使用带有 GPS 提供程序的 requestLocationUpdates 永远不会调用 onLocationChanged

Question

我正在开发一个应用程序，通过使用服务来跟踪用户的位置并将数据发送到后台的服务器。这是基于 GPS 的应用程序。当我的程序使用 GPS 提供程序调用 requestLocationUpdates 时，永远不会调用 onLocationChanged。但是，requestLocationUpdates 与我的应用程序上的网络提供商一起工作得很好。请看我的代码。

安卓版本：4.1.2 设备：Galaxy nexus S

Tracker.java

private void init() {
    locationListener = new MyLocationListener();
    mNM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    NOTIFICATION = R.string.local_service_started;
    arrivedStatus = false;
    activity = TrackerActivity.getAppActivity();
}

@Override
public void onCreate() {
    super.onCreate();
    init();
    Log.i(tag, "Start Tracking");
    showStartNotification();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Log.i("LocalService", "Received start id " + startId + ": " + intent);
    tripID = intent.getExtras().getInt("tripID") + "";
    locationInterval = intent.getExtras().getInt("locationInterval")
            * MILLISECONDS_PER_SECOND;
    //lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
    //      locationInterval, 0, locationListener);
    getLocation();
    return START_STICKY;
}

@Override
public void onDestroy() {
    super.onDestroy();
    Log.e("STOP_SERVICE", "Service has stopped");
    mNM.cancel(R.string.local_service_started);
    lm.removeUpdates(locationListener);
    stopSelf();
}

private void getLocation() {
    lm = (LocationManager) getApplicationContext().getSystemService(
            Context.LOCATION_SERVICE);

    // getting GPS status
    isGPSEnabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);

    // getting network status
    isNetworkEnabled = lm
            .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

    if (!isGPSEnabled && !isNetworkEnabled) {
        // no network provider is enabled
        Log.e(tag, "Non providers are enabled");
    } else {

        if (isGPSEnabled) {
            lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,
                    locationInterval, 0, locationListener);
            Log.d(tag, "GPS Enabled");
        }

        if (isNetworkEnabled) {
            if (lm == null) {
                lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
                        locationInterval, 0, locationListener);
                Log.d(tag, "Network Enabled");
            }
        }
    }
}

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

@SuppressWarnings("deprecation")
private void showStartNotification() {
    // In this sample, we'll use the same text for the ticker and the
    // expanded notification
    CharSequence text = getText(R.string.local_service_started);

    // Set the icon, scrolling text and timestamp
    Notification notification = new Notification(R.drawable.cameral, text,
            System.currentTimeMillis());

    // The PendingIntent to launch our activity if the user selects this
    // notification+
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
            new Intent(this, TrackerActivity.class), 0);

    // Set the info for the views that show in the notification panel.
    notification.setLatestEventInfo(this,
            getText(R.string.local_service_label), text, contentIntent);

    // Send the notification.
    mNM.notify(NOTIFICATION, notification);
}

/**
 * private void showStopSpecification() { CharSequence text =
 * getText(R.string.local_service_cancel); Notification notification = new
 * Notification(R.drawable.btn_save_dialog, text,
 * System.currentTimeMillis()); mNM.notify(NOTIFICATION, notification); }
 */

private void checkResult(JSONObject json) {
    try {
        if (json.getString(KEY_SUCCESS) != null) {
            String res = json.getString(KEY_SUCCESS);
            if (Integer.parseInt(res) == 1) {
                Log.v(tag, "Store data successfully");
                activity.findViewById(R.id.tracker_info)
                        .setBackgroundResource(R.color.blue4);
                if (json.getInt(ARRIVED_STATUS) == 1) {
                    setArrivedStatus(true);
                } else {
                    setArrivedStatus(false);
                }
            } else if (json.getString(KEY_ERROR).equals("1")) {
                // Error in login
                String error_msg = json.getString(KEY_ERROR_MSG);
                Log.e(tag, error_msg);
                setArrivedStatus(false);
            } else {
                Log.e(tag, "Something is wrong");
                setArrivedStatus(false);
            }
        } else {
            Log.e(tag, "Something is wrong");
            setArrivedStatus(false);
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

public void setArrivedStatus(boolean status) {
    arrivedStatus = status;
}

public boolean getArrivedStatus() {
    return arrivedStatus;
}

private class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location location) {
        // TODO Auto-generated method stub
        currentLat = location.getLatitude() + "";
        currentLng = location.getLongitude() + "";
        Log.v(tag, LOCATION_CHANGED + " lat=" + currentLat + ", lon="
                + currentLng);
        try {
            JSONObject json = new LogInfo().execute(
                    new String[] { tripID, currentLat, currentLng }).get();
            checkResult(json);
            if (getArrivedStatus() == true) {
                Log.v(tag, "User has arrived safely");
                onDestroy();
            }
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }

}

}

我也已经在我的清单中添加了权限

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

谢谢

Answer 1

当你调用这个函数时，你看到设备通知栏上的 GPS 图标了吗？如果是这样，这意味着它试图获取一个位置，而你只是在一个没有 GPS 接收的地方。

无论如何，你都可以使用谷歌的方式来获取位置，这里：https://developers.google.com/events/io/sessions/324498944

另外，什么是“Tracker”类？是服务吗？如果是这样，你不应该让它引用一个活动，因为它会导致内存泄漏。而是使用正确的绑定。

您还应该避免调用 "onDestroy" ，因为调用它并不会真正关闭您的服务。而是调用“stopSelf”，并确保没有绑定任何活动。

如果你愿意，我很久以前就问过这类问题（通过服务获取位置）here。