我正在创建一个用户可以在其中跟踪从他运行到哪里的路径的地方。我尝试了以下代码，它可以正常工作，但是在运行它时，开始滞后，任何人都可以告诉我我在哪里做错了。
要绘制折线，我会在一段时间后刷新地图
public class MapsActivity extends AppCompatActivity implements OnMapReadyCallback {
private static final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 5445;
private GoogleMap googleMap;
private FusedLocationProviderClient fusedLocationProviderClient;
private Marker currentLocationMarker;
private Location currentLocation;
private boolean firstTimeFlag = true;
private ArrayList<LatLng> points =new ArrayList<>(); //added
Polyline line; //added
/* private final View.OnClickListener clickListener = view -> {
if (view.getId() == R.id.currentLocationImageButton && googleMap != null && currentLocation != null)
animateCamera(currentLocation);
};
*/
private final LocationCallback mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
if (locationResult.getLastLocation() == null)
return;
currentLocation = locationResult.getLastLocation();
if (firstTimeFlag && googleMap != null) {
animateCamera(currentLocation);
firstTimeFlag = false;
}
showMarker(currentLocation);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
SupportMapFragment supportMapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
supportMapFragment.getMapAsync(this);
// findViewById(R.id.currentLocationImageButton).setOnClickListener(clickListener);
}
@Override
public void onMapReady(GoogleMap googleMap) {
this.googleMap = googleMap;
}
private void startCurrentLocationUpdates() {
LocationRequest locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(3000);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MapsActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
return;
}
}
fusedLocationProviderClient.requestLocationUpdates(locationRequest, mLocationCallback, Looper.myLooper());
}
private boolean isGooglePlayServicesAvailable() {
GoogleApiAvailability googleApiAvailability = GoogleApiAvailability.getInstance();
int status = googleApiAvailability.isGooglePlayServicesAvailable(this);
if (ConnectionResult.SUCCESS == status)
return true;
else {
if (googleApiAvailability.isUserResolvableError(status))
Toast.makeText(this, "Please Install google play services to use this application", Toast.LENGTH_LONG).show();
}
return false;
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION) {
if (grantResults[0] == PackageManager.PERMISSION_DENIED)
Toast.makeText(this, "Permission denied by uses", Toast.LENGTH_SHORT).show();
else if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
startCurrentLocationUpdates();
}
}
private void animateCamera(@NonNull Location location) {
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(getCameraPositionWithBearing(latLng)));
}
@NonNull
private CameraPosition getCameraPositionWithBearing(LatLng latLng) {
return new CameraPosition.Builder().target(latLng).zoom(16).build();
}
private void showMarker(@NonNull Location currentLocation) {
LatLng latLng = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
if (currentLocationMarker != null){
System.out.println("LastMArkerPostion" + currentLocationMarker.getPosition());
points.add(currentLocationMarker.getPosition());
currentLocationMarker.remove();
}
PolylineOptions options = new PolylineOptions();
for (int i = 0 ; i<points.size() ; i++ ){
options.add(points.get(i)).width(15).color(Color.BLUE).geodesic(true);
googleMap.addPolyline(options);
}
Drawable vectorDrawable = ResourcesCompat.getDrawable(getResources(), R.drawable.ic_green_car_marker, null);
Bitmap bit = Bitmap.createBitmap(vectorDrawable.getIntrinsicWidth(),
vectorDrawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bit);
vectorDrawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
vectorDrawable.draw(canvas);
currentLocationMarker = googleMap.addMarker(new MarkerOptions().icon( BitmapDescriptorFactory.fromBitmap(bit)).position(latLng));
}
@Override
protected void onStop() {
super.onStop();
if (fusedLocationProviderClient != null)
fusedLocationProviderClient.removeLocationUpdates(mLocationCallback);
}
@Override
protected void onResume() {
super.onResume();
if (isGooglePlayServicesAvailable()) {
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
startCurrentLocationUpdates();
}
}
@Override
protected void onDestroy() {
super.onDestroy();
fusedLocationProviderClient = null;
googleMap = null;
}
}
预先感谢
答案 0 :(得分：0)
解决方案
经过大量研究，我在GitHub存储库上找到了解决方案
我对原始代码进行了一些更改
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private static final String TAG = "MapsActivity";
public GoogleMap mMap;
private ArrayList<LatLng> points;
Polyline line;
Marker now;
double lat1;
double lon1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
points = new ArrayList<LatLng>();
setContentView(R.layout.activity_maps);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@SuppressLint("MissingPermission")
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (!mMap.isMyLocationEnabled())
mMap.setMyLocationEnabled(true);
LocationManager lm = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
Location myLocation = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (myLocation == null) {
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_COARSE);
String provider = lm.getBestProvider(criteria, true);
myLocation = lm.getLastKnownLocation(provider);
}
if (myLocation != null) {
LatLng userLocation = new LatLng(myLocation.getLatitude(), myLocation.getLongitude());
lat1=myLocation.getLatitude();
lon1=myLocation.getLongitude();
mMap.addMarker(new MarkerOptions()
.position(userLocation)
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE))
.title("Welcome ")
.snippet("Latitude:"+lat1+",Longitude:"+lon1)
);
Log.v(TAG, "Lat1=" + lat1);
Log.v(TAG, "Long1=" + lon1);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 20), 1500, null);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000,0, new LocationListener() {
@Override
public void onLocationChanged(Location myLocation) {
// Getting latitude of the current location
double latitude = myLocation.getLatitude();
// Getting longitude of the current location
double longitude = myLocation.getLongitude();
// Creating a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
//Adding new marker
/* now = mMap.addMarker(new MarkerOptions()
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_GREEN))
.position(latLng).title("New")
.snippet("Latitude:"+lat1+",Longitude:"+lon1)
);*/
// Showing the current location in Google Map
// mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
// mMap.animateCamera(CameraUpdateFactory.zoomTo(20));
//Draw polyline
drawPolygon(latitude, longitude);
// Toast.makeText(MapsActivity.this, String.valueOf(latitude)+String.valueOf(longitude), Toast.LENGTH_SHORT).show();
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status,
Bundle extras) {
// TODO Auto-generated method stub
}
});
}
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mMap.getUiSettings().setZoomControlsEnabled(true);
}
private void drawPolygon( double latitude, double longitude) {
List<LatLng> polygon = new ArrayList<>();
//old lat and long
polygon.add(new LatLng(lat1, lon1));
//new lat and long
polygon.add(new LatLng(latitude,longitude));
mMap.addPolygon(new PolygonOptions()
.addAll(polygon)
.strokeColor(Color.parseColor("#03A9F4"))
.strokeWidth(15)
.fillColor(Color.parseColor("#B3E5FC"))
);
lat1=latitude;
lon1=longitude;
}
}
完整代码可用于 Github