随着位置更新，删除以前的标记

时间：2017-01-25 16:58:51

标签： android google-maps firebase firebase-realtime-database google-maps-markers

我在地图上放了一些标记。随着标记的位置发生变化，它会在地图上放置另一个标记，但保留最后一个标记，因为它会在地图上创建多个具有相同ID的标记。

我有办法将上一个标记清除为位置更新。

我正在从任何数组中的firebase数据库中检索位置更改。

这是我的代码：

import android.content.Intent;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.telephony.SmsManager;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.Map;

public class MapsActivity extends MainActivity implements    OnMapReadyCallback {
// flag for Internet connection status
Boolean isInternetPresent = false;

// Connection detector class
ConnectionDetector cd;

// Alert Dialog Manager
AlertDialogManager alert = new AlertDialogManager();

// GPS Location
GPSTracker gps;

Handler handler = new Handler();
Runnable refresh;


final int[] count = {0};

final ArrayList<String> locationData = new ArrayList<>();
final ArrayList<String> DriverInfo = new ArrayList<>();

public GoogleMap mMap;
public Marker marker;

MediaPlayer mediaPlayer;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            int id = item.getItemId();

            if (id == R.id.profile) {
                finish();
                startActivity(new Intent(MapsActivity.this, ProfileActivity.class));
            } else if (id == R.id.nearby) {
                finish();
                startActivity(new Intent(MapsActivity.this, NearbyActivity.class));
            } else if (id == R.id.notification) {
                finish();
                startActivity(new Intent(MapsActivity.this, NotificationActivity.class));
            } else if (id == R.id.setting) {
                finish();
                startActivity(new Intent(MapsActivity.this, SettingsActivity.class));
            } else if (id == R.id.faq) {
                finish();
                startActivity(new Intent(MapsActivity.this, FaqActivity.class));
            } else if (id == R.id.emergecy_contact) {
                finish();
                startActivity(new Intent(MapsActivity.this, EmergencyContactActivity.class));
            } else if (id == R.id.support) {
                finish();
                startActivity(new Intent(MapsActivity.this, SupportActivity.class));
            } else if (id == R.id.help) {
                finish();
                startActivity(new Intent(MapsActivity.this, HelpActivity.class));
            } else if (id == R.id.about_us) {
                finish();
                startActivity(new Intent(MapsActivity.this, AboutUsActivity.class));
            } else if (id == R.id.rate) {
                finish();
                startActivity(new Intent(MapsActivity.this, RateUsActivity.class));
            } else if (id == R.id.share) {
                finish();
                startActivity(new Intent(MapsActivity.this, ShareActivity.class));
            }

            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            drawer.closeDrawer(GravityCompat.START);
            return true;
        }
    });

    mediaPlayer = MediaPlayer.create(this, R.raw.demonstrative);

    cd = new ConnectionDetector(getApplicationContext());

    // Check if Internet present
    isInternetPresent = cd.isConnectingToInternet();
    if (!isInternetPresent) {
        // Internet Connection is not present
        alert.showAlertDialog(MapsActivity.this, "Internet Connection Error",
                "Please connect to working Internet connection", false);
        // stop executing code by return
        return;
    }

    // creating GPS Class object
    gps = new GPSTracker(this);

    // check if GPS location can get
    if (gps.canGetLocation()) {
        Log.d("Your Location", "latitude:" + gps.getLatitude() + ", longitude: " + gps.getLongitude());
    } else {
        // Can't get user's current location
        alert.showAlertDialog(MapsActivity.this, "GPS Status",
                "Couldn't get location information. Please enable GPS",
                false);
        // stop executing code by return
        return;
    }
    // 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);


    //Retrive data from firebase

    final FirebaseDatabase database = FirebaseDatabase.getInstance();
    final DatabaseReference myRef = database.getReference().child("users");


    myRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            collectLocation((Map<String, Object>) dataSnapshot.getValue());
            collectdriverInfo((Map<String, Object>) dataSnapshot.getValue());
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }

