如何直接將相機移至Google Maps Android API v2中的當前位置？

Question

不點擊任何按鈕，如何直接獲取當前位置並將相機移動到該位置。
此外，我發現地圖右上方有一個按鈕。點擊它時，它會轉到當前位置。如何獲取點擊該按鈕時返回的位置？

Answer 1

請確保您擁有這些權限：

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/> 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> 

然後做一些活動和註冊LocationListener的

package com.example.location; 

import android.content.Context; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.os.Bundle; 
import android.view.View; 
import com.actionbarsherlock.app.SherlockFragmentActivity; 
import com.google.android.gms.maps.CameraUpdate; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.SupportMapFragment; 
import com.google.android.gms.maps.model.LatLng; 

public class LocationActivity extends SherlockFragmentActivity implements LocationListener  { 
private GoogleMap map; 
private LocationManager locationManager; 
private static final long MIN_TIME = 400; 
private static final float MIN_DISTANCE = 1000; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.map); 
    map = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); 

    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME, MIN_DISTANCE, this); //You can also use LocationManager.GPS_PROVIDER and LocationManager.PASSIVE_PROVIDER   
} 

@Override 
public void onLocationChanged(Location location) { 
    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude()); 
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 10); 
    map.animateCamera(cameraUpdate); 
    locationManager.removeUpdates(this); 
} 

@Override 
public void onStatusChanged(String provider, int status, Bundle extras) { } 

@Override 
public void onProviderEnabled(String provider) { } 

@Override 
public void onProviderDisabled(String provider) { } 
} 

map.xml

<?xml version="1.0" encoding="utf-8"?> 
<fragment xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/map" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
class="com.google.android.gms.maps.SupportMapFragment"/> 

Answer 2

以上回答沒有根據Google Doc推薦Google API a v2中的位置跟蹤功能。

我只是跟着官方的教程，並結束了與這個類是獲取當前位置，並儘快圍繞它的地圖，因爲我明白了。

你可以擴展這個類有LocationReciever有周期性位置更新。 我只是在執行API級驗證碼7

http://developer.android.com/training/location/retrieve-current.html

在這裏不言而喻。

import android.app.Activity; 
import android.app.Dialog; 
import android.content.Intent; 
import android.content.IntentSender; 
import android.location.Location; 
import android.os.Bundle; 
import android.support.v4.app.DialogFragment; 
import android.support.v4.app.FragmentActivity; 
import android.util.Log; 
import android.widget.Toast; 

import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesClient; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.location.LocationClient; 
import com.google.android.gms.maps.CameraUpdate; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener; 
import com.google.android.gms.maps.SupportMapFragment; 
import com.google.android.gms.maps.model.LatLng; 


public class MainActivity extends FragmentActivity implements 
    GooglePlayServicesClient.ConnectionCallbacks, 
    GooglePlayServicesClient.OnConnectionFailedListener{ 

private SupportMapFragment mapFragment; 
private GoogleMap map; 
private LocationClient mLocationClient; 
/* 
* Define a request code to send to Google Play services 
* This code is returned in Activity.onActivityResult 
*/ 
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000; 

// Define a DialogFragment that displays the error dialog 
public static class ErrorDialogFragment extends DialogFragment { 

    // Global field to contain the error dialog 
    private Dialog mDialog; 

    // Default constructor. Sets the dialog field to null 
    public ErrorDialogFragment() { 
     super(); 
     mDialog = null; 
    } 

    // Set the dialog to display 
    public void setDialog(Dialog dialog) { 
     mDialog = dialog; 
    } 

    // Return a Dialog to the DialogFragment. 
    @Override 
    public Dialog onCreateDialog(Bundle savedInstanceState) { 
     return mDialog; 
    } 
} 

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

    mLocationClient = new LocationClient(this, this, this); 

    mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)); 
    map = mapFragment.getMap(); 

    map.setMyLocationEnabled(true); 

} 

/* 
* Called when the Activity becomes visible. 
*/ 
@Override 
protected void onStart() { 
    super.onStart(); 
    // Connect the client. 
    if(isGooglePlayServicesAvailable()){ 
     mLocationClient.connect(); 
    } 

} 

/* 
* Called when the Activity is no longer visible. 
*/ 
@Override 
protected void onStop() { 
    // Disconnecting the client invalidates it. 
    mLocationClient.disconnect(); 
    super.onStop(); 
} 

/* 
* Handle results returned to the FragmentActivity 
* by Google Play services 
*/ 
@Override 
protected void onActivityResult(
       int requestCode, int resultCode, Intent data) { 
    // Decide what to do based on the original request code 
    switch (requestCode) { 

     case CONNECTION_FAILURE_RESOLUTION_REQUEST: 
      /* 
      * If the result code is Activity.RESULT_OK, try 
      * to connect again 
      */ 
      switch (resultCode) { 
       case Activity.RESULT_OK: 
        mLocationClient.connect(); 
        break; 
      } 

