Question

我创建了以下代码，只需获取最新的纬度和经度，无需用户打开GPS，只需依靠wifi或网络进行定位。在运行应用程序时，它只返回Toast“The Lat is 0.0 and Long is 0.0”。我知道这应该有用，因为我在这里下载了示例代码：https://github.com/googlesamples/android-play-location/tree/master/BasicLocationSample，并且适合在我的代码中工作。

我怎样才能让它发挥作用？

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

    public static double lat;
    public static double lng;

    ViewPager viewPager = null;

    /**
     * Provides the entry point to Google Play services.
     */
    protected GoogleApiClient mGoogleApiClient;

    /**
     * Represents a geographical location.
     */
    protected Location mLastLocation;

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

        buildGoogleApiClient();

        String text = "The Lat is " + lat
                + " and Long is " + lng;

        Toast.makeText(getBaseContext(), text, Toast.LENGTH_LONG).show();

        };

        // Assign list to actionbar
        actionBar.setListNavigationCallbacks(aAdpt, null); // DEPRACATED

    } 


    /**
     * Builds a GoogleApiClient. Uses the addApi() method to request the LocationServices API.
     */
    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

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

    @Override
    protected void onStop() {
        super.onStop();
        if (mGoogleApiClient.isConnected()) {
            mGoogleApiClient.disconnect();
        }
    }

    /**
     * Runs when a GoogleApiClient object successfully connects.
     */
    @Override
    public void onConnected(Bundle connectionHint) {
        // Provides a simple way of getting a device's location and is well suited for
        // applications that do not require a fine-grained location and that do not need location
        // updates. Gets the best and most recent location currently available, which may be null
        // in rare cases when a location is not available.
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (mLastLocation != null) {
            lat = mLastLocation.getLatitude();
            lng = mLastLocation.getLongitude();
        } else {
            Toast.makeText(this,"No location detected", Toast.LENGTH_LONG).show();
        }
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        // Refer to the javadoc for ConnectionResult to see what error codes might be returned in
        // onConnectionFailed.

    }


    @Override
    public void onConnectionSuspended(int cause) {
        // The connection to Google Play services was lost for some reason. We call connect() to
        // attempt to re-establish the connection.

        mGoogleApiClient.connect();
    }
}

}

Answer 1

＆＃34; lat＆＃34;，＆＃34; lng＆＃34;，＆＃34; mLastLocation＆＃34;在执行onConnected（）之前，设置或有效。您需要了解此操作是异步 - 也就是说，该位置不会立即返回，但稍后会提供。如果您测试了是否＆＃34; mLastLocation＆＃34;这将是显而易见的。当你做吐司时，它是否为空。

Android无法检索位置

1 个答案: