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Android Google Map如何检查gps位置是否在圈内

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恢弘志士之气，不宜妄自菲薄。这篇文章主要讲述Android Google Map如何检查gps位置是否在圈内相关的知识，希望能为你提供帮助。
我正在尝试使用用户gps位置检测用户是否在标记的半径内。我有标记的坐标，但我不知道如何计算用户是否在该区域。我试过使用以下内容，但即使当前位置在圈内，我仍然会收到“外部”消息。

public class MapaEscola extends FragmentActivity {private GoogleMap googleMap; private Serializable escolas; private ProgressDialog dialog; private Circle mCircle; private Marker mMarker; @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH) @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getActionBar().setDisplayHomeAsUpEnabled(true); getActionBar().setHomeButtonEnabled(true); setContentView(R.layout.maps); // Loading map initilizeMap(); // Changing map type googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); // Showing / hiding your current location googleMap.setMyLocationEnabled(true); // Enable / Disable zooming controls googleMap.getUiSettings().setZoomControlsEnabled(true); // Enable / Disable my location button googleMap.getUiSettings().setMyLocationButtonEnabled(true); // Enable / Disable Compass icon googleMap.getUiSettings().setCompassEnabled(true); // Enable / Disable Rotate gesture googleMap.getUiSettings().setRotateGesturesEnabled(true); // Enable / Disable zooming functionality googleMap.getUiSettings().setZoomGesturesEnabled(true); Bundle extra = getIntent().getBundleExtra("extra"); ArrayList< Escolas> objects = (ArrayList< Escolas> ) extra.getSerializable("array"); try {for(int i = 0; i < objects.size(); i ++) { System.out.println(" escolas " + objects.get(i).getLatitude() + " " + objects.get(i).getLongitude()); float latitude = objects.get(i).getLatitude(); float longitude = objects.get(i).getLongitude(); googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(-23.316281, -51.155528), 15)); MarkerOptions options = new MarkerOptions(); // Setting the position of the markeroptions.position(new LatLng(latitude, longitude)); googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap(); LatLng latLng = new LatLng(latitude, longitude); drawMarkerWithCircle(latLng); googleMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() { @Override public void onMyLocationChange(Location location) { float[] distance = new float[2]; Location.distanceBetween( mMarker.getPosition().latitude, mMarker.getPosition().longitude, mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance); if( distance[0] > (mCircle.getRadius() / 2)){ Toast.makeText(getBaseContext(), "Outside", Toast.LENGTH_LONG).show(); } else { Toast.makeText(getBaseContext(), "Inside", Toast.LENGTH_LONG).show(); }} }); }} catch (Exception e) { e.printStackTrace(); } }private void drawMarkerWithCircle(LatLng position){ double radiusInMeters = 500.0; int strokeColor = 0xffff0000; //red outline int shadeColor = 0x44ff0000; //opaque red fillCircleOptions circleOptions = new CircleOptions().center(position).radius(radiusInMeters).fillColor(shadeColor).strokeColor(strokeColor).strokeWidth(8); mCircle = googleMap.addCircle(circleOptions); MarkerOptions markerOptions = new MarkerOptions().position(position); mMarker = googleMap.addMarker(markerOptions); }private void initilizeMap() {if (googleMap == null) { googleMap = ((MapFragment) getFragmentManager().findFragmentById( R.id.map)).getMap(); // check if map is created successfully or not if (googleMap == null) { Toast.makeText(getApplicationContext(), "N?o foi possível carregar o mapa", Toast.LENGTH_SHORT) .show(); } } }@TargetApi(Build.VERSION_CODES.HONEYCOMB) @Override public void onBackPressed() {super.onBackPressed(); finish(); }@Override public boolean onCreateOptionsMenu(Menu menu) { // TODO Auto-generated method stub MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.menu_main, menu); return super.onCreateOptionsMenu(menu); }@TargetApi(Build.VERSION_CODES.HONEYCOMB) public boolean onOptionsItemSelected(MenuItem item) {switch (item.getItemId()) {case android.R.id.home: super.onBackPressed(); finish(); return true; }return true; }@Override protected void onResume() { super.onResume(); initilizeMap(); }}

答案我刚刚运行了更新的代码并找出了主要问题。
您应该使用传递给Location回调的onMyLocationChange()，以便它使用您当前的位置来判断设备是否在圈内：
googleMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() { @Override public void onMyLocationChange(Location location) { float[] distance = new float[2]; /* Location.distanceBetween( mMarker.getPosition().latitude, mMarker.getPosition().longitude, mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance); */Location.distanceBetween( location.getLatitude(), location.getLongitude(), mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance); if( distance[0] > mCircle.getRadius() ){ Toast.makeText(getBaseContext(), "Outside, distance from center: " + distance[0] + " radius: " + mCircle.getRadius(), Toast.LENGTH_LONG).show(); } else { Toast.makeText(getBaseContext(), "Inside, distance from center: " + distance[0] + " radius: " + mCircle.getRadius() , Toast.LENGTH_LONG).show(); }} });

