Question

我正试图从头开始编写一个GPS追踪器，但它刚开始时就失败了。

由于某种原因，以下代码给出了IllegalArgumentException：无效的侦听器：null。

mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mLocationManager.getProvider(LocationManager.GPS_PROVIDER);
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, mLocationListener);

mLocationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
            Log.i(TAG,"There is some noticeable movement");
        }

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

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

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

任何线索？

Answer 1

因为在这条线上

mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, mLocationListener);

mLocationListener是null。在requestLocationUpdates`之前初始化它。

mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mLocationManager.getProvider(LocationManager.GPS_PROVIDER);

mLocationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
            Log.i(TAG,"There is some noticeable movement");
        }

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

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

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // Auto-generated method stub
        }
}
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, mLocationListener);

Answer 2

更改代码，

mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mLocationManager.getProvider(LocationManager.GPS_PROVIDER);


mLocationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
            Log.i(TAG,"There is some noticeable movement");
        }

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

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

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

mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, mLocationListener);

ANDROID GPS /无效的听众

2 个答案: