我有一个应用程序，我试图定期获取用户位置并发送到服务器。我有一个附加到 AlarmManager 的服务，它每分钟执行一次(用于测试)。该服务正确找到用户位置并注销 GPS 坐标。一旦有 GPS 锁定，我就会取消位置请求并停止服务。当我请求位置更新时，我启动了一个 Handler，它会在 20 秒后执行，这个 Handler 会删除位置更新并停止 Service 以防万一没有实现锁定。所有这些都有效。
下面是使用 Service 类的代码。
public class TrackingService extends Service {
private static final String TAG = TrackingService.class.getSimpleName();
LocationManager mlocManager;
LocationListener mlocListener;
NfcScannerApplication nfcscannerapplication;
String carerID;
Handler endServiceHandler;
Runnable endServiceRunnable;
@Override
public void onCreate() {
super.onCreate();
nfcscannerapplication = (NfcScannerApplication) getApplication();
mlocManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
Log.e(TAG, "Service created and location manager and listener created");
}
@Override
public void onDestroy() {
super.onDestroy();
Log.e(TAG, "in onDestroy in LocationService class");
mlocManager.removeUpdates(mlocListener);
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
Log.e(TAG, "requesting location updates");
enableMenuButtonsHandler();
endServiceHandler.postDelayed(endServiceRunnable,20 * 1000);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
Log.e(TAG, "in TrackingService onlocationChanged and about to send lon/lat " + loc.getLongitude() + " " + loc.getLatitude());
DateTime dt = new DateTime();
DateTimeFormatter df3 = DateTimeFormat.forPattern("yyyy-MM-dd H:mm:ss.SSS");
String formattedNowTime3 = df3.print(dt);
Log.e(TAG, "Time of location fix in TrackingServive = " + formattedNowTime3);
Cursor c = nfcscannerapplication.loginValidate.queryAllFromCarer();
if (c.getCount() > 0) {
if(c.moveToLast()){
carerID = c.getString(c.getColumnIndex(LoginValidate.C_CARER_ID));
}
}
Log.e(TAG, "carer ID = " + carerID);
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService)");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService");
}
@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
}
}// end of MyLocationListener
public void enableMenuButtonsHandler() {
endServiceHandler = new Handler();
endServiceRunnable = new Runnable() {
public void run() {
endService();
}
private void endService() {
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService) from the endService handler");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService from the endService handler");
}
};
}
}// end of service
我遇到的问题是，一旦我有了 GPS 锁定，我想将经纬度坐标发送到服务器。我知道我可以使用 Service 中的 AsyncTask，但我不想这样做。我更愿意使用 IntentService，因为它在自己的后台线程中运行。这样我就可以直接从 IntentService 进行网络调用。
以下代码实现了 IntentService 类，但它似乎没有获得锁。 GPS 会无限期地在手机上闪烁。日志记录语句最远是“请求位置更新”，之后什么也没有。
有没有人知道为什么没有实现锁定？提前致谢。
public class TrackingService extends IntentService {
private static final String TAG = TrackingService.class.getSimpleName();
LocationManager mlocManager;
LocationListener mlocListener;
NfcScannerApplication nfcscannerapplication;
String carerID;
Handler endServiceHandler;
Runnable endServiceRunnable;
public TrackingService() {
super("TrackingService");
}
@Override
protected void onHandleIntent(Intent intent) {
nfcscannerapplication = (NfcScannerApplication) getApplication();
mlocManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
Log.e(TAG, "Service created and location manager and listener created");
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
Log.e(TAG, "requesting location updates");
enableMenuButtonsHandler();
endServiceHandler.postDelayed(endServiceRunnable,20 * 1000);
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
Log.e(TAG, "in TrackingService onlocationChanged and about to send lon/lat " + loc.getLongitude() + " " + loc.getLatitude());
DateTime dt = new DateTime();
DateTimeFormatter df3 = DateTimeFormat.forPattern("yyyy-MM-dd H:mm:ss.SSS");
String formattedNowTime3 = df3.print(dt);
Log.e(TAG, "Time of location fix in TrackingServive = " + formattedNowTime3);
Cursor c = nfcscannerapplication.loginValidate.queryAllFromCarer();
if (c.getCount() > 0) {
if(c.moveToLast()){
carerID = c.getString(c.getColumnIndex(LoginValidate.C_CARER_ID));
}
}
Log.e(TAG, "carer ID = " + carerID);
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService)");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService");
}
@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
}
}// end of MyLocationListener
public void enableMenuButtonsHandler() {
endServiceHandler = new Handler();
endServiceRunnable = new Runnable() {
public void run() {
endService();
}
private void endService() {
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService) from the endService handler");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService from the endService handler");
}
};
}
}//end of trackingService
[编辑1]
public class TrackingService extends Service {
private static final String TAG = TrackingService.class.getSimpleName();
LocationManager mlocManager;
LocationListener mlocListener;
NfcScannerApplication nfcscannerapplication;
String carerID;
Handler endServiceHandler;
Runnable endServiceRunnable;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
nfcscannerapplication = (NfcScannerApplication) getApplication();
mlocManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
Log.e(TAG, "Service created and location manager and listener created");
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
Log.e(TAG, "requesting location updates");
