Drag and drop marker on google map

I have markers. I would like to move the marker with a drag and drop-function, and then check the location where we drop that marker.
1.) In this show google map tiles show on screen and zoom at given level.

MainActivity.java


@Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
 
 
  MapView map = (MapView) findViewById(R.id.map);

  map.getController().setCenter(
  getPoint(40.70686417491799, -74.01572942733765));
  map.getController().setZoom(17);
  map.setBuiltInZoomControls(true);
 }

2.) I was doing some precise measurements with markers on my map, and I wanted my marker to be exactly on the spot I touched and lifted my finger so the measurement was exactly precise.

MainActivity.java


ImageView dragImage=(ImageView) findViewById(R.id.drag);
Drawable marker = getResources().getDrawable(R.drawable.marker);

marker.setBounds(0, 0, marker.getIntrinsicWidth(),
    marker.getIntrinsicHeight());

map.getOverlays().add(new SitesOverlay(marker, dragImage, map));

3.) If you touch "near" the marker, the marker does not go to that exact point, but moves along with your finger's movement. I needed the marker to appear just below my finger on the ACTION_DOWN, ACTION_MOVE and ACTION_UP.

SiteOverLay.java


package com.example.draganddropbasic;
import java.util.ArrayList;
import java.util.List;
import android.graphics.Canvas;
import android.graphics.Point;
import android.graphics.drawable.Drawable;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapView;
import com.google.android.maps.OverlayItem;

public class SitesOverlay extends ItemizedOverlay {
 private List items = new ArrayList();
 private Drawable marker = null;
 private OverlayItem inDrag = null;
 private ImageView dragImage = null;
 private int xDragImageOffset = 0;
 private int yDragImageOffset = 0;
 private int xDragTouchOffset = 0;
 private int yDragTouchOffset = 0;
 MapView map;

 public SitesOverlay(Drawable marker, ImageView dragImage, MapView map) {
  super(marker);
  this.marker = marker;
  this.map = map;
  this.dragImage = dragImage;

  xDragImageOffset = dragImage.getDrawable().getIntrinsicWidth() / 2;
  yDragImageOffset = dragImage.getDrawable().getIntrinsicHeight();

  items.add(new OverlayItem(getPoint(40.748963847316034,
    -73.96807193756104), "UN", "United Nations"));
  items.add(new OverlayItem(getPoint(40.76866299974387,
    -73.98268461227417), "Lincoln Center",
    "Home of Jazz at Lincoln Center"));
  items.add(new OverlayItem(getPoint(40.765136435316755,
    -73.97989511489868), "Carnegie Hall",
    "Where you go with practice, practice, practice"));
  items.add(new OverlayItem(getPoint(40.70686417491799,
    -74.01572942733765), "The Downtown Club",
    "Original home of the Heisman Trophy"));

  populate();
 }

 private GeoPoint getPoint(double lat, double lon) {
  return (new GeoPoint((int) (lat * 1000000.0), (int) (lon * 1000000.0)));
 }

 @Override
 protected OverlayItem createItem(int i) {
  return (items.get(i));
 }

 @Override
 public void draw(Canvas canvas, MapView mapView, boolean shadow) {
  super.draw(canvas, mapView, shadow);

  boundCenterBottom(marker);
 }

 @Override
 public int size() {
  return (items.size());
 }

 @Override
 public boolean onTouchEvent(MotionEvent event, MapView mapView) {
  final int action = event.getAction();
  final int x = (int) event.getX();
  final int y = (int) event.getY();
  boolean result = false;

  if (action == MotionEvent.ACTION_DOWN) {
   for (OverlayItem item : items) {
    Point p = new Point(0, 0);

    map.getProjection().toPixels(item.getPoint(), p);

    if (hitTest(item, marker, x - p.x, y - p.y)) {
     result = true;
     inDrag = item;
     items.remove(inDrag);
     populate();

     xDragTouchOffset = 0;
     yDragTouchOffset = 0;

     setDragImagePosition(p.x, p.y);
     dragImage.setVisibility(View.VISIBLE);

     xDragTouchOffset = x - p.x;
     yDragTouchOffset = y - p.y;

     break;
    }
   }
  } else if (action == MotionEvent.ACTION_MOVE && inDrag != null) {
   setDragImagePosition(x, y);
   result = true;
  } else if (action == MotionEvent.ACTION_UP && inDrag != null) {
   dragImage.setVisibility(View.GONE);

   GeoPoint pt = map.getProjection().fromPixels(x - xDragTouchOffset,
     y - yDragTouchOffset);
   OverlayItem toDrop = new OverlayItem(pt, inDrag.getTitle(),
     inDrag.getSnippet());
   Log.i("info",
     "get lat:" + pt.getLatitudeE6() + " lang:"
       + pt.getLongitudeE6());
   items.add(toDrop);
   populate();

   inDrag = null;
   result = true;
  }

  return (result || super.onTouchEvent(event, mapView));
 }

 private void setDragImagePosition(int x, int y) {
  RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams) dragImage
    .getLayoutParams();

  lp.setMargins(x - xDragImageOffset - xDragTouchOffset, y
    - yDragImageOffset - yDragTouchOffset, 0, 0);
  dragImage.setLayoutParams(lp);
 }
}

4.) MainActivity.java


package com.example.draganddropbasic;

import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.ImageView;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.MyLocationOverlay;

public class MainActivity extends MapActivity {
 private MapView map = null;
 private MyLocationOverlay me = null;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
 
 
  map = (MapView) findViewById(R.id.map);

  map.getController().setCenter(
    getPoint(40.70686417491799, -74.01572942733765));
  map.getController().setZoom(17);
  map.setBuiltInZoomControls(true);

  ImageView dragImage = (ImageView) findViewById(R.id.drag);
  Drawable marker = getResources().getDrawable(R.drawable.marker);

  marker.setBounds(0, 0, marker.getIntrinsicWidth(),
    marker.getIntrinsicHeight());

  map.getOverlays().add(new SitesOverlay(marker, dragImage, map));

  me = new MyLocationOverlay(this, map);
  map.getOverlays().add(me);
 }

 @Override
 public void onResume() {
  super.onResume();

  me.enableCompass();
 }

 @Override
 public void onPause() {
  super.onPause();

  me.disableCompass();
 }

 @Override
 protected boolean isRouteDisplayed() {
  return (false);
 }

 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
  if (keyCode == KeyEvent.KEYCODE_S) {
   map.setSatellite(!map.isSatellite());
   return (true);
  } else if (keyCode == KeyEvent.KEYCODE_Z) {
   map.displayZoomControls(true);
   return (true);
  }

  return (super.onKeyDown(keyCode, event));
 }

 private GeoPoint getPoint(double lat, double lon) {
  return (new GeoPoint((int) (lat * 1000000.0), (int) (lon * 1000000.0)));
 }

}

5.) activity_main.xml


< ?xml version="1.0" encoding="utf-8"?>
< RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    < com.google.android.maps.MapView
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:apiKey="0mjl6OufrY-tHs6WFurtL7rsYyEMpdEqBCbyjXg"
        android:clickable="true" />

    < ImageView
        android:id="@+id/drag"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/marker"
        android:visibility="gone" />

   < /RelativeLayout>

INFO-TECH