本文介绍了Android:拖动地图，同时将标记保持在中心的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我目前正在 MapActivity 中获取设备的当前位置 (lat,lng).现在，我想让用户移动地图，同时将标记保持在中心.这意味着无论何时移动地图，都会更新当前位置.(对吗?)
I am currently getting Current Location of device (lat,lng) in MapActivity. Now , I want to let the user move the map, while keeping the marker at the center. This means that whenever the map is moved, current location will be updated. (Right?)
我关注了这个如何在标记下移动地图? 和 如何在 Uber 和 Lyft 之类的地图上附加灵活的标记? 但我的概念不清楚.
I followed this How to move a map under a marker? and How to attach a flexible marker on map something like Uber and Lyft? but couldn't get my concept clear.
Activity_map.xml(这里我添加了ImageView)
Activity_map.xml (Here I have added ImageView)
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.MapFragment"
/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:src="@drawable/gps"
/>
</RelativeLayout>
我的 MapActivity 如下:
My MapActivity is as follows :
public class MapActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener,GoogleMap.OnInfoWindowClickListener{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
// int x =_st.jsonArray.length();
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
fragmentOnMap = (FragmentOnMap)getFragmentManager().findFragmentById(R.id.fragment_bottom);
getFragmentManager().beginTransaction().hide(fragmentOnMap);
}
@Override
public void onMapReady(GoogleMap googleMap) {
//Get Last Known Location and convert into Current Longitute and Latitude
final LocationManager mlocManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
final Location currentGeoLocation = mlocManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
double currentLat = currentGeoLocation.getLatitude();
double currentLon = currentGeoLocation.getLongitude();
LatLng currentLatLng = new LatLng(currentLat,currentLon);
//Toast.makeText(this,"Cur Lat" +currentLat+"Lon"+currentLon,Toast.LENGTH_LONG).show();
// Get JSON String and Break it down into individual nodes
//double x=_location.getLatitude();
//double y=_location.getLongitude();
json_string = getIntent().getExtras().getString("JSON_DTA");
LatLng latLng = null;
try {
int count = 0;
//jsonObject = new JSONObject(json_string);
jsonArray = new JSONArray(json_string);
while (count < jsonArray.length()) {
JSONObject JO = jsonArray.getJSONObject(count);
_id = JO.getInt("id");
_doctorname = JO.getString("doctorname");
_doclat = JO.getString("latitude");
_doclong = JO.getString("longitude");
count++;
Double d = Double.parseDouble(_doclat);
Double e = Double.parseDouble(_doclong);
latLng = new LatLng(d, e);
DecimalFormat df = new DecimalFormat("####0.0");
DistanceBetweenPoints distanceBetweenPoints = new DistanceBetweenPoints();
double distance = distanceBetweenPoints.CalculationByDistance(currentLatLng,latLng);
double distanceThreshHold = 7 ;
if(distance < distanceThreshHold )
{
mMap = googleMap;
mMap.setOnInfoWindowClickListener(this);
MarkerOptions _markeroptions = new MarkerOptions()
.position(latLng)
.title(_doctorname+": " + df.format(distance) + " KM" )
.icon(BitmapDescriptorFactory.fromResource(R.drawable.smallest_logo));
mMap.addMarker(_markeroptions);
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
}
else
{
mMap = googleMap;
}
}
} catch (JSONException e) {
e.printStackTrace();
}
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
} else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(@Nullable Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.draggable(true);
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mMap.addMarker(markerOptions);
// Toast.makeText(this, "Current" + latLng, Toast.LENGTH_LONG).show();
String tag = null;
Log.d(tag, "lon: " + location.getLongitude() + " ----- lat: " + location.getLatitude());
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
public boolean checkLocationPermission(){
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an expanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// Permission was granted.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
// other 'case' lines to check for other permissions this app might request.
//You can add here other case statements according to your requirement.
}
}
您的帮助将不胜感激.谢谢.
Your help will much appreciated. Thank you.
推荐答案
在 ImageView 下放置一个带有标记图标的地图将是最好的方法(只是一个框架布局，在下面放置您的地图片段并且您的标记图像位于顶部应该工作).然后您可以使用 OnCameraIdleListener ，它会在地图移动结束时接收回调.因此，只需将 OnCameraIdleListener 的实例设置到您的地图上，以侦听移动回调，如下所示:
Having a map under an ImageView with your marker icon would be the best way to go here (just a framelayout with your map fragment under and your marker image centered on top should work). Then you can use an OnCameraIdleListener which would receive a callback when the map movement has ended. So just set an instance of OnCameraIdleListener to your map to listen for movement callbacks like so:
map.setOnCameraIdleListener(new GoogleMap.OnCameraIdleListener() {
@Override
public void onCameraIdle() {
//get latlng at the center by calling
LatLng midLatLng = map.getCameraPosition().target;
}
});
这篇关于Android:拖动地图，同时将标记保持在中心的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！