如何隐藏应用程序时发送和接收数据？
问题描述：
当应用程序被隐藏或屏幕关闭时，我的应用程序不会向PHP脚本发送JSON字符串。我使用HttpURLConnection。我的应用程序发送一个GPS位置。我想，该应用程序像messanger一样在backgoround中工作。发送和接收数据发生在AsyncTask中。哪里不对？如何隐藏应用程序时发送和接收数据？
public class MyAsyncTask extends AsyncTask<JSONObject, Void, JSONObject> {
String addr = GlobalConfig.addr;
String prot = GlobalConfig.prot;
int port = GlobalConfig.port;
@Override
protected void onPreExecute() {
}
@Override
protected JSONObject doInBackground(JSONObject... params) {
JSONObject json = params[0];
String string = "json="+json;
try {
URL url = new URL(prot,addr,port,"json/myLocation.php");
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setDoOutput(true);
httpCon.setDoInput(true);
httpCon.setUseCaches(false);
httpCon.setConnectTimeout(15000);
httpCon.setRequestProperty("Content-Length", Integer.toString(string.length()));
httpCon.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
httpCon.setRequestMethod("POST");
DataOutputStream wr = new DataOutputStream(httpCon.getOutputStream());
wr.writeBytes(string);
wr.flush();
wr.close();
int responseCode = httpCon.getResponseCode();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(JSONObject json) {
}
}
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
private static final long MIN_TIME_BW_UPDATES = 10000;
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
return latitude;
}
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
return longitude;
}
public boolean canGetLocation() {
return this.canGetLocation;
}
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
alertDialog.setTitle("GPS is settings");
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
int ID = GlobalConfig.ID;
int Random = GlobalConfig.Random;
double latitude = location.getLatitude();
double longitude = location.getLongitude();
try {
JSONObject json = new JSONObject();
json.put("ID", ID);
json.put("Random", Random);
json.put("latitude", latitude);
json.put("longitude", longitude);
new MyAsyncTask().execute(json);
} catch(Exception e){
e.printStackTrace();
}
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
是这样的吗？
答
我认为你是混合不同的事情：
的AsyncTask意味着代码在一个单独的任务（线程）运行，但仍然在你的活动环境。这意味着它运行在你的应用程序的后台，并不会停止你的应用程序的执行。
服务能够在没有任何活动上下文的情况下在后台执行代码。这就像系统的背景一样。
为了实现你想要的，你必须把你的任务放在一个服务中。
答
您需要结合使用这些工作。
首先，您需要查看使您的服务变得粘滞。要做到这一点，按照下列步骤进行：
Android Service needs to run always (Never pause or stop)
粘滞服务是运行，直到你明确告诉它关闭（http://developer.android.com/reference/android/app/Service.html#START_STICKY）
您也想看看wakefulBroadcastReceiver服务为每该文档：https://developer.android.com/reference/android/support/v4/content/WakefulBroadcastReceiver.html
这样，当设备重新启动或在关机后启动后，它会再次启动您的服务。
为了更加安全，您还需要看看这里通过实施这一方案实施某种形式的network broadcast receiver，例如：Broadcast receiver for checking internet connection in android app
这最后一个是这样，你不尝试发送的东西当没有网络连接时，而是在设备重新联机时启动服务。
但是，我确实建议您对此谨慎行事。你一直在运行，总是上传服务将消耗大量的权力，也许你想限制它发送的数据量和它收集这些数据的时间间隔，但这取决于你听或不:)。
请发布您的代码并清除您的问题更多 – therealprashant