如何在Google Maps Android API v2中将相机直接移动到当前位置？

Question

不点击任何按钮,如何直接获取当前位置并将相机移动到它.
另外,我发现地图右上方有一个按钮.单击它时,它将转到当前位置.单击该按钮时如何获取返回的位置？

Answer 1

确保您拥有以下权限:

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

然后进行一些活动并注册LocationListener

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

上述答案不符合谷歌文档在Google API v2中提到的位置跟踪功能.

我只是按照官方教程进行了操作,最后得到了这个类,它正在获取当前位置,并在我得到它的同时将地图居中.

您可以扩展此类以使LocationReciever定期更新位置.我刚刚在api level 7上执行了这段代码

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

在这里.

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

我正在解释,如何获取当前位置并直接移动到相机到当前位置,假设您已经实现了map-v2.有关详细信息,请参阅官方文档.

在gradle中添加位置服务

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

在清单文件中添加位置权限

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

确保要求RunTimePermission.我正在使用Ask-Permission.它易于使用.

现在参考下面的代码来获取当前位置并将其显示在地图上.

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());
        }
}

当用户授予位置权限时调用上述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());
        }
    }