无法在谷歌地图中获取当前位置

Question

我无法通过以下方式获取当前位置。这些代码是从网络上的一些教程中学习的，我不知道标记仍然在同一位置会发生什么。我是android新手，请帮助T_T

这是 MapsActivity.java 中的代码。

import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
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.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity implements
    GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener,
    LocationListener {

public static final String TAG = MapsActivity.class.getSimpleName();

/*
 * 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;

private GoogleMap mMap; // Might be null if Google Play services APK is not available.

private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;

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

    if (mGoogleApiClient == null) {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    // Create the LocationRequest object
    mLocationRequest = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
            .setInterval(10 * 1000)        // 10 seconds, in milliseconds
            .setFastestInterval(1 * 1000); // 1 second, in milliseconds
}

@Override
protected void onResume() {
    super.onResume();
    setUpMapIfNeeded();
    mGoogleApiClient.connect();
}

@Override
protected void onPause() {
    super.onPause();

    if (mGoogleApiClient.isConnected()) {
        LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
        mGoogleApiClient.disconnect();
    }
}

/**
 * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
 * installed) and the map has not already been instantiated.. This will ensure that we only ever
 * call {@link #setUpMap()} once when {@link #mMap} is not null.
 * <p/>
 * If it isn't installed {@link SupportMapFragment} (and
 * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
 * install/update the Google Play services APK on their device.
 * <p/>
 * A user can return to this FragmentActivity after following the prompt and correctly
 * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
 * have been completely destroyed during this process (it is likely that it would only be
 * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
 * method in {@link #onResume()} to guarantee that it will be called.
 */
private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}

/**
 * This is where we can add markers or lines, add listeners or move the camera. In this case, we
 * just add a marker near Africa.
 * <p/>
 * This should only be called once and when we are sure that {@link #mMap} is not null.
 */
private void setUpMap() {
    mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));

}

private void handleNewLocation(Location location) {
    Log.d(TAG, location.toString());

    double currentLatitude = location.getLatitude();
    double currentLongitude = location.getLongitude();

    LatLng latLng = new LatLng(currentLatitude, currentLongitude);

    mMap.addMarker(new MarkerOptions().position(new LatLng(currentLatitude, currentLongitude)).title("Current Location"));
    MarkerOptions options = new MarkerOptions()
            .position(latLng)
            .title("I am here!");
    mMap.addMarker(options);
    mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
}

@Override
public void onConnected(Bundle bundle) {

    Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (location == null) {
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
    }
    else {
        handleNewLocation(location);
    }
}

@Override
public void onConnectionSuspended(int i) {
    Log.i(TAG, "Location services suspended. Please reconnect.");
}

@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 {
        /*
         * If no resolution is available, display a dialog to the
         * user with the error.
         */
        Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
    }
}

@Override
public void onLocationChanged(Location location) {
    handleNewLocation(location);
}

}

这是 Android Manifest 中的代码。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.tanghoiyan.mapapp">


<!--
     The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
     Google Maps Android API v2, but you must specify either coarse or fine
     location permissions for the 'MyLocation' functionality. 
-->

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

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <!--
         The API key for Google Maps-based APIs is defined as a string resource.
         (See the file "res/values/google_maps_api.xml").
         Note that the API key is linked to the encryption key used to sign the APK.
         You need a different API key for each encryption key, including the release key that is used to
         sign the APK for publishing.
         You can define the keys for the debug and release targets in src/debug/ and src/release/. 
    -->
    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_maps_key" />

    <activity
        android:name=".MapsActivity"
        android:label="@string/title_activity_maps">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>
</manifest>

Answer 1

请在清单中添加

<uses-permission android:name="android.permission.INTERNET" 
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<permission android:name="com.example.tanghoiyan.mapapp.permission.MAPS_RECEIVE" android:protectionLevel="signature"/>
<uses-feature android:glEsVersion="0x00020000" android:required="true" />

然后再试一次。

注意：如果您使用的是 Android 6.+，您可以实时检查位置权限。

Answer 2

将.setNumUpdates(1); 添加到您的 mLocationRequest 中，这样您只会收到一次位置信息。
以下代码检查 GPS 位置更新所需的权限，并启动您已有的请求。我在按钮单击事件上使用代码，它的工作方式与预期一样，当然我第一次使用它需要一些时间来获取位置，但这是 GPS。

protected void startLocationUpdates() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
        LocationServices.FusedLocationApi.requestLocationUpdates(
                mGoogleApiClient, mLocationRequest, this);
    }
}

您是否检查了您是否在onConnectedfunction 中获得了 Location 或者它是否为空？