地理围栏:通过后台服务发送时,HTTP请求失败.给出UnknownHostException

Question

我在android应用程序中实现了Geofence.我按照这个链接在app中实现了'Geofence'.我正在使用'Retrofit'库来调用'HTTP'请求.

应用具有以下权限:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

这是我的'IntentService'代码:

public class GeofenceService extends IntentService
{

    private static  final String TAG = GeofenceService.class.getName();


    public static final int GEOFENCE_NOTIFICATION_ID = 0;


    public GeofenceService() {
        super(TAG);
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        // Retrieve the Geofencing intent
        GeofencingEvent geofencingEvent = GeofencingEvent.fromIntent(intent);


        createLoggerFile();
        // Handling errors
        if ( geofencingEvent.hasError() ) {
            String errorMsg = getErrorString(geofencingEvent.getErrorCode() );
            Logger.Important(true,  TAG, "onHandleIntent() :: errorMessage : "+errorMsg );
            return;
        }

        // Retrieve GeofenceTrasition
        int geoFenceTransition = geofencingEvent.getGeofenceTransition();
        // Check if the transition type
        if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER ||
                geoFenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT ||
                geoFenceTransition == Geofence.GEOFENCE_TRANSITION_DWELL)
        {
            Log.d(TAG, "onHandleIntent() :: geoFenceTransition : " + geoFenceTransition);
            // Get the geofence that were triggered
            List<Geofence> triggeringGeofences = geofencingEvent.getTriggeringGeofences();
            // Create a detail message with Geofences received
            String geofenceTransitionDetails = getGeofenceTrasitionDetails(geoFenceTransition, triggeringGeofences );
            // Send notification details as a String
            sendNotification( geofenceTransitionDetails );

        }
    }

    // Create a detail message with Geofences received
    private String getGeofenceTrasitionDetails(int geoFenceTransition, List<Geofence> triggeringGeofences) {
        // get the ID of each geofence triggered
        ArrayList<String> triggeringGeofencesList = new ArrayList<>();
        for ( Geofence geofence : triggeringGeofences ) {
            triggeringGeofencesList.add( geofence.getRequestId() );
        pingGoogle();  // here is I am pinging google

        callingHttpRequest(); // calling Http request. Also I called this request through application class, but still it is not worked in background.


        }


        String status = null;
        if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER )
            status = "Entering ";
        else if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT )
            status = "Exiting ";
        else if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_DWELL )
            status = "Staying ";
        return status + TextUtils.join( ", ", triggeringGeofencesList);
    }

    // Send a notification
    private void sendNotification( String msg ) {
        Log.d( TAG, "sendNotification: " + msg );

        // Intent to start the main Activity
        Intent notificationIntent = new Intent(getApplicationContext(), DrawerActivity.class);;

        TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
        stackBuilder.addParentStack(DrawerActivity.class);
        stackBuilder.addNextIntent(notificationIntent);
        PendingIntent notificationPendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

        // Creating and sending Notification
        NotificationManager notificatioMng =
                (NotificationManager) getSystemService( Context.NOTIFICATION_SERVICE );
        notificatioMng.notify(
                GEOFENCE_NOTIFICATION_ID,
                createNotification(msg, notificationPendingIntent));
    }

    // Create a notification
    private Notification createNotification(String msg, PendingIntent notificationPendingIntent) {
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this);
        notificationBuilder
                .setSmallIcon(R.drawable.ic_phi_notification_logo)
                .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.geo))
                .setColor(Converter.getColor(getApplicationContext(), R.color.default_pure_cyan))
                .setContentTitle(JsonKey.TRIGGER)
                .setContentText(msg)
                .setContentIntent(notificationPendingIntent)
                .setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_VIBRATE | Notification.DEFAULT_SOUND)
                .setAutoCancel(true);
        return notificationBuilder.build();
    }

    // Handle errors
    private static String getErrorString(int errorCode) {
        switch (errorCode) {
            case GeofenceStatusCodes.GEOFENCE_NOT_AVAILABLE:
                return "GeoFence not available";
            case GeofenceStatusCodes.GEOFENCE_TOO_MANY_GEOFENCES:
                return "Too many GeoFences";
            case GeofenceStatusCodes.GEOFENCE_TOO_MANY_PENDING_INTENTS:
                return "Too many pending intents";
            default:
                return "Unknown error.";
        }
    }



 private void callingHttpRequest() {

     HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

        OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .readTimeout(10, TimeUnit.SECONDS)
                .connectTimeout(10 / 2, TimeUnit.SECONDS)
                .sslSocketFactory(sslSocketFactory().getSocketFactory())
                .build();

    Gson gson = new GsonBuilder()
                .setLenient()
                .create();

             Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(url)
                .client(client)
                .addConverterFactory(GsonConverterFactory.create(gson))
                .build();


            API api = retrofit.create(***.class);


            Call<ResponseBody> req = api.callGeofencingTrigger(***);

            req.enqueue(new Callback<ResponseBody>() {

                @Override
                public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> response) {
                    try {
                        String string = response.body().string();
                        Log.d (TAG, "onResponse()  :: success");

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }

                @Override
                public void onFailure(Call<ResponseBody> call, Throwable t) {
                    t.printStackTrace();
                   Log.d (TAG, "onFailure()  :: t : "t.getMessage());

                }

            });

    }
}

每当设备获得地理围栏触发器时,它工作正常并在应用程序处于后台或前台(进入/停留/离开)或即使用户从最近的任务中杀死应用程序时提供适当的触发通知.当我调用HTTP请求时,当应用程序在前台时,它工作正常,它在日志上打印成功.

onResponse()  :: success

但是当应用程序从最近的任务中被杀死并且设备获得任何地理围栏触发器(输入/停留/离开)时,HTTP请求将无法正确执行.它给 :

onFailure() :: t : 
</br>java.net.UnknownHostException: Unable to resolve host
"host_name": No address associated with hostname

其中host_name是服务器地址.

我从后台服务ping 谷歌或8.8.8.8 ip.仍面临同样的问题.当应用程序处于前台时,这个东西也可以正常运行但是在杀死应用程序后它不起作用.

那么,为什么这个错误呢？当应用程序不在最近的任务中时,网络通信是否未调用？

<------------------------------------------------- -------------------------------------------------- ----------------------->
我试过以下的事情.从@Xavier和@Stevensen获得答案后

我在我的应用程序中使用firebase-jobscheduler来调用HTTP请求.这是我的代码:

在我的清单中,我添加了以下服务:

 <service
            android:exported="false"
            android:name="com.****.service.TriggerJobService">
            <intent-filter>
                <action android:name="com.firebase.jobdispatcher.ACTION_EXECUTE"/>
            </intent-filter>
        </service>

这是我修改过的GeofenceService类.我刚刚callingHttpRequest()通过调用scheduleJob()函数getGeofenceTrasitionDetails()函数删除并添加了调度作业.代码和它一样.

public class GeofenceService extends IntentService
    {

        private static  final String TAG = GeofenceService.class.getName();


        public static final int GEOFENCE_NOTIFICATION_ID = 0;


        public GeofenceService() {
            super(TAG);
        }

        @Override
        protected void onHandleIntent(Intent intent) {
            // Retrieve the Geofencing intent
            GeofencingEvent geofencingEvent = GeofencingEvent.fromIntent(intent);


            createLoggerFile();
            // Handling errors
            if ( geofencingEvent.hasError() ) {
                String errorMsg = getErrorString(geofencingEvent.getErrorCode() );
                Logger.Important(true,  TAG, "onHandleIntent() :: errorMessage : "+errorMsg );
                return;
            }

