Android LocationServices.FusedLocationApi.getLastLocation 返回 "null"

Question

我已经在其他线程中阅读了该问题的解决方案，但我似乎不明白为什么它会返回 null。我使用了谷歌开发者网站提供的相同 fragment :https://developer.android.com/training/location/retrieve-current.html

我在 Activity 中使用以下代码来获取用户的当前位置:

public class MainActivity extends Activity implements ConnectionCallbacks, OnConnectionFailedListener {
protected GoogleApiClient mGoogleApiClient;
protected Location mLastLocation;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    buildGoogleApiClient();
}
@Override
protected void onStart() {
    super.onStart();
    mGoogleApiClient.connect();
}
protected synchronized void buildGoogleApiClient() {
    mGoogleApiClient = new GoogleApiClient.Builder(this)
    .addConnectionCallbacks(this)
    .addOnConnectionFailedListener(this)
    .addApi(LocationServices.API)
    .build();
}
@Override
public void onConnected(Bundle connectionHint) {
    mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
            mGoogleApiClient);
    if (mLastLocation != null) {
        mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
        mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
    }
}

如果“mLastLocation”始终为空，我们如何编写代码来获取用户的当前位置？

Answer 1

文档说明(在文章的底部):

The location object returned may be null in rare cases when the location is not available.

当设备禁用定位服务或设备处于飞行模式时，可能会发生这种情况。当长时间未请求某个位置时，它似乎也会发生。