Android LocationListener 不起作用

Question

我写了这段代码，但是 MyLocationListener 类不起作用。当我像“找我”这样的短信时，代码必须给我大概的位置，但它什么也没做。这里有什么问题吗？

public class SMSReceiver extends BroadcastReceiver {

    private LocationManager lm;
    private LocationListener locationlistener;
    private String senderTel;

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub

        // get the sms
        Bundle bundle = intent.getExtras();
        SmsMessage[] msgs = null;
        String str = "";

        if (bundle != null) {
            senderTel = "";

            Object[] pdus = (Object[]) bundle.get("pdus");
            msgs = new SmsMessage[pdus.length];
            for (int i = 0; i < msgs.length; i++) {

                msgs[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
                if (i == 0) {
                    senderTel = msgs[i].getOriginatingAddress();
                }

                str += msgs[i].getMessageBody().toString();

            }

            if (str.startsWith("Find me")) {
                // ---use the LocationManager class to obtain locations data---
                lm = (LocationManager) context
                        .getSystemService(Context.LOCATION_SERVICE);

                // ---request location updates---
                locationlistener = new MyLocationListener();
                lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
                        60000, 1000, locationlistener);
                // ---abort the broadcast; SMS messages won’t be broadcasted---



                this.abortBroadcast();
            }
        }

    }

    private class MyLocationListener implements LocationListener {

        @Override
        public void onLocationChanged(Location loc) {
            // TODO Auto-generated method stub
            if (loc != null) {
                // ---send a SMS containing the current location---

                SmsManager sms = SmsManager.getDefault();
                sms.sendTextMessage(senderTel, null,
                        "http://maps.google.com/maps?q=" + loc.getLatitude()
                                + "," + loc.getLongitude(), null, null);

                // ---stop listening for location changes---
                lm.removeUpdates(locationlistener);
            }
        }

        @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

        }

    }

}

Answer 1

很可能它没有按照您的预期运行，因为您没有以正确的方式对其进行测试。据我了解，您希望立即从 LocationProvider 获取位置，但这不是它的工作方式。

lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
         60000, 1000, locationlistener);

上面您要求 LocationProvider 在满足两个条件时更新监听器:当前和上一次更新之间耗时 >= 1 分钟且行驶距离 >= 1 公里。因此 LocationProvider 将根据这些条件更新监听器，但是如文档所述:

The location update interval can be controlled using the minTime parameter. 
The elapsed time between location updates will never be less than minTime, 
although it can be more depending on the Location Provider implementation 
and the update interval requested by other applications. 

和:

The minDistance parameter can also be used to control the frequency of location 
updates. If it is greater than 0 then the location provider will only send your 
application an update when the location has changed by at least minDistance meters

此外，您不会像预期的那样立即收到第一个更新。再次来自文档:

It may take a while to receive the first location update.

Application类中有一个方法getLastKnownLocation()它提供可用工具 (GPS/Wifi/GSM) 提供的最后位置。我相信这就是您要找的。