java - 如何在设定的超时时间内运行异步任务？

Question

我想运行我的异步任务，它以一定的精度获取坐标，并在获取坐标时启动不同的 Activity 。

现在我想设置一个时间，这样如果它没有获得具有设定精度的坐标，那么异步任务应该自行销毁(删除位置更新等)并传递纬度/经度的默认值.

我试过使用这个:new GetGPShotfix().execute().get(1, TimeUnit.MINUTES); 以便为此异步设置超时一分钟，然后继续执行此异步执行下的下一行/任务打电话。

但在我的例子中，它会跳到下一行，而不会等待 Async 设置的超时。

如何让它按照我想要的方式执行？我也尝试使用线程的 join() 但显然结果是一样的:(

更新:这是我的代码(用于 gpshotfix() Async):

private class GetGPShotfix extends AsyncTask<Void, Void, Void> {
    // ProgressDialog progressDialogGPS;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        Log.i("GPSfixer", "Ready to get GPS Hotfix");



    }

    @Override
    protected Void doInBackground(Void... params) {

        try {
            LocationRetriever myLoc = new LocationRetriever();
            // myLoc.getUserLoc();
            //if (gotLoc == 0  && (firstLoc.getAccuracy() > 10)) {
            if (gotLoc == 0) {
                myLoc.getUserLoc();
            }


        } catch (Exception e) {
            Log.i("GPSfixer", "GPS Hotfix Failed!", e);

        }

        finally {

            Log.i("GPSfixer", "Get GPS Hotfix Completed...");

        }
        return null;
    }

    @Override
    protected void onCancelled() {
        Log.i("GPSfixer", "Get GPS Hotfix Cancelled");
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        Log.i("GPSfixer", "GPS Hotfix cycle completed");
        System.out.println("Lon :" + myCurrentLon + "Lon2: " + finalLonNow);
        System.out.println("Lat :" + myCurrentLat + "Lat2: " + finalLatNow);
        //pDialog2.dismiss();
        // progressDialogGPS.dismiss();

    }
}

public class LocationRetriever {
    final LocationManager locationManager = (LocationManager) StoreSelection.this.getSystemService(Context.LOCATION_SERVICE);

    final LocationListener locationListener = new LocationListener() {

        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub
            Toast.makeText(getApplicationContext(),
                    provider + " is disabled!", Toast.LENGTH_SHORT).show();
            Toast.makeText(getApplicationContext(),
                    "Please standby..enabling " + provider,
                    Toast.LENGTH_SHORT).show();

            // explicitly enable GPS
            Intent enableGPS = new Intent("android.location.GPS_ENABLED_CHANGE");
            enableGPS.putExtra("enabled", true);
            sendBroadcast(enableGPS);

            // explictly disable GPS
            /*
             * Intent intent = new
             * Intent("android.location.GPS_ENABLED_CHANGE");
             * intent.putExtra("enabled", false); sendBroadcast(intent);
             */

        }

        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub
            Toast.makeText(getApplicationContext(),
                    provider + " is enabled..", Toast.LENGTH_SHORT).show();

        }

        public void onStatusChanged(String provider, int status,
                Bundle extras) {
            // TODO Auto-generated method stub
            /*
             * System.out.println("val of status: " + status + " provider: "
             * + provider);
             */
            if (status == 1) {
                Toast.makeText(getApplicationContext(),
                        provider + " is enabled & available..",
                        Toast.LENGTH_SHORT).show();

                System.out.println(provider + " is NOT available!");
            } else {
                System.out.println(provider + " is NOT available!");
            }

            /* progressDialogGPS.dismiss(); */

        }

        public void onLocationChanged(Location location) {
            // TODO Auto-generated method stub

            // ORIG CODE --BELOW--

            // moved lat/lon vars to top ^


            myCurrentLon = location.getLongitude();
            myCurrentLat = location.getLatitude();

            firstLoc = location;

            myCurrentLon = Double.parseDouble(new DecimalFormat("##.#########")
                    .format(myCurrentLon));
            myCurrentLat = Double.parseDouble(new DecimalFormat("##.#########")
                    .format(myCurrentLat));

            /*Toast.makeText(getApplicationContext(),
                    myCurrentLat + " " + myCurrentLon, Toast.LENGTH_SHORT)
                    .show();*/
            System.out.println(myCurrentLat + " " + myCurrentLon);

            float acc=location.getAccuracy();
            /*Toast.makeText(getApplicationContext(), "Acc.: " + acc,Toast.LENGTH_SHORT).show();*/

            // --

            // get best out of 2 locs. --BEGINS--
            /*
             * makeUseOfNewLocation(location);
             * 
             * if(currentBestLocation == null){ currentBestLocation =
             * location; }
             */
            if (myCurrentLon != null && myCurrentLat != null && (firstLoc.getAccuracy() <= 10)) { // added
                                                                                // chk
                                                                                // for
                                                                                // online..
                gotLoc = 1;
                System.out.println("OK GOTLOC == 1 !");
                System.out.println("Got your Current Location..disabling GPS to save Battery Power..");
                Toast.makeText(getApplicationContext(), "Got your Current Location..disabling GPS to save Battery Power..", Toast.LENGTH_SHORT).show();
                // removing updates
                // locationManager.removeUpdates(locationListener);
                // explicitly turning off GPS
                Intent intent = new Intent("android.location.GPS_ENABLED_CHANGE");
                intent.putExtra("enabled", false);
                sendBroadcast(intent);
                System.out.println("GPS disabled!");

                finalLatNow = myCurrentLat;
                finalLonNow = myCurrentLon;
                //
                // if(gotLoc == 0){
                if (myCurrentLon != null
                        && myCurrentLat != null && (firstLoc.getAccuracy() <= 10)) {
                    // locationManager.removeUpdates(locationListener);
                    gotLoc = 1;
                    Intent i = new Intent(StoreSelection.this, LastVisitDetails.class);

                    i.putExtra("currUsrLon", myCurrentLon); // 2nd
                    i.putExtra("currUsrLat", myCurrentLat); // 1st
                    i.putExtra("storeID", selStoreID);
                    i.putExtra("selStoreName", selStoreName);
                    i.putExtra("imei", uuid);
                    i.putExtra("date", userDate);


                    runOnUiThread(new Runnable() {
                        public void run() {
                            try {
                                // stuff here

                                pDialog2.dismiss();
                            } catch (Exception e) {
                                e.printStackTrace();
                            }
                        }
                    });
                    System.out.println("--Removing Loc. Updates--");
                    remUpdates();

                    syncTIMESTAMP = System.currentTimeMillis();
                    Date dateobj = new Date(syncTIMESTAMP);
                    SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
                    fullFileName1 = df.format(dateobj);

                    dbengine.open();
                    dbengine.UpdateStoreStartVisit(selStoreID, fullFileName1);
                    dbengine.close();

                    startActivity(i);
                    finish();

                } else {

                    if (myCurrentLon == null && myCurrentLat == null) {
                        // alert + GPS not locking on..do something()
                    } else {
                    }
                    /*if (!isOnline()) {
                        // alert + not online...do something()
                        showNoConnAlert();
                    } else {
                    }*/
                }
                //
                /*
                 * } else{}
                 */

            } else {
                System.out.println("INSIDE ELSE -- GOTLOC");

            }
        }

    };

    // locationManager.requestLocationUpdates(locationManager.getBestProvider(new
    // Criteria(), true), 2000, 4, locationListener);

    // enable gps everytime we request location update
    /*
     * Intent enableGPS = new Intent("android.location.GPS_ENABLED_CHANGE");
     * enableGPS.putExtra("enabled", true); sendBroadcast(enableGPS);
     */

