首先，我是 android 和 JAVA 的新手，并且是 stackoverflow 的注册用户，但它多次帮助我找到了一个好的答案，所以，感谢这个社区，让我在学校项目中多次摆脱困境我在这里因为我被困在这个小项目中，是一所大学，所以不涉及任何资金。
我正在尝试显示路线并在使用 android google maps api 在城市中移动时对其进行更新。到目前为止，我设法获得了我的位置，并且可以显示两点之间的路线，但是问题是当我想从当前位置获得起点时，似乎无法将其保存到变量中（或者我不知道怎么做）我使用谷歌示例作为地图显示的基础。我将发布整个代码，也许有人也会发现它有用。因为是一个大学的小项目，我没有秘密要隐藏，我在这里学习，所以很高兴发布完整的代码。如果有人对我的问题有提示，我将不胜感激。谢谢！注意：问题是让这个婴儿显示从我当前位置到第二个固定位置的路线。主要代码如下：
public class mapDisplay extends ActionBarMapActivity {
private LocationManager myLocationManager;
private LocationListener myLocationListener;
private MapController myMapController;
private MapView myMapView;
private MyLocationOverlay myLocation;
private void CenterLocatio(GeoPoint centerGeoPoint)
{
myMapController.animateTo(centerGeoPoint);
};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map_screen);
myMapView = (MapView) findViewById(R.id.mapview);
//mapView.setBuiltInZoomControls(true);
myMapView.setSatellite(false); //Set satellite view
myMapController = myMapView.getController();
myMapController.setZoom(15); //Fixed Zoom Level
myLocationManager = (LocationManager)getSystemService(
Context.LOCATION_SERVICE);
//For enable location services dialogue
if (!myLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
createGpsDisabledAlert();
}
// see createGpsDisabledAlert function below
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);
//draw the sample route
MapView mv = (MapView) findViewById(R.id.mapview);
mv.setBuiltInZoomControls(true);
MapController mc = mv.getController();
ArrayList all_geo_points = getDirections(50.0536, 8.69339, 50.021973, 8.69584);
GeoPoint moveTo = (GeoPoint) all_geo_points.get(0);
mc.animateTo(moveTo);
mc.setZoom(12);
mv.getOverlays().add(new MyOverlay(all_geo_points));
//Adding position icon for current location
// Add the MyLocationOverlay
myLocation = new MyLocationOverlay(this, myMapView);
myMapView.getOverlays().add(myLocation);
myLocation.enableMyLocation();
myLocation.runOnFirstFix(new Runnable() {
public void run() {
myMapController.animateTo(myLocation.getMyLocation());
}
});
}
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
//toast shown if GPS is disabled
Context context = getApplicationContext();
CharSequence text = "GPS is disabled! If you want to take full advantage of map please enable the GPS!";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
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 void onResume() {
super.onResume();
myLocation.enableMyLocation();
}
@Override
protected void onPause() {
super.onPause();
myLocation.disableMyLocation();
}
//Back button press returns to first activity (selection screen)
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
//super.onBackPressed();
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
//rest of functions for GPS alert
private void createGpsDisabledAlert(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Your GPS is disabled! Would you like to enable it?")
.setCancelable(false)
.setPositiveButton("Enable GPS",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
showGpsOptions();
}
});
builder.setNegativeButton("Do nothing",
new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int id){
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
private void showGpsOptions(){
Intent gpsOptionsIntent = new Intent(
android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(gpsOptionsIntent);
}
//Testing - directions
public static ArrayList getDirections(double lat1, double lon1, double lat2, double lon2) {
String url = "http://maps.googleapis.com/maps/api/directions/xml?origin=" +lat1 + "," + lon1 + "&destination=" + lat2 + "," + lon2 + "&sensor=false&units=metric";
String tag[] = { "lat", "lng" };
ArrayList list_of_geopoints = new ArrayList();
HttpResponse response = null;
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url);
response = httpClient.execute(httpPost, localContext);
InputStream in = response.getEntity().getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = builder.parse(in);
if (doc != null) {
NodeList nl1, nl2;
nl1 = doc.getElementsByTagName(tag[0]);
nl2 = doc.getElementsByTagName(tag[1]);
if (nl1.getLength() > 0) {
list_of_geopoints = new ArrayList();
for (int i = 0; i < nl1.getLength(); i++) {
Node node1 = nl1.item(i);
Node node2 = nl2.item(i);
double lat = Double.parseDouble(node1.getTextContent());
double lng = Double.parseDouble(node2.getTextContent());
list_of_geopoints.add(new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6)));
}
} else {
// No points found
}
}
} catch (Exception e) {
e.printStackTrace();
}
return list_of_geopoints;
}}
编辑10.07.2012：我开始怀疑这是一个愚蠢的问题，没有人知道答案或没有人想回答。我试图保存到局部变量中并在 get Directions() 函数中使用它们，但由于某种原因导致我的应用程序崩溃。或者更好的是，我被邀请在编译之前修复错误。