Intent Service 如何在后台连续运行？

Question

所以我正在使用 Activity Recognition API，我为它创建了一个名为 ActivityRecognitionIntentService 的服务。

我真的希望它一直在后台工作。

问题是应用程序显示在缓存的运行服务中，但在我退出应用程序时关闭并且不在后台运行。

我正在为我的主要活动使用广播接收器来更新 UI。

我正在使用IntentService，我创建了onStartCommand，它返回START_STICKY。

import android.app.IntentService;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.ActivityRecognition;
import com.google.android.gms.location.ActivityRecognitionResult;
import com.google.android.gms.location.DetectedActivity;

public class ActivityRecognitionIntentService extends IntentService implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {

    Context mContext;
    GoogleApiClient mGApiClient;
    BroadcastReceiver receiver;
    private static final String TAG = ActivityRecognitionIntentService.class.getSimpleName();

    public ActivityRecognitionIntentService() {
        super("ActivityRecognitionIntentService");

    }

    @Override
    protected void onHandleIntent(Intent intent) {
        if(ActivityRecognitionResult.hasResult(intent)) {
            //Extract the result from the Response
            ActivityRecognitionResult result = ActivityRecognitionResult.extractResult(intent);
            DetectedActivity detectedActivity = result.getMostProbableActivity();

            //Get the Confidence and Name of Activity
            int confidence = detectedActivity.getConfidence();
            String mostProbableName = getActivityName(detectedActivity.getType());

            //Fire the intent with activity name & confidence
            Intent i = new Intent("ImActive");
            i.putExtra("activity", mostProbableName);
            i.putExtra("confidence", confidence);

            Log.d(TAG, "Most Probable Name : " + mostProbableName);
            Log.d(TAG, "Confidence : " + confidence);

            //Send Broadcast to be listen in MainActivity
            this.sendBroadcast(i);

        }else {
            Log.d(TAG, "Intent had no data returned");
        }
    }

    //Get the activity name
    private String getActivityName(int type) {
        switch (type)
        {
            case DetectedActivity.IN_VEHICLE:
                return "still";
            case DetectedActivity.ON_BICYCLE:
                return "moving";
            case DetectedActivity.ON_FOOT:
                return "moving";
            case DetectedActivity.WALKING:
                return "moving";
            case DetectedActivity.STILL:
                return "still";
            case DetectedActivity.TILTING:
                return "still";
            case DetectedActivity.UNKNOWN:
                return "still";
            case DetectedActivity.RUNNING:
                return "moving";

        }
        return "N/A";
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        super.onStartCommand(intent,flags,startId);
        buildGoogleClient();
        Toast.makeText(this, "service starting", Toast.LENGTH_SHORT).show();
        return START_STICKY;
    }

    private boolean isPlayServiceAvailable() {
        return GooglePlayServicesUtil.isGooglePlayServicesAvailable(mContext) == ConnectionResult.SUCCESS;
    }

    private void buildGoogleClient()
    {
        //Check Google Play Service Available
        if (isPlayServiceAvailable()) {
            mGApiClient = new GoogleApiClient.Builder(this)
                    .addApi(ActivityRecognition.API)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .build();
            //Connect to Google API
            mGApiClient.connect();
        }
    }

    @Override
    public void onConnected(Bundle bundle) {
        Intent i = new Intent(this, ActivityRecognitionIntentService.class);
        PendingIntent mActivityRecongPendingIntent = PendingIntent
                .getService(this, 0, i, PendingIntent.FLAG_UPDATE_CURRENT);

        Log.d(TAG, "connected to ActivityRecognition");
        ActivityRecognition.ActivityRecognitionApi.requestActivityUpdates(mGApiClient, 0, mActivityRecongPendingIntent);

    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.d(TAG, "Suspended to ActivityRecognition");
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.d(TAG, "Not connected to ActivityRecognition");
    }

}

我也在清单中声明了服务

 <service android:name=".ActivityRecognitionIntentService"
        android:exported="false"/>

以及必要的权限

<uses-permission android:name="com.google.android.gms.permission.ACTIVITY_RECOGNITION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

Answer 1

您需要扩展 Service 而不是 IntentService，并且您必须显示 Ongoing Notification 以便操作系统不会终止您的服务

这是一个例子：

public class RunnerService extends Service {

    private Notification mNotification;
    private static int notificationId = 1;


    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        // get abitmap to be displayed in the notification
        Bitmap bmp = BitmapFactory.decodeResource(Res.getResources(),
                getApplicationInfo().icon);

        // make a notification Object, some of my code in parameters 
        mNotification = new NotificationCompat.Builder(this)
                .setTicker(Res.string(R.string.notification_ticker))
                .setContentTitle(Res.string(R.string.notification_title))
                .setContentText(Res.string(R.string.notification_txt_small))
                .setSmallIcon(R.drawable.dummyicon)
                .setLargeIcon(bmp)
                .setAutoCancel(true)
                .setPriority(Notification.PRIORITY_LOW)
                .setContentIntent(
                        PendingIntent.getActivity(this, 0, i,
                                PendingIntent.FLAG_UPDATE_CURRENT))
                .setStyle(
                        new NotificationCompat.BigTextStyle().bigText(Res
                                .string(R.string.notification_txt_big)))
                .setWhen(System.currentTimeMillis()).build();

        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN) {
            mNotification.priority = Notification.PRIORITY_MIN;
        }


    } 

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        // this should do the trick
        startForeground(notificationId, mNotification);

        // should return START_STICKY
        return START_STICKY;

    } 

    // stop your service from being in the foreground, call this 
    // before stopping the service
    public void stopForeground() {
        notificationId++;
        stopForeground(true);
    }

}