            // Retrieve GeofenceTrasition
            int geoFenceTransition = geofencingEvent.getGeofenceTransition();
            // Check if the transition type
            if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER ||
                    geoFenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT ||
                    geoFenceTransition == Geofence.GEOFENCE_TRANSITION_DWELL)
            {
                Log.d(TAG, "onHandleIntent() :: geoFenceTransition : " + geoFenceTransition);
                // Get the geofence that were triggered
                List<Geofence> triggeringGeofences = geofencingEvent.getTriggeringGeofences();
                // Create a detail message with Geofences received
                String geofenceTransitionDetails = getGeofenceTrasitionDetails(geoFenceTransition, triggeringGeofences );
                // Send notification details as a String
                sendNotification( geofenceTransitionDetails );

            }
        }

        // Create a detail message with Geofences received
        private String getGeofenceTrasitionDetails(int geoFenceTransition, List<Geofence> triggeringGeofences) {
            // get the ID of each geofence triggered
            ArrayList<String> triggeringGeofencesList = new ArrayList<>();
            for ( Geofence geofence : triggeringGeofences ) {
                triggeringGeofencesList.add( geofence.getRequestId() );

            scheduleJob(); // <code>**Here I schedule job**</code>


            }


            String status = null;
            if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_ENTER )
                status = "Entering ";
            else if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_EXIT )
                status = "Exiting ";
            else if ( geoFenceTransition == Geofence.GEOFENCE_TRANSITION_DWELL )
                status = "Staying ";
            return status + TextUtils.join( ", ", triggeringGeofencesList);
        }

        // Send a notification
        private void sendNotification( String msg ) {
            Log.d( TAG, "sendNotification: " + msg );

            // Intent to start the main Activity
            Intent notificationIntent = new Intent(getApplicationContext(), DrawerActivity.class);;

            TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
            stackBuilder.addParentStack(DrawerActivity.class);
            stackBuilder.addNextIntent(notificationIntent);
            PendingIntent notificationPendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

            // Creating and sending Notification
            NotificationManager notificatioMng =
                    (NotificationManager) getSystemService( Context.NOTIFICATION_SERVICE );
            notificatioMng.notify(
                    GEOFENCE_NOTIFICATION_ID,
                    createNotification(msg, notificationPendingIntent));
        }

        // Create a notification
        private Notification createNotification(String msg, PendingIntent notificationPendingIntent) {
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this);
            notificationBuilder
                    .setSmallIcon(R.drawable.ic_phi_notification_logo)
                    .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.geo))
                    .setColor(Converter.getColor(getApplicationContext(), R.color.default_pure_cyan))
                    .setContentTitle(JsonKey.TRIGGER)
                    .setContentText(msg)
                    .setContentIntent(notificationPendingIntent)
                    .setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_VIBRATE | Notification.DEFAULT_SOUND)
                    .setAutoCancel(true);
            return notificationBuilder.build();
        }

        // Handle errors
        private static String getErrorString(int errorCode) {
            switch (errorCode) {
                case GeofenceStatusCodes.GEOFENCE_NOT_AVAILABLE:
                    return "GeoFence not available";
                case GeofenceStatusCodes.GEOFENCE_TOO_MANY_GEOFENCES:
                    return "Too many GeoFences";
                case GeofenceStatusCodes.GEOFENCE_TOO_MANY_PENDING_INTENTS:
                    return "Too many pending intents";
                default:
                    return "Unknown error.";
            }
        }

 private void scheduleJob()
    {


        Bundle bundle = new Bundle();


        FirebaseJobDispatcher dispatcher = new FirebaseJobDispatcher(new GooglePlayDriver(getApplicationContext()));
        Job.Builder builder = dispatcher.newJobBuilder();

        builder.setExtras(bundle);
        builder.setTag(requestId);
        builder.setService(TriggerJobService.class);
        builder.setTrigger(Trigger.executionWindow(10, 30));
        builder.setReplaceCurrent(true);
        builder.addConstraint(Constraint.DEVICE_CHARGING);
        builder.addConstraint(Constraint.ON_ANY_NETWORK);
        builder.addConstraint(Constraint.ON_UNMETERED_NETWORK);

        dispatcher.mustSchedule(builder.build());

