS);
   }
   else if(myoption_location.isChecked()){
    OpenIntentAndroidMapView(GeoPoint_Location);
   }
   else{
    OpenMissingOptionDialog();
   }
   
  }

};

private void OpenIntentAndroidMapView(GeoPoint startLocation)
{
Intent intent = new Intent();
  intent.setClass(AndroidMapper.this, AndroidMapView.class);

  Bundle bundle = new Bundle();

  if (startLocation == null)
  {
   bundle.putInt("Mode", 0);
  }
  else
  {
   bundle.putInt("Mode", 1);
   bundle.putInt("Longitude", startLocation.getLongitudeE6());
   bundle.putInt("Latitude", startLocation.getLatitudeE6());
  }

  intent.putExtras(bundle);
startActivityForResult(intent, 0);
}

private void OpenMissingOptionDialog()
{
 new AlertDialog.Builder(this)
 .setTitle("missing selection")
 .setMessage("Please select one of the option")
 .setPositiveButton("OK",
  new DialogInterface.OnClickListener()
  {
   public void onClick(DialogInterface dialoginterface, int i)
    {}
  })
 .show();
}

EditText.OnKeyListener locationOnKeyListener =
new EditText.OnKeyListener(){

  @Override
  public boolean onKey(View v, int keyCode, KeyEvent event) {
   // TODO Auto-generated method stub
   validLocation();
   return false;
  }

};

private void validGPS()
{
GeoPoint_GPS = loadGPS();
if (GeoPoint_GPS==null)
{
 myoption_gps.setClickable(false);
}
else
{
 myoption_gps.setText("GPS: (" +
   String.valueOf((float)GeoPoint_GPS.getLatitudeE6()/1000000) +" : " +
   String.valueOf((float)GeoPoint_GPS.getLongitudeE6()/1000000) +")");
 myoption_gps.setClickable(true);
}
}

private void validLocation()
{
/*
Toast.makeText(AndroidMapper.this,
  mylatitude.getText().toString(),
  Toast.LENGTH_LONG).show();*/
if (mylatitude.getText().toString().equals("") || mylongitude.getText().toString().equals(""))
{

 myoption_location.setText("Location: ");
 myoption_location.setClickable(false);
 myoption_location.setChecked(false);
}
else
{
 float locationLatitude = Float.parseFloat(mylatitude.getText().toString());
 float locationLongitude = Float.parseFloat(mylongitude.getText().toString());

 myoption_location.setText("Location: (" +
   String.valueOf(locationLatitude) +" : " +
   String.valueOf(locationLongitude) +")");
 myoption_location.setClickable(true);
 myoption_location.setChecked(true);

 GeoPoint_Location = new GeoPoint(
          (int)(locationLatitude*1000000),
          (int)(locationLongitude*1000000));
}
}

private GeoPoint loadGPS()
{
//Get the current location from GPS
myLocationManager = (LocationManager)getSystemService(
     Context.LOCATION_SERVICE);
Location initLocation=myLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(initLocation != null)
  {
   return (
     new GeoPoint(
          (int)(initLocation.getLatitude()*1000000),
          (int)(initLocation.getLongitude()*1000000)));
  }
else
 return null;
}

private class MyLocationListener implements LocationListener{

 @Override
 public void onLocationChanged(Location location) {
  // TODO Auto-generated method stub
  GeoPoint_GPS = new GeoPoint(
        (int)(location.getLatitude()*1000000),
        (int)(location.getLongitude()*1000000));
  myoption_gps.setText("GPS: (" +
   String.valueOf((float)GeoPoint_GPS.getLatitudeE6()/1000000) +" : " +
   String.valueOf((float)GeoPoint_GPS.getLongitudeE6()/1000000) +")");
 myoption_gps.setClickable(true);
 }

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

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

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

}
}

Modify mymapview.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="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
 <CheckBox
  android:id="@+id/satellite"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text=" Satellite "
 />
 </LinearLayout>
 <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:"
  />
 </LinearLayout>
</LinearLayout>
<com.google.android.maps.MapView
 android:id="@+id/mapview"
 android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:clickable="true"
 android:apiKey="-----Your Own API Key here-------------"
/>
</LinearLayout>

You have to Obtaining a Maps API Key, and insert into the field "apikey"

Modify AndroidMapView.java

package com.AndroidMapper;

import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.TextView;

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

public class AndroidMapView extends MapActivity {

 private TextView myLongitude, myLatitude;
 private CheckBox mySatellite;

 private MapView myMapView;
 private MapController myMapController;

 private void SetSatellite()
 {
  myMapView.setSatellite(mySatellite.isChecked());
 };

@Override
protected void onCreate(Bundle icicle) {
 // TODO Auto-generated method stub
 super.onCreate(icicle);
 setContentView(R.layout.mymapview);

