就像有人在我测试 nexus s(4.0.4 with google play service available) 和 avd (4.2.2 with google api) 之前遇到的问题一样，在这两种情况下 locationclientgetLastLocation()总是 return null。
public class MainActivity extends Activity implements LocationListener,
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener {
private LocationClient mLocationClient;
private LocationRequest mLocationRequest;
boolean mUpdatesRequested = false;
boolean mConnected = false;
SharedPreferences mPrefs;
SharedPreferences.Editor mEditor;
private TextView mText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mText = (TextView) findViewById(R.id.text);
mLocationRequest = LocationRequest.create();
mLocationRequest
.setInterval(LocationUtils.UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest
.setFastestInterval(LocationUtils.FAST_INTERVAL_CEILING_IN_MILLISECONDS);
mUpdatesRequested = false;
mPrefs = getSharedPreferences(LocationUtils.SHARED_PREFERENCES,
Context.MODE_PRIVATE);
mEditor = mPrefs.edit();
mLocationClient = new LocationClient(this, this, this);
}
@Override
public void onStart() {
super.onStart();
/*
* Connect the client. Don't re-start any requests here; instead, wait
* for onResume()
*/
mLocationClient.connect();
}
@Override
protected void onResume() {
super.onResume();
// If the app already has a setting for getting location updates, get it
if (mPrefs.contains(LocationUtils.KEY_UPDATES_REQUESTED)) {
mUpdatesRequested = mPrefs.getBoolean(
LocationUtils.KEY_UPDATES_REQUESTED, false);
// Otherwise, turn off location updates until requested
} else {
mEditor.putBoolean(LocationUtils.KEY_UPDATES_REQUESTED, false);
mEditor.commit();
}
}
@Override
public void onStop() {
// If the client is connected
if (mLocationClient.isConnected()) {
stopPeriodicUpdates();
}
// After disconnect() is called, the client is considered "dead".
mLocationClient.disconnect();
super.onStop();
}
@Override
public void onPause() {
// Save the current setting for updates
mEditor.putBoolean(LocationUtils.KEY_UPDATES_REQUESTED,
mUpdatesRequested);
mEditor.commit();
super.onPause();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void getLocation(View v) {
// If Google Play Services is available
if (isGooglePlayServicesAvailable()) {
if (!mConnected)
mText.setText("location client is not connected to service yet");
else {
// Get the current location
Location currentLocation = mLocationClient.getLastLocation();
// Display the current location in the UI
mText.setText(LocationUtils.getLocationString(currentLocation));
}
}
}
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(LocationUtils.APPTAG, "google play service is available");
// Continue
return true;
// Google Play services was not available for some reason
} else {
// Display an error dialog
Dialog dialog = GooglePlayServicesUtil.getErrorDialog(resultCode,
this, 0);
if (dialog != null) {
Log.e(LocationUtils.APPTAG,
"google play service is unavailable");
}
return false;
}
}
private void stopPeriodicUpdates() {
mLocationClient.removeLocationUpdates(this);
// mConnectionState.setText(R.string.location_updates_stopped);
}
@Override
public void onConnectionFailed(ConnectionResult arg0) {
mConnected = false;
Log.d(LocationUtils.APPTAG, "connection failed");
}
@Override
public void onConnected(Bundle arg0) {
mConnected = true;
Log.d(LocationUtils.APPTAG,
"location client connected to the location server");
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, 0, 0,
new android.location.LocationListener() {
@Override
public void onStatusChanged(String provider, int status,
Bundle extras) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onProviderDisabled(String provider) {}
@Override
public void onLocationChanged(final Location location) {
}
});
Log.d(LocationUtils.APPTAG, "done trying to get location");
}
@Override
public void onDisconnected() {
// TODO Auto-generated method stub
mConnected = false;
Log.d(LocationUtils.APPTAG,
"location client disconnected from the location server");
}
@Override
public void onLocationChanged(Location arg0) {}
}
其中大部分来自谷歌给出的例子。在上面的代码中，hava 尝试了这样的方法：
LocationRequest request = LocationRequest.create();
request.setNumUpdates(1);
mLocationClient.requestLocationUpdates(request, this);
和
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, 0, 0,
new android.location.LocationListener() {
@Override
public void onStatusChanged(String provider, int status,Bundle extras) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onProviderDisabled(String provider) {}
@Override
public void onLocationChanged(final Location location) {}
});
在onConnected()打电话之前getLastLocation()，但仍然没有运气。哪里出错了，先谢谢了。