enableMenuButtonsHandler();
endServiceHandler.postDelayed(endServiceRunnable, 20 * 1000);
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
super.onDestroy();
Log.e(TAG, "in onDestroy in LocationService class");
mlocManager.removeUpdates(mlocListener);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
Log.e(TAG, "in TrackingService onlocationChanged and about to send lon/lat " + loc.getLongitude() + " " + loc.getLatitude());
DateTime dt = new DateTime();
DateTimeFormatter df3 = DateTimeFormat.forPattern("yyyy-MM-dd H:mm:ss.SSS");
String formattedNowTime3 = df3.print(dt);
Log.e(TAG, "Time of location fix in TrackingServive = " + formattedNowTime3);
Cursor c = nfcscannerapplication.loginValidate.queryAllFromCarer();
if (c.getCount() > 0) {
if(c.moveToLast()){
carerID = c.getString(c.getColumnIndex(LoginValidate.C_CARER_ID));
}
}
Log.e(TAG, "carer ID = " + carerID);
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService)");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService");
}
@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
}
}// end of MyLocationListener
public void enableMenuButtonsHandler() {
endServiceHandler = new Handler();
endServiceRunnable = new Runnable() {
public void run() {
endService();
}
private void endService() {
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService) from the endService handler");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService from the endService handler");
}
};
}
}// end of service
[编辑2]
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
nfcscannerapplication = (NfcScannerApplication) getApplication();
mlocManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
Log.e(TAG, "Service created and location manager and listener created");
HandlerThread handlerThread = new HandlerThread("MyHandlerThread");
handlerThread.start();
Looper looper = handlerThread.getLooper();
Handler handler = new Handler(looper);
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener, looper);
Log.e(TAG, "requesting location updates");
enableMenuButtonsHandler();
endServiceHandler.postDelayed(endServiceRunnable, 20 * 1000);
return super.onStartCommand(intent, flags, startId);
}
[编辑3]
public class TrackingService extends Service {
private static final String TAG = TrackingService.class.getSimpleName();
LocationManager mlocManager;
LocationListener mlocListener;
NfcScannerApplication nfcscannerapplication;
String carerID;
Handler endServiceHandler;
Runnable endServiceRunnable;
HandlerThread handlerThread;
Looper looper;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
nfcscannerapplication = (NfcScannerApplication) getApplication();
mlocManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
Log.e(TAG, "Service created and location manager and listener created");
Log.e(TAG, "creating handlerthread and looper");
handlerThread = new HandlerThread("MyHandlerThread");
handlerThread.start();
looper = handlerThread.getLooper();
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener, looper);
Log.e(TAG, "requesting location updates");
enableMenuButtonsHandler();
endServiceHandler.postDelayed(endServiceRunnable, 20 * 1000);
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
super.onDestroy();
Log.e(TAG, "in onDestroy in LocationService class");
mlocManager.removeUpdates(mlocListener);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
Log.e(TAG, "in TrackingService onlocationChanged and about to send lon/lat " + loc.getLongitude() + " " + loc.getLatitude());
DateTime dt = new DateTime();
DateTimeFormatter df3 = DateTimeFormat.forPattern("yyyy-MM-dd H:mm:ss.SSS");
String formattedNowTime3 = df3.print(dt);
Log.e(TAG, "Time of location fix in TrackingServive = " + formattedNowTime3);
Cursor c = nfcscannerapplication.loginValidate.queryAllFromCarer();
if (c.getCount() > 0) {
if(c.moveToLast()){
carerID = c.getString(c.getColumnIndex(LoginValidate.C_CARER_ID));
}
}
Log.e(TAG, "carer ID = " + carerID);
nfcscannerapplication.loginWebservice.sendCarerLocation(carerID, formattedNowTime3, String.valueOf(loc.getLatitude()), String.valueOf(loc.getLongitude()));
Log.e(TAG, "quiting handlerthread");
handlerThread.quit();
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService)");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService");
}
@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
}
}// end of MyLocationListener
public void enableMenuButtonsHandler() {
endServiceHandler = new Handler();
endServiceRunnable = new Runnable() {
public void run() {
endService();
}
private void endService() {
mlocManager.removeUpdates(mlocListener);
Log.e(TAG, "removed updates(TrackingService) from the endService handler");
TrackingService.this.stopSelf();
Log.e(TAG, "called stopSelf on TrackingService from the endService handler");
Log.e(TAG, "quiting handlerthread from the endService handler");
handlerThread.quit();
}
};
}
}// end of service
最佳答案
正如 Pankaj Kumar 指出的那样，IntentService 对于要完成的工作本质上是异步的情况来说不是合适的解决方案。一旦 onHandleIntent() 返回，您的服务就会被销毁。
使用常规 Service，在 onStartCommand() 中注册位置，使用 HandlerThread 处理结果(这样您就可以通过它Looper 进入 requestLocationUpdates())。收到您的位置信息或达到合适的超时时间后，执行您的工作并调用服务上的 stopSelf() 将其关闭。
关于android - 位置监听器从服务工作，但不是 IntentService，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19978939/