    // ** ORIG Grequest location updates from GPS string

    /*
     * locationManager.requestLocationUpdates(locationManager.GPS_PROVIDER,
     * ONE_MIN, 4, locationListener);
     */

    // ** now remove updating of co-ordinates

    // locationManager.removeUpdates(locationListener);

    /*public Location getBestLoc(){

        if(firstLoc.getAccuracy() <= newLoc.getAccuracy() && newLoc.getAccuracy() <= 10) {

            return firstLoc;
        }
        else if(newLoc.getAccuracy() <= firstLoc.getAccuracy() && newLoc.getAccuracy() <= 10){

            return newLoc;
        }
        else {
            return newLoc;
        }

    }*/

    void getUserLoc() {
        if (gotLoc == 1  && (firstLoc.getAccuracy() <= 10)) {
            locationManager.removeUpdates(locationListener);
        } else {
        }

        final Criteria criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_FINE);
        criteria.setHorizontalAccuracy(Criteria.ACCURACY_FINE);
        // criteria.setVerticalAccuracy(Criteria.NO_REQUIREMENT);
        criteria.setAltitudeRequired(false);
        // criteria.setBearingAccuracy(Criteria.NO_REQUIREMENT);
        criteria.setBearingRequired(false);
        criteria.setCostAllowed(true);

        criteria.setPowerRequirement(Criteria.POWER_HIGH);

        runOnUiThread(new Runnable() {
            public void run() {
                try {
                    // stuff here
                    /*
                     * progressDialogGPS = ProgressDialog.show(_activity,
                     * null, null);
                     * progressDialogGPS.setContentView(R.layout.loader);
                     * progressDialogGPS
                     * .getWindow().setType(WindowManager.LayoutParams
                     * .TYPE_KEYGUARD_DIALOG);
                     */

                    /*locationManager
                            .requestLocationUpdates(locationManager
                                    .getBestProvider(criteria, true),
                                    TEN_SECS, 4, locationListener);*/

                    locationManager.requestLocationUpdates(locationManager.GPS_PROVIDER, 0l, 0.0f, locationListener);

                    // remove updates #
                    if (gotLoc == 1 && (firstLoc.getAccuracy() <= 10)) {
                        locationManager.removeUpdates(locationListener);
                    } else {
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });

        /*
         * try { Thread.currentThread().sleep(2000); } catch
         * (InterruptedException e) { // TODO Auto-generated catch block
         * e.printStackTrace(); }
         */

    }

    void remUpdates() {
        //if(firstLoc.getAccuracy() <= 10){
        locationManager.removeUpdates(locationListener);
        //}
        //else {}
    }
}

任何帮助都是可观的..

Answer 1

当使用 execute.get(1, TimeUnit.MINUTES) 时，它将异步任务转换为同步任务。在这种情况下使用异步任务是没有用的。您可以在启动 asynctask 时启动一个单独的线程来监视时间并在之后执行所需的操作。您可以创建一个实现可运行的类并将 asyctask 作为构造函数参数传递并在内部取消它。

class checkAyscTask implements Runnable {
    AsyncTask<Void, Void, Boolean> mAT;
    Context context;

    public checkAyscTask(AsyncTask<Void, Void, Boolean> at) {
        mAT = at;
    }

    @Override
    public void run() {
        mHandler.postDelayed(runnable, 60000);
        // After 60sec the task in run() of runnable will be done
    }

    Handler mHandler = new Handler();
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            if (mAT.getStatus() == Status.RUNNING || mAT.getStatus() == Status.PENDING) {
                mAT.cancel(true); //Cancel Async task or do the operation you want after 1 minute
            }
        }
    };
}

task_GetGPS = new GetGPShotfix(); 
task_GetGPS.execute();
checkAyscTask chk = new checkAyscTask(task_GetGPS);
// Thread keeping 1 minute time watch
(new Thread(chk)).start();