 Bundle bundle = this.getIntent().getExtras();
  int Mode = bundle.getInt("Mode");

 myMapView = (MapView)findViewById(R.id.mapview);
 myMapController = myMapView.getController();
 myMapView.setBuiltInZoomControls(true);

 myLongitude = (TextView)findViewById(R.id.longitude);
 myLatitude = (TextView)findViewById(R.id.latitude);
 mySatellite = (CheckBox)findViewById(R.id.satellite);
 mySatellite.setOnClickListener(mySatelliteOnClickListener);

 SetSatellite();


 if(Mode == 1)
 {
  int intLatitude = bundle.getInt("Latitude");
  int intLongitude = bundle.getInt("Longitude");
  GeoPoint initGeoPoint = new GeoPoint(intLatitude, intLongitude);
  CenterLocation(initGeoPoint);
 }
 
 
}



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

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 CheckBox.OnClickListener mySatelliteOnClickListener =
   new CheckBox.OnClickListener(){

    public void onClick(View v) {
     // TODO Auto-generated method stub
     SetSatellite();
    }
};

}

Also modify AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.AndroidMapper"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
  <activity android:name=".AndroidMapper"
            android:label="@string/app_name">
      <intent-filter>
          <action android:name="android.intent.action.MAIN" />
          <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
  </activity>
  <activity android:name=".AndroidMapView">
   </activity>
<uses-library android:name="com.google.android.maps" />
</application>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-sdk android:minSdkVersion="5" />

</manifest>

Download the files.

Check empty of EditText

To check if the content of a EditText is empty or not, the method equals() can be used.

if (EditText.getText().toString().equals(""))
{
//Do if the EditText is empty
}
else
{
//Do if the EditText is not empty
}

Where EditText is the View of the EditText.

RadioGroup and RadioButton

In this exercise, RadioGroup and RadioButton will be described.



A radio button is a two-states button that can be either checked or unchecked. When the radio button is unchecked, the user can press or click it to check it. A radio button cannot be unchecked by the user once checked.

Radio buttons are normally used together in a RadioGroup. When several radio buttons live inside a radio group, checking one radio button unchecks all the others.

RadioGroup is used to create a multiple-exclusion scope for a set of radio buttons. Checking one radio button that belongs to a radio group unchecks any previously checked radio button within the same group.

Intially, all of the radio buttons are unchecked. While it is not possible to uncheck a particular radio button, the radio group can be cleared to remove the checked state.

main.xml with three RadioButton inside a RadioGroup.

<?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"
  >
 <RadioGroup
  android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical">
   <RadioButton
    android:id="@+id/option1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Option 1" />
   <RadioButton
    android:id="@+id/option2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Option 2" />
   <RadioButton
    android:id="@+id/option3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Option 3" />
 </RadioGroup>
</LinearLayout>

AndroidRadioGroup.java

package com.exercise.AndroidRadioGroup;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.RadioButton;
import android.widget.Toast;

public class AndroidRadioGroup extends Activity {
 
 RadioButton myOption1, myOption2, myOption3;
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      myOption1 = (RadioButton)findViewById(R.id.option1);
      myOption2 = (RadioButton)findViewById(R.id.option2);
      myOption3 = (RadioButton)findViewById(R.id.option3);
      myOption1.setOnClickListener(myOptionOnClickListener);
      myOption2.setOnClickListener(myOptionOnClickListener);
      myOption3.setOnClickListener(myOptionOnClickListener);
      myOption1.setChecked(true);
  }

  RadioButton.OnClickListener myOptionOnClickListener =
   new RadioButton.OnClickListener()
  {

  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   Toast.makeText(AndroidRadioGroup.this,
     "Option 1 : " + myOption1.isChecked() + "\n"+
     "Option 2 : " + myOption2.isChecked() + "\n" +
     "Option 3 : " + myOption3.isChecked(),
     Toast.LENGTH_LONG).show();

  }
   
   
  };
}

Download the files.

setBuiltInZoomControls on MapView

If you read the article Hello, MapView from Android, ZoomControls widget is suggested for zooming in and out of a View. MapView can automatically hook one for us by requesting it with the getZoomControls() method. But...actually it is now deprecated.

Instead of ZoomControls, MapView.setBuiltInZoomControls(true) can be used to add zoom mechanism on MapView.



Modify from previous article, AndroidLocation: with a CheckBox to toggle MapView.setSatellite().

Modify main.xml to remove SeekBar from the previous layout, and change android:clickable of com.google.android.maps.MapView to "true".

