Android Google Map的基本使用

一、GoogleMap的介绍

谷歌地图是 Google 公司提供的电子地图服务，包括局部详细的卫星照片。此款服务可以提供含有政区和交通以及商业信息的矢量地图、不同分辨率的卫星照片和可以用来显示地形和等高线地形视图。在各类平台均有应用，操作简单方便。

二、获取Maps API Key

应用程序签名：

1.Android系统要求所有应用程序都必须使用证书进行签名：

2.在证书当中包含一个唯一的key；

3.证书用于标示应用程序的作者；

4.在开发和调试的过程的当中可以使用debug key（C:\Users\<user>\.android\）；

生成证书指纹：

创建过程详细请参见Google Maps Android API

https://developers.google.com/maps/documentation/android/start?hl=zh-CN

三、在地图当中使用标记的步骤

1.在MapView之上创建一个单独的图层；

2.创建标记对象；

3.将标记显示在指定图层的指定位置；

4.处理点击标记事件；

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ItemizedOverlay
//在MapView上创建一个图层，需要创建一个类，实现overlay，并生成该类的对象，然后将该对象添加到MapView.getOverlays()
public class CustomItemizedOverlay extends ItemizedOverlay<OverlayItem> {

private ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>();

private Context context;

public CustomItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
}

public CustomItemizedOverlay(Drawable defaultMarker, Context context) {
this(defaultMarker);
this.context = context;
}

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

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

@Override
protected boolean onTap(int index) {
OverlayItem item = mapOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(context);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}

public void addOverlay(OverlayItem overlay) {
mapOverlays.add(overlay);
this.populate();
}

}

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/**
* 显示地图，并且有图层，做标记等
*
*/
public class MainActivity extends MapActivity {

private MapView mapView;
// 19240000，-99120000
private static final int latitudeE6 = 37985339;
private static final int longitudeE6 = 23716735;

@Override
public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.main2);

mapView = (MapView) findViewById(R.id.map_view);
// 设置显示用于缩放的工具条
mapView.setBuiltInZoomControls(true);

// 得到所有的图层对象
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.icon);
// 生成自定义图层类得对象
CustomItemizedOverlay itemizedOverlay =
new CustomItemizedOverlay(drawable, this);

// 创建一个GeoPoint对象，通过经纬度，指定地图上的一个点
GeoPoint point = new GeoPoint(latitudeE6, longitudeE6);
OverlayItem overlayitem =
new OverlayItem(point, "Hello", "I'm in Athens, Greece!");

itemizedOverlay.addOverlay(overlayitem);

mapOverlays.add(itemizedOverlay);

MapController mapController = mapView.getController();
mapController.animateTo(point);
mapController.setZoom(12);
}

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

四、在地图上绘制线条的方法

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/**
* 在地图上绘制路线
*
* Projection 的作用：
* 1.将地图上的经纬度坐标转化成屏幕上的X轴和Y轴上的坐标点
* android.graphics.Point toPixcels(GeoPoint in, android.graphics.Point out);
* 2.将X轴和Y轴的坐标转化成地图上的经纬度坐标
* GeoPoint fromPixels(int x, int y);
*/
public class MainActivity extends MapActivity {
Projection projection;
private MapController mapController;
private List<Overlay> overLays;
private GeoPoint beginGeoPoint;
private GeoPoint endGeoPoint;
private MapView mapView;

@Override
public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.main2);

// 指定起始和终止位置的经纬度
beginGeoPoint = new GeoPoint(19240000, -99120000);
endGeoPoint = new GeoPoint(19340000, -99220000);

mapView = (MapView) findViewById(R.id.map_view);
// 设置显示用于缩放的工具条
mapView.setBuiltInZoomControls(true);

// 得到所有的工具类
overLays = mapView.getOverlays();
mapController = mapView.getController();
projection = mapView.getProjection();

overLays.add(new PointOverlay(beginGeoPoint));
overLays.add(new PointOverlay(endGeoPoint));
overLays.add(new LineOverLay(beginGeoPoint, endGeoPoint));

mapController.animateTo(beginGeoPoint);
mapController.setZoom(12);

}

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

/**
* 该类得对象用于在地图上绘制线条
*
*/
class LineOverLay extends Overlay {
GeoPoint begin;
GeoPoint end;

public LineOverLay() {

}

public LineOverLay(GeoPoint begin, GeoPoint end) {
super();
this.begin = begin;
this.end = end;
}

public void draw(Canvas canvas, MapView mapView, boolean shadow) {
super.draw(canvas, mapView, shadow);
// 设置画笔属性
Paint paint = new Paint();
paint.setColor(Color.BLUE);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setStrokeWidth(2);

Point beginPoint = new Point();
Point endPoint = new Point();

Path path = new Path();
// 把经纬度坐标转换成点的坐标
projection.toPixels(beginGeoPoint, beginPoint);
projection.toPixels(endGeoPoint, endPoint);

path.moveTo(endPoint.x, endPoint.y);
path.lineTo(beginPoint.x, beginPoint.y);
canvas.drawPath(path, paint);
}
}

/**
* 该类得对象作用是在地图上绘制图标
*
*/
class PointOverlay extends Overlay{
private GeoPoint geoPoint;
public PointOverlay( ) {

}

public PointOverlay(GeoPoint geoPoint) {
super();
this.geoPoint = geoPoint;
}

public void draw(Canvas canvas, MapView mapView, boolean shadow) {
super.draw(canvas, mapView, shadow);
Point point = new Point();
projection.toPixels(geoPoint, point);
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.tools);

Paint paint = new Paint();
canvas.drawBitmap(bmp, point.x, point.y, paint);
// 这里如果想要图标指向图片的左下角，用point.y减去图片的高度即可
}

}
}