Android使用百度地图API实现GPS步行轨迹

百度地图Android SDK下载：http://developer.baidu.com/map/sdkandev-download.htm

下面是效果：





采样点取得太频繁所以看起来像是一个个点。。。 可以自己设计算法只取有用的点。

为了方便，我直接修改百度提供的示例代码。





要修改的是BMapApiDemoApp.java,LocationOverlay.java还有自定义一个继承自Overlay的RunLineOverlay。

BMapApiDemoApp:

public class BMapApiDemoApp extends Application {

static BMapApiDemoApp mDemoApp;

//百度MapAPI的管理类
BMapManager mBMapMan = null;

// 授权Key
// TODO: 请输入您的Key,
// 申请地址：http://dev.baidu.com/wiki/static/imap/key/
String mStrKey = "你的Key";
boolean m_bKeyRight = true;    // 授权Key正确，验证通过

// 常用事件监听，用来处理通常的网络错误，授权验证错误等
static class MyGeneralListener implements MKGeneralListener {
@Override
public void onGetNetworkState(int iError) {
Log.d("MyGeneralListener", "onGetNetworkState error is "+ iError);
Toast.makeText(BMapApiDemoApp.mDemoApp.getApplicationContext(), "您的网络出错啦！",
Toast.LENGTH_LONG).show();
}

@Override
public void onGetPermissionState(int iError) {
Log.d("MyGeneralListener", "onGetPermissionState error is "+ iError);
if (iError ==  MKEvent.ERROR_PERMISSION_DENIED) {
// 授权Key错误：
Toast.makeText(BMapApiDemoApp.mDemoApp.getApplicationContext(),
"请在BMapApiDemoApp.java文件输入正确的授权Key！",
Toast.LENGTH_LONG).show();
BMapApiDemoApp.mDemoApp.m_bKeyRight = false;
}
}
}

@Override
public void onCreate() {
Log.v("BMapApiDemoApp", "onCreate");
mDemoApp = this;
mBMapMan = new BMapManager(this);
boolean isSuccess = mBMapMan.init(this.mStrKey, new MyGeneralListener());
// 初始化地图sdk成功，设置定位监听时间
if (isSuccess) {
mBMapMan.getLocationManager().enableProvider(MKLocationManager.MK_GPS_PROVIDER);
mBMapMan.getLocationManager().setNotifyInternal(10, 5);
}
else {
// 地图sdk初始化失败，不能使用sdk
}

super.onCreate();
}

@Override
//建议在您app的退出之前调用mapadpi的destroy()函数，避免重复初始化带来的时间消耗
public void onTerminate() {
// TODO Auto-generated method stub
if (mBMapMan != null) {
mBMapMan.destroy();
mBMapMan = null;
}
super.onTerminate();
}

}

mStrKey的值是你申请来的Key，申请地址上面有。

onCreate里加了句mBMapMan.getLocationManager().enableProvider(MKLocationManager.MK_GPS_PROVIDER);用来打开GPS位置。

RunLineOverlay：

public class RunLineOverlay extends Overlay {

private List<GeoPoint> mList;

public RunLineOverlay() {
// TODO Auto-generated constructor stub
super();
mList=new ArrayList<GeoPoint>();
}

@Override
public void draw(Canvas arg0, MapView arg1, boolean arg2) {
// TODO Auto-generated method stub
super.draw(arg0, arg1, arg2);
Projection projection = arg1.getProjection();
Paint paint=new Paint();
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5.0f);

Point p1=projection.toPixels(mList.get(0), null);
Point p2=projection.toPixels(mList.get(0), null);
for (GeoPoint item : mList) {
p1.x=p2.x;
p1.y=p2.y;
p2=projection.toPixels(item, null);
arg0.drawLine(p1.x, p1.y, p2.x, p2.y, paint);
}

}

public List<GeoPoint> getmList() {
return mList;
}

public void setmList(List<GeoPoint> mList) {
this.mList = mList;
}

public void addGeoPoint(GeoPoint point){

mList.add(point);
}

}

这是一个自定义的用于在底图上根据点画出轨迹的覆盖物。Projection用于经纬度和屏幕像素点的转换。大概功能就是取出经纬度点然后转成屏幕像素点然后连成轨迹。

LocationOverlay：

public class LocationOverlay extends MapActivity {

MapView mMapView = null;
LocationListener mLocationListener = null;//onResume时注册此listener，onPause时需要Remove
MyLocationOverlay mLocationOverlay = null;    //定位图层
RunLineOverlay mRunLine=null;

protected void onCreate(Bundle savedInstanceState) {

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

BMapApiDemoApp app = (BMapApiDemoApp)this.getApplication();
if (app.mBMapMan == null) {
app.mBMapMan = new BMapManager(getApplication());
app.mBMapMan.init(app.mStrKey, new BMapApiDemoApp.MyGeneralListener());
}
app.mBMapMan.start();
// 如果使用地图SDK，请初始化地图Activity
super.initMapActivity(app.mBMapMan);

mMapView = (MapView)findViewById(R.id.bmapView);
mMapView.setBuiltInZoomControls(true);
//设置在缩放动画过程中也显示overlay,默认为不绘制
mMapView.setDrawOverlayWhenZooming(true);

// 添加定位图层
mLocationOverlay = new MyLocationOverlay(this, mMapView);
mMapView.getOverlays().add(mLocationOverlay);

// 注册定位事件
mLocationListener = new LocationListener(){

@Override
public void onLocationChanged(Location location) {
if (location != null){
GeoPoint pt = new GeoPoint((int)(location.getLatitude()*1e6),
(int)(location.getLongitude()*1e6));
if(mRunLine==null)
{mRunLine=new RunLineOverlay();
mRunLine.addGeoPoint(pt);
mMapView.getOverlays().add(mRunLine);}else
mRunLine.addGeoPoint(pt);
mMapView.getController().animateTo(pt);
}
}
};
}

@Override
protected void onPause() {
BMapApiDemoApp app = (BMapApiDemoApp)this.getApplication();
app.mBMapMan.getLocationManager().removeUpdates(mLocationListener);
mLocationOverlay.disableMyLocation();
mLocationOverlay.disableCompass(); // 关闭指南针
app.mBMapMan.stop();
super.onPause();
}
@Override
protected void onResume() {
BMapApiDemoApp app = (BMapApiDemoApp)this.getApplication();
// 注册定位事件，定位后将地图移动到定位点
app.mBMapMan.getLocationManager().requestLocationUpdates(mLocationListener);
mLocationOverlay.enableMyLocation();
mLocationOverlay.enableCompass(); // 打开指南针
app.mBMapMan.start();
super.onResume();
}

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

}

主要修改的代码是

public void onLocationChanged(Location location) {
if (location != null){
GeoPoint pt = new GeoPoint((int)(location.getLatitude()*1e6),
(int)(location.getLongitude()*1e6));
if(mRunLine==null)
{mRunLine=new RunLineOverlay();
mRunLine.addGeoPoint(pt);
mMapView.getOverlays().add(mRunLine);}else
mRunLine.addGeoPoint(pt);
mMapView.getController().animateTo(pt);
}

当位置改变是这个方法会被调用。功能就是把新位置放入mRunLine。当然第一次要mMapView.getOverlays().add(mRunLine);把mRunLine放进mMapView的覆盖物列表，这样当mMapView被重绘时mRunLine的draw方法就会被调用。

改好后运行程序，列表点击Overlaytest，然后出去转一圈。