重新过渡当我点击按钮（例如/ ie Like Intent从当前活动到自我活动）

Question

基本上我在谷歌地图上工作，我有谷歌地图活动和用户点击任何我正在添加的Google地图的地方标记点击这个按钮上的一个按钮单击我将此标记位置并将其放到我的Firebase数据库。我的完整代码正在工作，但问题是，当我单击将标记latlang到Firebase的按钮时，我的latlang值成功更新，我的地图Activity被重新转换（例如/ ie像从当前Activity到自我Activity的Intent），因为我的地图被重新加载，并且我在屏幕上丢失了标记。

这里是我的Java代码：

import android.support.annotation.Nullable; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.content.pm.PackageManager; 
import android.location.Location; 
import android.support.v4.app.ActivityCompat; 
import android.support.v4.content.ContextCompat; 
import android.view.View; 
import android.widget.Button; 
import android.widget.Toast; 
import com.firebase.client.Firebase; 
import com.google.android.gms.common.api.GoogleApiClient; 
import com.google.android.gms.location.LocationServices; 
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.LatLng; 
import com.google.android.gms.maps.model.Marker; 
import com.google.android.gms.maps.model.MarkerOptions; 

public class PickUpActivity extends AppCompatActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, View.OnClickListener, GoogleMap.OnMapClickListener { 
    private static final int PERMISSION_REQUEST_CODE = 1; 
    public double marker_latitude; 
    public double marker_longitude; 
    private GoogleMap mMap; 
    private GoogleApiClient googleApiClient; 
    private Marker marker; 
    private double latitude; 
    private double longitude; 
    private Button btn; 
    private Bus bus; 
    private Firebase ref; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_pick_up); 
     Firebase.setAndroidContext(this); 
     btn = (Button) findViewById(R.id.btn_pick); 
     ref = new Firebase(Config.FIREBASE_URL); 
     bus = new Bus(); 
     SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
       .findFragmentById(R.id.map); 
     mapFragment.getMapAsync(this); 
     mMap = mapFragment.getMap(); 
     googleApiClient = new GoogleApiClient.Builder(this) 
       .addConnectionCallbacks(this) 
       .addApi(LocationServices.API) 
       .build(); 

     btn.setOnClickListener(this); 
     mMap.setOnMapClickListener(this); 
    } 


    @Override 
    public void onMapReady(GoogleMap googleMap) { 
     mMap = googleMap; 
    } 

    @Override 
    public void onConnected(@Nullable Bundle bundle) { 
     getCurrentLocation(); 

    } 

    @Override 
    public void onConnectionSuspended(int i) { 

    } 

    @Override 
    protected void onStart() { 
     googleApiClient.connect(); 
     super.onStart(); 
    } 

    @Override 
    protected void onStop() { 
     googleApiClient.disconnect(); 
     super.onStop(); 
    } 

    private void getCurrentLocation() { 
     if (!checkPermission()) { 
      requestPermission(); 
     } 

     Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient); 
     if (location != null) { 

      longitude = location.getLongitude(); 
      latitude = location.getLatitude(); 

      moveMap(); 
     } 
    } 

    private void moveMap() { 
     LatLng latLng = new LatLng(latitude, longitude); 
     mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 
     mMap.animateCamera(CameraUpdateFactory.zoomTo(15)); 
    } 

    private boolean checkPermission() { 
     int result = ContextCompat.checkSelfPermission(PickUpActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION); 
     if (result == PackageManager.PERMISSION_GRANTED) { 
      return true; 
     } else { 
      return false; 
     } 
    } 

    private void requestPermission() { 

     if (ActivityCompat.shouldShowRequestPermissionRationale(PickUpActivity.this, android.Manifest.permission.ACCESS_FINE_LOCATION)) { 
      Toast.makeText(PickUpActivity.this, "GPS permission allows us to access location data. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show(); 
     } else { 
      ActivityCompat.requestPermissions(PickUpActivity.this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_REQUEST_CODE); 
     } 
    } 

    @Override 
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) { 
     switch (requestCode) { 
      case PERMISSION_REQUEST_CODE: 
       if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
        getCurrentLocation(); 
       } else { 

       } 
       break; 
     } 
    } 

    @Override 
    public void onClick(View v) { 
     if (v == btn) { 
      if (marker == null) { 
       Toast.makeText(PickUpActivity.this, "Please Select Any Place", Toast.LENGTH_SHORT).show(); 
      } else { 
       bus.setlatitude(marker_latitude); 
       bus.setlongitude(marker_longitude); 
       ref.child("school1").child("bus1").child("parents").child("parent01").child("pickuppoint").setValue(bus); 
       Toast.makeText(PickUpActivity.this, "Pick Up Point Set", Toast.LENGTH_SHORT).show(); 
      } 
     } 
    } 

    @Override 
    public void onMapClick(LatLng latLng) { 
     mMap.clear(); 
     marker = mMap.addMarker(new MarkerOptions() 
       .position(latLng) //setting position 
       .draggable(true) //Making the marker draggable 
       .title("" + latLng)); 
     marker_latitude = latLng.latitude; 
     marker_longitude = latLng.longitude; 
    } 
} 

在分析过程中，我发现问题在下面的代码：

bus.setlatitude(marker_latitude); 
bus.setlongitude(marker_longitude); 
    ref.child("school1").child("bus1").child("parents").child("parent01").child("pickuppoint").setValue(bus); 

如果我把一些静态值上bus.setlatitude()和bus.setlongitude没有再发生转变。我不知道我做错了什么，以及这个问题的解决方案是什么。

Answer 1

如果用户点击地图中的地图将被清除：mMap.clear();

@Override 
public void onMapClick(LatLng latLng) { 

    mMap.addMarker(new MarkerOptions() 
      .position(latLng) //setting position 
      .draggable(true) //Making the marker draggable 
      .title(""+latLng)); 
    marker_latitude = latLng.latitude; 
    marker_longitude= latLng.longitude; 

}