关闭应用程序后，保持定位服务正常运行 [英] Keep location service alive when the app is closed
问题描述
我有一项服务，当用户更改其位置时会发送通知.该服务运行良好，但是当用户也关闭该应用程序时会出现问题.
I have a service which sends a notification when the user changes his/her location. This service is working fine, but the problem arises when the user closes the app as the service closes too.
即使关闭了应用程序，我如何仍可以使该服务仍然有效?
我的服务是:
public class LocationService extends Service implements LocationListener {
public final static int MINUTE = 1000 * 60;
boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location; // location
double latitude = 0; // latitude
double longitude = 0; // longitude
String provider;
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1 * MINUTE;
// Declaring a Location Manager
protected LocationManager locationManager;
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
public LocationService getService() {
// Return this instance of LocalService so clients can call public
// methods
return LocationService.this;
}
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public Location getLocation() {
try {
locationManager = (LocationManager) getBaseContext().getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled. DEFAULT COORDINATES
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES,
this);
Log.d("Network", "Network Enabled");
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES,
this);
Log.d("GPS", "GPS Enabled");
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
Log.i("LOCATION", "Latitude: " + latitude + "- Longitude: " + longitude);
return location;
}
@Override
public void onLocationChanged(Location arg0) {
NotificationManager mNotificationManager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
Intent intent = null;
intent = new Intent(this, CompleteSurveyActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this).setSmallIcon(R.drawable.ic_launcher).setAutoCancel(true)
.setContentIntent(contentIntent).setContentTitle(this.getString(R.string.app_name)).setContentText("text");
// mBuilder.setContentIntent(contentIntent);
mNotificationManager.notify((int) System.currentTimeMillis() % Integer.MAX_VALUE, mBuilder.build());
double longitude = location.getLongitude();
double latitude = location.getLatitude();
Log.i("LOCATION", "Latitude: " + latitude + "- Longitude: " + longitude);
}
@Override
public void onProviderDisabled(String arg0) {
}
@Override
public void onProviderEnabled(String arg0) {
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
}
}
我从这里打来的电话:
public class MyActivity extends Activity {
LocationService mService;
boolean mBound = false;
private ServiceConnection mConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName className, IBinder service) {
// We've bound to LocalService, cast the IBinder and get
// LocalService instance
LocalBinder binder = (LocalBinder) service;
mService = binder.getService();
mBound = true;
}
@Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
exampleButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
initService();
}
});
}
public void initService() {
if (mBound)
mService.getLocation();
}
@Override
protected void onStart() {
super.onStart();
// Bind to LocalService
Intent intent = new Intent(this, LocationService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStop() {
super.onStop();
// Unbind from the service
if (mBound) {
unbindService(mConnection);
mBound = false;
}
}
}
Manifest.xml
<service android:name=".LocationService" android:enabled="true"></service>
推荐答案
与@ sven-menschner所说的相反，我认为未绑定的Service正是您所需要的，因为绑定的服务受绑定/取消绑定机制的约束，会杀死您的服务.那就是我要做的:
Oppositely to what @sven-menschner said, I think an unbound Service is exactly what you need, as bound services are subject to bind/unbind mechanisms that would kill your service. That's what I would do:
在清单文件中，定义您的服务:
In your Manifest file, define your service:
<service
android:name=".YourService"
android:enabled="true"
android:exported="true"
android:description="@string/my_service_desc"
android:label="@string/my_infinite_service">
<intent-filter>
<action android:name="com.yourproject.name.LONGRUNSERVICE" />
</intent-filter>
</service>
注意:这里有一个已实施操作的列表，但是您可以定义自己的操作来启动该服务.只需创建一个单例类并定义字符串，为它们分配一个唯一的String即可.设置为true的"enabled"仅用于实例化服务，而设置为true的导出设置仅在您需要其他将意图发送到Service的应用程序的情况下使用.如果没有，则可以安全地将最后一个设置为false.
Note: There's a list of already implemented actions, but you can define your own actions for the intent to launch the service. Simply create a singleton class and define the strings assigning them a String that should be unique. The "enabled" set to true is just to instantiate the service, and exported set to true is just in the case you need other applications sending intents to your Service. If not, you can safely set that last to false.
接下来的步骤是从您的活动开始服务.可以很容易地通过以下方式完成:
The following step would be starting your service from your activity. That can be easily done by:
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent servIntent = new Intent("com.yourproject.name.LONGRUNSERVICE");
startService(servIntent);
...
}
}
最后一步是定义您的Service初始化.留意onBind()方法.由于您不希望绑定它，因此只需返回null.会是这样的:
The final step is to define your Service initializations. Keep an eye on the onBind() method. Since you don't want it to be bound, simply return null. It would be something like this:
public class MyService extends Service {
@Override
public IBinder onBind(Intent intent) {
// This won't be a bound service, so simply return null
return null;
}
@Override
public void onCreate() {
// This will be called when your Service is created for the first time
// Just do any operations you need in this method.
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}
}
现在，即使关闭主Activity，您的服务也将运行.仅剩一步:为了帮助您完成Service，请将其作为前台服务运行(在您的Service中执行).这基本上将在状态栏中创建一个通知图标.这并不意味着您的主要Activity也正在运行(这就是为什么您不想要绑定服务的原因)，因为Activity和Services具有不同的生命周期.为了帮助该Service运行很长时间，请尝试将您的堆保持在尽可能低的水平，以免Android SO杀死它.
Now your service will run even if you close your main Activity. There's just one step left: To help your Service not being finished, run it as a foreground service (do that within your Service). This will basically create a notification icon in the status bar. This doesn't mean your main Activity is running too (this is why you don't want a bound service), as Activities and Services have different life-cycles. In order to help that Service run for so long, try keeping your heap as low as possible so it will avoid the Android SO killing it.
另一个声明:您无法测试服务是否仍在运行以杀死DVM.如果杀死DVM，则将杀死所有内容，因此也将杀死服务.
One more acclaration: You cannot test whether the Service is still running killing the DVM. If you kill the DVM, you'll killing everything, thus also the Service.
这篇关于关闭应用程序后，保持定位服务正常运行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
