【发布时间】:2017-02-27 14:17:35
【问题描述】:
我编写了一个启动定位服务的应用程序,该服务使用 Intent 获取地址,并在该位置位于预定义半径之内和之外时弹出一个通知。 问题是当我试图破坏 MainAvtivity 时。我希望服务保持活动状态,但是当我销毁应用程序时,它会崩溃。
我的代码:
LocationService.java
public class LocationService extends Service {
private LocationManager mLocationManager;
private boolean inRange = false;
private boolean isNotificationPosted = false;
private DatabaseHelper db;
private ReportItem item;
private float lastKnownDistance;
private Location chosenLocation;
private static final long LOCATION_REFRESH_TIME = 10000;
private static final float LOCATION_REFRESH_DISTANCE = 10;
private static final int RADIUS = 100;
private static final float INITIAL_DISTANCE = 1000;
private LocationListener mLocationListener = new LocationListener() {
@Override
public void onLocationChanged(Location location)
{
float distance = location.distanceTo(chosenLocation);
if(!isNotificationPosted)
{
if (lastKnownDistance > distance) {
//Entering workplace radius
if (distance < RADIUS && !inRange) {
Log.i("Service", "in range with notification");
inRange = true;
item = new ReportItem();
makeNotification();
isNotificationPosted = true;
}
}
}
else
{
if (lastKnownDistance < distance) {
//Leaving workplace radius
if (distance > RADIUS && inRange) { //out of range
Log.i("Service", "out of range with notification");
inRange = false;
item.setExit(new Date());
db.createReport(item);
makeNotification();
isNotificationPosted = false;
}
}
}
lastKnownDistance = distance;
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onProviderDisabled(String provider) {
Toast.makeText( getApplicationContext(), "Please turn on your location services", Toast.LENGTH_SHORT ).show();
}
};
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(final Intent intent, int flags, int startId)
{
mLocationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);
final Address chosenAddress = intent.getParcelableExtra("chosen address");
chosenLocation = setLatLong(chosenAddress.getLongitude(), chosenAddress.getLatitude());
lastKnownDistance = INITIAL_DISTANCE;
Log.i("Service", "lase known location, distance: " + Float.toString(lastKnownDistance));
db = new DatabaseHelper(this);
ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
mLocationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
LOCATION_REFRESH_TIME,
LOCATION_REFRESH_DISTANCE,
mLocationListener
);
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
db.close();
ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
this.mLocationManager.removeUpdates(this.mLocationListener);
}
从 MainActivity 启动服务:
serviceIntent = new Intent(MainActivity.this, LocationService.class);
//selected address is from type Address
serviceIntent.putExtra("chosen address", selectedAddress);
saveIntentIntoSharedPreferences(serviceIntent);
startService(serviceIntent);
知道可能导致问题的原因吗?
谢谢!
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标签: java android service location main-activity