Android Open Source - android-roadkill Map Choose

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License

The source code is released under:
GNU General Public License
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Java Source Code

/*This Map View allows the user to choose coordinates by dragging a pin to the desired location*/
/* w w w. j  av a  2s.  c  om*/
package edu.ucdavis.cros.roadkill;

import java.util.ArrayList;
import java.util.List;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.graphics.Point;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.Toast;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;

public class MapChoose extends MapActivity {

  public static final String EXTRA_LATITUDE = "edu.ucdavis.cros.roadkill.EXTRA_LATITUDE";
  public static final String EXTRA_LONGITUDE = "edu.ucdavis.cros.roadkill.EXTRA_LONGITUDE";
  public static final String EXTRA_NAME = "edu.ucdavis.cros.roadkill.EXTRA_NAME";

  private LinearLayout linearLayout;
  private MapView mapView;
  private List<Overlay> mapOverlays;
  private Drawable drawable;
  private Overlays overlays;
  private static String LAT;
  private static String LON;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mapchoose);

    double latitude = Double.parseDouble(getIntent().getStringExtra(
        EXTRA_LATITUDE));
    double longitude = Double.parseDouble(getIntent().getStringExtra(
        EXTRA_LONGITUDE));

    Toast.makeText(MapChoose.this, "Drag pin to desired location.",
        Toast.LENGTH_SHORT).show();

    // set the starting center of map
    GeoPoint start = getPoint(latitude, longitude);

    // sets up mapview
    mapView = (MapView) findViewById(R.id.mapview);
    mapView.setBuiltInZoomControls(true); // sets up zoom control
    mapView.getController().setZoom(10); // sets default zoom
    mapView.getController().setCenter(start); // sets default map location

    // sets up overlay items
    mapOverlays = mapView.getOverlays();
    drawable = this.getResources().getDrawable(R.drawable.pin);
    overlays = new Overlays(drawable);

    // creates a pin at our starting center
    GeoPoint point = getPoint(latitude, longitude);
    OverlayItem pin = new OverlayItem(point, "California", "Davis");

    // adds the pin to our list
    overlays.addOverlay(pin);
    mapOverlays.add(overlays);
  }

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

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

  public void onClick(View v) {
    switch (v.getId()) {
    case R.id.select:
      overlays.promptCoordinates();
      break;
    }
  }

  // this class deals with overlay items
  public class Overlays extends ItemizedOverlay<OverlayItem> {

    // list of overlay items we wish to add to map
    private ArrayList<OverlayItem> myOverlays = new ArrayList<OverlayItem>();

    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;

    public Overlays(Drawable defaultMarker) {
      super(boundCenterBottom(defaultMarker));
      this.marker = defaultMarker;

      dragImage = (ImageView) findViewById(R.id.drag);
      xDragImageOffset = dragImage.getDrawable().getIntrinsicWidth() / 2;
      yDragImageOffset = dragImage.getDrawable().getIntrinsicHeight();
    }

    // adds the overlay items
    public void addOverlay(OverlayItem overlay) {
      myOverlays.add(overlay);
      populate();
    }

    // populate() calls this method to read from our overlay list
    @Override
    protected OverlayItem createItem(int i) {
      return myOverlays.get(i);
    }

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

    // method that controls the movable overlay item
    @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 : myOverlays) {
          Point p = new Point(0, 0);

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

          if (hitTest(item, marker, x - p.x, y - p.y)) {
            result = true;
            inDrag = item;
            myOverlays.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 = mapView.getProjection().fromPixels(
            x - xDragTouchOffset, y - yDragTouchOffset);
        OverlayItem toDrop = new OverlayItem(pt, inDrag.getTitle(),
            inDrag.getSnippet());

        myOverlays.add(toDrop);
        populate();

        // show toast of coordinates
        GeoPoint p = mapview.getProjection().fromPixels(
            (int) event.getX(), (int) event.getY());
        LAT = Double.toString(p.getLatitudeE6() / 1E6);
        LON = Double.toString(p.getLongitudeE6() / 1E6);
        Toast.makeText(MapChoose.this, LAT + ", " + LON,
            Toast.LENGTH_SHORT).show();

        inDrag = null;
        result = true;
      }

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

    // sets image position
    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);
    }

    // show alert that prompts user to confirm coordinates
    private void promptCoordinates() {
      AlertDialog.Builder alert = new AlertDialog.Builder(MapChoose.this);
      alert.setTitle("Choose this coordinate?");
      alert.setMessage(LAT + ", " + LON);

      // is user chooses yes, return to main activity
      alert.setPositiveButton("Yes",
          new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,
                int whichButton) {
              Roadkill.LATITUDE = LAT;
              Roadkill.LONGITUDE = LON;
              setResult(MapChoose.RESULT_OK);
              finish();
            }
          });
      // if user chooses no, let them choose again
      alert.setNegativeButton("No",
          new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,
                int whichButton) {
              Toast.makeText(MapChoose.this,
                  "Drag pin to desired location.",
                  Toast.LENGTH_SHORT).show();
            }
          });
      alert.show();
    }

  }

}
Java Source Code List