    } 
} 

private boolean isGooglePlayServicesAvailable() { 
    // Check that Google Play services is available 
    int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this); 
    // If Google Play services is available 
    if (ConnectionResult.SUCCESS == resultCode) { 
     // In debug mode, log the status 
     Log.d("Location Updates", "Google Play services is available."); 
     return true; 
    } else { 
     // Get the error dialog from Google Play services 
     Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(resultCode, 
                               this, 
                               CONNECTION_FAILURE_RESOLUTION_REQUEST); 

     // If Google Play services can provide an error dialog 
     if (errorDialog != null) { 
      // Create a new DialogFragment for the error dialog 
      ErrorDialogFragment errorFragment = new ErrorDialogFragment(); 
      errorFragment.setDialog(errorDialog); 
      errorFragment.show(getSupportFragmentManager(), "Location Updates"); 
     } 

     return false; 
    } 
} 

/* 
* Called by Location Services when the request to connect the 
* client finishes successfully. At this point, you can 
* request the current location or start periodic updates 
*/ 
@Override 
public void onConnected(Bundle dataBundle) { 
    // Display the connection status 
    Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show(); 
    Location location = mLocationClient.getLastLocation(); 
    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude()); 
    CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 17); 
    map.animateCamera(cameraUpdate); 
} 

/* 
* Called by Location Services if the connection to the 
* location client drops because of an error. 
*/ 
@Override 
public void onDisconnected() { 
    // Display the connection status 
    Toast.makeText(this, "Disconnected. Please re-connect.", 
      Toast.LENGTH_SHORT).show(); 
} 

/* 
* Called by Location Services if the attempt to 
* Location Services fails. 
*/ 
@Override 
public void onConnectionFailed(ConnectionResult connectionResult) { 
    /* 
    * Google Play services can resolve some errors it detects. 
    * If the error has a resolution, try sending an Intent to 
    * start a Google Play services activity that can resolve 
    * error. 
    */ 
    if (connectionResult.hasResolution()) { 
     try { 
      // Start an Activity that tries to resolve the error 
      connectionResult.startResolutionForResult(
        this, 
        CONNECTION_FAILURE_RESOLUTION_REQUEST); 
      /* 
      * Thrown if Google Play services canceled the original 
      * PendingIntent 
      */ 
     } catch (IntentSender.SendIntentException e) { 
      // Log the error 
      e.printStackTrace(); 
     } 
    } else { 
     Toast.makeText(getApplicationContext(), "Sorry. Location services not available to you", Toast.LENGTH_LONG).show(); 
    } 
} 

} 

Answer 3

我解釋瞭如何獲取當前位置，並假設您已經實現了map-v2，直接移動到相機到當前位置。欲瞭解更多詳情，您可以參考official doc。

添加位置服務的Gradle中

implementation "com.google.android.gms:play-services-location:11.0.1" 

添加位置的權限清單文件

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 

確保你問的RuntimePermission。我正在使用Ask-Permission。它易於使用。

現在參考下面的代碼來獲取當前位置，並在地圖上顯示出來。

private FusedLocationProviderClient mFusedLocationProviderClient; 

@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     mFusedLocationProviderClient = LocationServices 
       .getFusedLocationProviderClient(getActivity()); 

} 

private void getDeviceLocation() { 
     try { 
      if (mLocationPermissionGranted) { 
       Task<Location> locationResult = mFusedLocationProviderClient.getLastLocation(); 
       locationResult.addOnCompleteListener(new OnCompleteListener<Location>() { 
        @Override 
        public void onComplete(@NonNull Task<Location> task) { 
         if (task.isSuccessful()) { 
          // Set the map's camera position to the current location of the device. 
          Location location = task.getResult(); 
          LatLng currentLatLng = new LatLng(location.getLatitude(), 
            location.getLongitude()); 
          CameraUpdate update = CameraUpdateFactory.newLatLngZoom(currentLatLng, 
            DEFAULT_ZOOM); 
          googleMap.moveCamera(update); 
         } 
        } 
       }); 
      } 
     } catch (SecurityException e) { 
      Log.e("Exception: %s", e.getMessage()); 
     } 
} 

當用戶授予上述getDeviceLocation()方法

private void updateLocationUI() { 
     if (googleMap == null) { 
      return; 
     } 
     try { 
      if (mLocationPermissionGranted) { 
       googleMap.setMyLocationEnabled(true); 
       googleMap.getUiSettings().setMyLocationButtonEnabled(true); 
       getDeviceLocation(); 
      } else { 
       googleMap.setMyLocationEnabled(false); 
       googleMap.getUiSettings().setMyLocationButtonEnabled(false); 
      } 
     } catch (SecurityException e) { 
      Log.e("Exception: %s", e.getMessage()); 
     } 
    }