    }

}

这是我的TriggerJobService代码:

public class TriggerJobService extends JobService
{
    private static final String TAG = TriggerJobService.class.getName();

    private int count;
    @Override
    public boolean onStartJob(JobParameters job)
    {
        Log.d(TAG, "onStartJob() :: " + job.getTag());
        // Return true as there's more work to be done with this job.
        //TODO have to send request to cloud
        Bundle bundle = job.getExtras();
         callingHttpRequest();   // here is I am calling 'HTTP' request

        return true;
    }

    @Override
    public boolean onStopJob(JobParameters job)
    {
        Log.d(TAG, "onStopJob() :: " + job.getTag());
        // Return false to drop the job.
        return false;
    }

 private void callingHttpRequest() {

         HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
            interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

            OkHttpClient client = new OkHttpClient.Builder()
                    .addInterceptor(interceptor)
                    .readTimeout(10, TimeUnit.SECONDS)
                    .connectTimeout(10 / 2, TimeUnit.SECONDS)
                    .sslSocketFactory(sslSocketFactory().getSocketFactory())
                    .build();

        Gson gson = new GsonBuilder()
                    .setLenient()
                    .create();

                 Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl(url)
                    .client(client)
                    .addConverterFactory(GsonConverterFactory.create(gson))
                    .build();


                API api = retrofit.create(***.class);


                Call<ResponseBody> req = api.callGeofencingTrigger(***);

                req.enqueue(new Callback<ResponseBody>() {

                    @Override
                    public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> response) {
                        try {
                            String string = response.body().string();
                            Log.d (TAG, "onResponse()  :: success");

                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }

                    @Override
                    public void onFailure(Call<ResponseBody> call, Throwable t) {
                        t.printStackTrace();
                       Log.d (TAG, "onFailure()  :: t : "t.getMessage());

                    }

                });

        }
}

它再次呼吁相同.当app处于后台或前台(进入/停留/离开)或即使用户从最近的任务中杀死应用程序时,它工作正常并提供适当的触发通知.它也正在安排适当的工作.并且调用HTTP请求,当应用程序在前台时,它工作正常,并在日志上打印成功.

onResponse()  :: success

但是当应用程序从最近的任务中被杀死并且设备获得任何地理围栏触发器(进入/停留/离开)时,应用程序调度作业并且调用HTTP请求未正确执行.它给 :

onFailure() :: t : 
</br>java.net.UnknownHostException: Unable to resolve host
"host_name": No address associated with hostname

因此,根据@Xavier和@Stevensen的回答,我的应用程序不会唤醒网络,如果它从最近的任务中杀死.我试过firbase-JobSchedule但仍面临同样的错误.当app从最近的任务中杀死时,应用程序是否需要任何特殊permission的呼叫HTTP请求？或者是FCM更好的选择.但是,FCM即使应用程序从最近的任务中杀死,仍然会有同样的问题是否有效吗？也FCM将唤醒网络从客户端发送消息到服务器？

Answer 1

也许你的应用程序被Androids打盹模式和/或应用程序待机状态阻止使用网络.检查Doze和App Standby的优化.

可能的解决方案是使用AlarmManager设置警报.Android将在允许您使用网络的维护窗口中安排警报处理.

Answer 2

@Stevensen 关于 Doze 模式是失败原因的解释更有可能是原因。在文档中您可以阅读：

处于打瞌睡状态时，以下限制适用于您的应用程序： 网络访问被暂停...

我建议将事件存储在数据库中，并使用JobScheduler（API 21+，请参阅此处的教程）安排作业将它们上传到服务器，或者，如果您需要支持较旧的设备，请使用此替换firebase -jobdispatcher（通过包装 GCM Network Manager 提供与 JobScheduler 兼容的 API）。

我建议设置一个需要的网络条件：.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)并且可能.setPeriodic(long intervalMillis)限制它发生的次数（例如，每小时最多上传一次）。

只要不需要实时性，这是一种节省电池的更好的用户体验方法：打瞌睡模式将帮助设备节省电池寿命，并且JobScheduler允许批量上传并时不时唤醒无线电，从而节省电池生活。请观看这段简短视频以了解其基本原理。