    });
}


//Retrieve location from database
public void collectLocation(Map<String, Object> users) {
    for (Map.Entry<String, Object> entry : users.entrySet()) {
        //Get user map
        Map singleUser = (Map) entry.getValue();
        //Get phone field and append to list
        locationData.add((String) singleUser.get("location"));

        count[0]++;

    }

    System.out.println("Location: " + locationData.toString());
    System.out.println("My count is: " + count[0]);
}

//Retrive driver info from database
public void collectdriverInfo(Map<String, Object> users) {
    final String[] userName = new String[count[0]];
    final String[] userContact = new String[count[0]];

    final double[] latitude = new double[count[0]];
    final double[] longitude = new double[count[0]];


    for (Map.Entry<String, Object> entry : users.entrySet()) {
        //Get user map
        Map singleUser = (Map) entry.getValue();
        //Get phone field and append to list
        DriverInfo.add((String) singleUser.get("driverInfo"));
    }
    System.out.println("Driver Information: " + DriverInfo.toString());


    //Convert location string to double
    int j = 0;
    for (String loc : locationData) {
        System.out.println("LocationMMdm" + loc);
        String[] Location = loc.split(",");
        latitude[j] = Double.parseDouble(Location[0]);
        longitude[j] = Double.parseDouble(Location[1]);
        System.out.println("lat: " + latitude[0] + " " + "log: " + longitude[0]);

        j++;
    }

    //Split driver info and add marker on map
    int i = 0;
    for (String data : DriverInfo) {
        System.out.println("datainfo " + data);
        String[] singleEntry = data.split(",");
        userName[i] = singleEntry[0];
        userContact[i] = singleEntry[1];

        mMap.addMarker(new MarkerOptions().position(new LatLng(latitude[i], longitude[i])).
                    title(userName[i]).
                    snippet(userContact[i]).
                    flat(true).
                    alpha(0.9f).
                    anchor(0.5f, 0.5f).
                    rotation((0.0f)).
                    icon(BitmapDescriptorFactory.fromResource(R.drawable.markeramb)));
            i++;
    }


    mMap.setOnInfoWindowLongClickListener(new GoogleMap.OnInfoWindowLongClickListener() {
        @Override
        public void onInfoWindowLongClick(Marker marker) {
            String phoneno = marker.getSnippet();
            double myLat = gps.getLatitude();
            double myLog = gps.getLongitude();
            String title = marker.getTitle();
            String msg = myLat + ", " + myLog;

            try {
                SmsManager smsManager = SmsManager.getDefault();
                smsManager.sendTextMessage(phoneno, null, msg, null, null);

                View view = findViewById(android.R.id.content);
                Snackbar.make(view, "Message Sent", Snackbar.LENGTH_LONG).show();

                mediaPlayer.start();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });

    //Call to the ambulance driver
    mMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
        @Override
        public void onInfoWindowClick(Marker marker) {
            try {
                String uri = "tel:" + marker.getSnippet();
                if (marker.getSnippet() == null) {
                    alert.showAlertDialog(MapsActivity.this, "Not Present",
                            "Contact no. not available", false);
                } else {
                    finish();
                    Intent callIntent = new Intent(Intent.ACTION_CALL, Uri.parse(uri));
                    startActivity(callIntent);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    });
    System.out.println("Users name are: " + userName.toString());
    System.out.println("Users count is: " + userContact.toString());
    System.out.println("Count is:" + count[0]);
}



@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.setMyLocationEnabled(true);
    double myLatitude = gps.getLatitude();
    double myLongitude = gps.getLongitude();
    LatLng latLng = new LatLng(myLatitude, myLongitude);
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));
}


@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
        finish();
        startActivity(new Intent(MapsActivity.this, MainActivity.class));
    }
  }
}

1 个答案:

答案 0 :(得分：0)

以下内容可帮助您删除标记 

if (destnationMarker != null) {

   destnationMarker.remove();
   mMap.clear();
   destnationMarker = null;

}
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