这是我运行的完整工作示例，它是原始代码的简化版本：
public class MainActivity extends ActionBarActivity {private GoogleMap googleMap; private Serializable escolas; private ProgressDialog dialog; private Circle mCircle; private Marker mMarker; @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH) @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getSupportActionBar().setDisplayHomeAsUpEnabled(true); getSupportActionBar().setHomeButtonEnabled(true); setContentView(R.layout.activity_main); // Loading map initilizeMap(); // Changing map type googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL); // Showing / hiding your current location googleMap.setMyLocationEnabled(true); // Enable / Disable zooming controls googleMap.getUiSettings().setZoomControlsEnabled(true); // Enable / Disable my location button googleMap.getUiSettings().setMyLocationButtonEnabled(true); // Enable / Disable Compass icon googleMap.getUiSettings().setCompassEnabled(true); // Enable / Disable Rotate gesture googleMap.getUiSettings().setRotateGesturesEnabled(true); // Enable / Disable zooming functionality googleMap.getUiSettings().setZoomGesturesEnabled(true); // Bundle extra = getIntent().getBundleExtra("extra"); //ArrayList< Escolas> objects = (ArrayList< Escolas> ) extra.getSerializable("array"); try { //test outside double mLatitude = 37.77657; double mLongitude = -122.417506; //test inside //double mLatitude = 37.7795516; //double mLongitude = -122.39292; googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(mLatitude, mLongitude), 15)); MarkerOptions options = new MarkerOptions(); // Setting the position of the markeroptions.position(new LatLng(mLatitude, mLongitude)); //googleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); LatLng latLng = new LatLng(mLatitude, mLongitude); drawMarkerWithCircle(latLng); googleMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() { @Override public void onMyLocationChange(Location location) { float[] distance = new float[2]; /* Location.distanceBetween( mMarker.getPosition().latitude, mMarker.getPosition().longitude, mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance); */Location.distanceBetween( location.getLatitude(), location.getLongitude(), mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance); if( distance[0] > mCircle.getRadius()){ Toast.makeText(getBaseContext(), "Outside, distance from center: " + distance[0] + " radius: " + mCircle.getRadius(), Toast.LENGTH_LONG).show(); } else { Toast.makeText(getBaseContext(), "Inside, distance from center: " + distance[0] + " radius: " + mCircle.getRadius() , Toast.LENGTH_LONG).show(); }} }); } catch (Exception e) { e.printStackTrace(); } }private void drawMarkerWithCircle(LatLng position){ double radiusInMeters = 500.0; int strokeColor = 0xffff0000; //red outline int shadeColor = 0x44ff0000; //opaque red fillCircleOptions circleOptions = new CircleOptions().center(position).radius(radiusInMeters).fillColor(shadeColor).strokeColor(strokeColor).strokeWidth(8); mCircle = googleMap.addCircle(circleOptions); MarkerOptions markerOptions = new MarkerOptions().position(position); mMarker = googleMap.addMarker(markerOptions); }private void initilizeMap() {if (googleMap == null) { googleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById( R.id.map)).getMap(); // check if map is created successfully or not if (googleMap == null) { Toast.makeText(getApplicationContext(), "N?o foi possível carregar o mapa", Toast.LENGTH_SHORT) .show(); } } }@TargetApi(Build.VERSION_CODES.HONEYCOMB) @Override public void onBackPressed() {super.onBackPressed(); finish(); }@Override public boolean onCreateOptionsMenu(Menu menu) { // TODO Auto-generated method stub MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.menu_main, menu); return super.onCreateOptionsMenu(menu); }@TargetApi(Build.VERSION_CODES.HONEYCOMB) public boolean onOptionsItemSelected(MenuItem item) {switch (item.getItemId()) {case android.R.id.home: super.onBackPressed(); finish(); return true; }return true; }@Override protected void onResume() { super.onResume(); initilizeMap(); }}

圈内的结果：

圈外的结果：

另一答案@Daniel Nugent：imho getRadius()将返回半径而不是直径所以“/2”是错误的
@WARpoluido：我看不到位置变化时更新mMarker变量。你为什么不使用给onMyLocationChange()的价值？
Location.distanceBetween( mCircle.getCenter().latitude, mCircle.getCenter().longitude, location.getLatitude(), location.getLongitude(), distance); if( distance[0] > mCircle.getRadius() ){ ...

另一答案【Android Google Map如何检查gps位置是否在圈内】嗨，我已经使用此代码正常工作了
//Getting current location private void getCurrentLocation() { mMap.clear(); //Creating a location object Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient); if (location != null) { //Getting longitude and latitude longitude = location.getLongitude(); latitude = location.getLatitude(); //moving the map to location moveMap(); }Circle circle = mMap.add

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