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="horizontal"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  >
  <LinearLayout
  android:orientation="vertical"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  >
   <CheckBox
    android:id="@+id/satellite"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text=" Satellite "
   />
  </LinearLayout>
  <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:"
   />
  </LinearLayout>
 </LinearLayout>
 <com.google.android.maps.MapView
  android:id="@+id/mapview"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:clickable="true"
  android:apiKey="-----Your Own API Key here-------------"
 />
</LinearLayout>

Modify AndroidLocation.java, remove all myZoomBar related code, and add the code
myMapView.setBuiltInZoomControls(true);

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.view.View;
import android.widget.CheckBox;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidLocation extends MapActivity {

 private LocationManager myLocationManager;
 private LocationListener myLocationListener;
 private TextView myLongitude, myLatitude;
 private CheckBox mySatellite;
 
 private MapView myMapView;
 
 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 SetSatellite()
 {
  myMapView.setSatellite(mySatellite.isChecked());
 };

 /** 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);
  
  myMapView.setBuiltInZoomControls(true);

  
  myLongitude = (TextView)findViewById(R.id.longitude);
  myLatitude = (TextView)findViewById(R.id.latitude);
  mySatellite = (CheckBox)findViewById(R.id.satellite);
  
  SetSatellite();
  myMapController = myMapView.getController();

  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);
  }
  mySatellite.setOnClickListener(mySatelliteOnClickListener);
 }
 
 private CheckBox.OnClickListener mySatelliteOnClickListener =
  new CheckBox.OnClickListener(){

   public void onClick(View v) {
    // TODO Auto-generated method stub
    SetSatellite();
   }
  
 };
 

 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.

AndroidLocation: with a CheckBox to toggle MapView.setSatellite()

Modify previous exercise AndroidLocation with Zoom Level Control, using SeekBar, to have a CheckBox used to toggle "satellite" mode.



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="horizontal"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  >
  <LinearLayout
  android:orientation="vertical"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  >
   <CheckBox
   android:id="@+id/satellite"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text=" Satellite "
   />
 </LinearLayout>
 <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:"
  />
 </LinearLayout>
 </LinearLayout>
<SeekBar
 android:id="@+id/zoombar"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:max="20"
  android:progress="0"/>
<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.view.View;
import android.widget.CheckBox;
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 CheckBox mySatellite;

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();
};

private void SetSatellite()
{
 myMapView.setSatellite(mySatellite.isChecked());
};

/** 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);
 mySatellite = (CheckBox)findViewById(R.id.satellite);

 SetSatellite();
 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);
 mySatellite.setOnClickListener(mySatelliteOnClickListener);
}

private CheckBox.OnClickListener mySatelliteOnClickListener =
 new CheckBox.OnClickListener(){

  public void onClick(View v) {
   // TODO Auto-generated method stub
   SetSatellite();
  }

};

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.

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.

MapView to center on the current location from GPS

In the article Read GPS location, LocationManager described how to get current location from GPS.
In the article A minimal Map application using MapActivity, described how to implemented a MapView with MapActiity.

In this article, both exercises are merged to have a MapView, which will center in the current location from GPS.



Please note that the application cannot be run directly, you have to have your own API Key to using the GPS API. Refer to the article A minimal Map application using MapActivity to obtain API Key.

Modify AndroidManifest.xml:
Add <uses-library android:name="com.google.android.maps" /> as a child of the <application> element.
Add <uses-permission android:name="android.permission.INTERNET" />
and <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> as children of the <manifest> element.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.AndroidLocation"
     android:versionCode="1"
     android:versionName="1.0">
   <application android:icon="@drawable/icon" android:label="@string/app_name">
       <activity android:name=".AndroidLocation"
                 android:label="@string/app_name">
           <intent-filter>
               <action android:name="android.intent.action.MAIN" />
               <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>
  <uses-library android:name="com.google.android.maps" />
   </application>
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
   <uses-sdk android:minSdkVersion="5" />
</manifest>

Modify main.xml to have a MapView

<?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="fill_parent"
     android:text="Longitude:"
  />
  <TextView
   android:id="@+id/latitude"
   android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:text="Latitude:"
  />
 </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>

Finally, modify 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.TextView;

public class AndroidLocation extends MapActivity {

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

 private void CenterLocatio(GeoPoint centerGeoPoint)
 {
  myMapController.animateTo(centerGeoPoint);
  
 
  myLongitude.setText("Longitude: "+
   String.valueOf((float)centerGeoPoint.getLongitudeE6()/1000000)
   );
  myLatitude.setText("Latitude: "+
   String.valueOf((float)centerGeoPoint.getLatitudeE6()/1000000)
   );
 };

 /** 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);
  myMapView.setSatellite(true); //Set satellite view
  myMapController = myMapView.getController();
  myMapController.setZoom(20); //Fixed Zoom Level

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

  myLocationListener = new MyLocationListener();

  myLocationManager.requestLocationUpdates(
    LocationManager.GPS_PROVIDER,
    0,
    0,
    myLocationListener);
  
  //Get the current location in start-up
  GeoPoint initGeoPoint = new GeoPoint(
   (int)(myLocationManager.getLastKnownLocation(
    LocationManager.GPS_PROVIDER)
    .getLatitude()*1000000),
   (int)(myLocationManager.getLastKnownLocation(
    LocationManager.GPS_PROVIDER)
    .getLongitude()*1000000));
   CenterLocatio(initGeoPoint);
 }

 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));
   
   CenterLocatio(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.

Also refer Enable "Use wireless networks" and "Use GPS satellites" in Android Emulator and Change GPS location of Android Emulator.

Because te application read location in start-up, 
so you have to send GPS Location to Android Emulator 
at least once before the application start.

Edited@11-11-2009