Question

我正在创建一个简单的位置应用程序，根据命令存储用户的位置。我正在尝试使用GPS提供商和网络提供商来建立用户的位置。

使用Asynctask实现该过程，其工作方式如下：

检查上次已知的GPS位置和网络位置。如果位置在可接受的参数范围内，则线程结束。
如果最后知道的位置不可接受，则需要更新GPS和网络。
一旦找到4个网络位置或找到3个GPS位置，线程就会完成。

等待位置修复时会显示一个对话框。

问题：GPS似乎正在更新，而网络却没有。我试过单独更新NETWORK_PROVIDER，等了一个多小时没有结果。我试过开启和关闭WIFI。

GetGPS类的代码：

public class GetGPS extends AsyncTask<String, Void, String> implements LocationListener {

    private ProgressDialog progDialog;
    public double[] DataArray = {0.0,0.0,0.0};
    private Integer NetworkCount = 0;
    private Integer GPSCount = 0;
    private LocationManager mlocManager;       
    private Context mContext;
    private Activity mActivity;
    final LocationListener locationListener = (LocationListener) this;
    private boolean HasCompleted = false;


    public GetGPS(Context context, Activity activity) {
        mContext = context;
        mActivity = activity;   
    } 


    @Override
    public void onPreExecute() {
        Log.v(getClass().getName(),"PreExecute");


        mlocManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);

        //Stop any current GPS updates
        mlocManager.removeUpdates((LocationListener) this);

        //Get current system time in millis
        long currentTime = System.currentTimeMillis();

        //Check last known GPS location and corresponding accuracy and time
        String GPSlocationProvider = LocationManager.GPS_PROVIDER;
        Location lastKnownGPSLocation = mlocManager.getLastKnownLocation(GPSlocationProvider);

        if (lastKnownGPSLocation != null) {
            long lastGPStime = lastKnownGPSLocation.getTime();
            long timeDifference = currentTime - lastGPStime;
            float lastGPSaccuracy = lastKnownGPSLocation.getAccuracy();
            Log.v(getClass().getName(),"Found last known GPS! GPS time diff:"+timeDifference+", Accuracy:"+lastGPSaccuracy);
            if ((lastGPSaccuracy < 50) && (timeDifference < 180000)) {
                Log.v(getClass().getName(),"Acceptable last known GPS location!");
                DataArray[0] = (double) lastKnownGPSLocation.getLatitude(); 
                DataArray[1] = (double) lastKnownGPSLocation.getLongitude(); 
                DataArray[2] = (double) lastKnownGPSLocation.getAccuracy();
                HasCompleted = true;
            }
            else {
                Log.v(getClass().getName(),"Last known location GPS too inaccurate!");
            }   
        }
        else {
            Log.v(getClass().getName(),"No previous GPS locations!");
        }

        //Check last known network location and corresponding accuracy and time
        String NetworklocationProvider = LocationManager.NETWORK_PROVIDER;
        Location lastKnownNetworkLocation = mlocManager.getLastKnownLocation(NetworklocationProvider);

        if (lastKnownNetworkLocation != null) {
            long lastNetworktime = lastKnownNetworkLocation.getTime();
            long timeDifference = currentTime - lastNetworktime;
            float lastNetworkaccuracy = lastKnownNetworkLocation.getAccuracy();
            Log.v(getClass().getName(),"Found last known Network location! Time diff:"+timeDifference+", Accuracy:"+lastNetworkaccuracy);
            if ((lastNetworkaccuracy < 50) && (timeDifference < 180000)) {
                Log.v(getClass().getName(),"Acceptable last known Network location!");
                DataArray[0] = (double) lastKnownNetworkLocation.getLatitude(); 
                DataArray[1] = (double) lastKnownNetworkLocation.getLongitude(); 
                DataArray[2] = (double) lastKnownNetworkLocation.getAccuracy();
                HasCompleted = true;
            }
            else {
                Log.v(getClass().getName(),"Last known Network location too inaccurate!");
            }                   
        }
        else {
            Log.v(getClass().getName(),"No previous Network locations!");
        }

        // Request both providers to update
         mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,(LocationListener) this);
        mlocManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,(LocationListener) this);


        //Display dialog box
        progDialog = new ProgressDialog(mActivity);
        progDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Stop", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Log.v(getClass().getName(),"ProgDialog cancelled");
                mlocManager.removeUpdates(locationListener);
                GetGPS.this.cancel(true);
            }
        });
        progDialog.setMessage("Acquiring location..");
        progDialog.setIndeterminate(true);
        progDialog.setCancelable(false);
        progDialog.show();
        Log.v(getClass().getName(),"Show progdialog");
    }


   @Override
     public String doInBackground(String... params) {
         while (HasCompleted == false) {
                         }
         Log.v(getClass().getName(),"doInBackground completed");
         return "Success";

     }
     @Override
     public void onPostExecute(String result) {
         Log.v(getClass().getName(),"onPostExecute");
         //Destroy Dialog box
         progDialog.dismiss();
         //TODO: Deal with data

     }
     public void onLocationChanged(Location location) {
        Log.v(getClass().getName(),"onLocationChanged, Provider:'"+location.getProvider()+"'");

            // Check if from Network
            if (location.getProvider().equals("network")){
                Log.v(getClass().getName(),"Network location Changed");
                NetworkCount = NetworkCount + 1;
                if (NetworkCount > 3) {
                    DataArray[0] = (double) location.getLatitude();
                     DataArray[1] = (double) location.getLongitude();
                     DataArray[2] = (double) location.getAccuracy();
                     Log.v(getClass().getName(),"Location stored from Network!");
                     Log.v("data array 0","" + DataArray[0]);
                     mlocManager.removeUpdates((LocationListener) this);
                     HasCompleted = true;
                }
                else {
                    Log.v(getClass().getName(),"Network location count:"+NetworkCount);
                }
            } 

            //Check if from GPS
            if (location.getProvider().equals("gps")){
                Log.v(getClass().getName(),"GPS location Changed");
                GPSCount = GPSCount + 1;
                if (GPSCount > 2) {
                     DataArray[0] = (double) location.getLatitude();
                     DataArray[1] = (double) location.getLongitude();
                     DataArray[2] = (double) location.getAccuracy();
                     Log.v(getClass().getName(),"Location stored from GPS!");
                     //Log.v("data array 0","" + DataArray[0]);
                     mlocManager.removeUpdates((LocationListener) this);
                     HasCompleted = true;
                }
                else {
                    Log.v(getClass().getName(),"GPS location count:"+GPSCount);
                }
            } 

     }

        @Override
        public void onProviderDisabled(String provider) {
            Log.v("OnProviderDisabled", "OnProviderDisabled:"+provider);
        }
        @Override
        public void onProviderEnabled(String provider) {
            Log.v("onProviderEnabled", "onProviderEnabled:"+provider);
        }
        @Override
        public void onStatusChanged(String provider, int status,
                Bundle extras) {
            Log.v("onStatusChanged", "onStatusChanged, provider:"+provider+", Status:"+status);

        }

    }

以下列方式调用GetGPS类：

Context mContext = getActivity().getApplicationContext();
Activity mActivity = getActivity();
GetGPS getgps = new GetGPS(mContext, mActivity);
getgps.execute();

关于我哪里出错的任何帮助？提前感谢您的帮助。

另外：是否有一种简单的方法来实现Asynctask的超时？即如果在设定的时间段后没有找到位置修复，则线程停止。

Answer 1

关于您的第一个问题，请检查您的手机是否启用了GPS和网络提供商：
enter image description here

我也不确定在AsyncTask中实现LocationListener是否正确，我试着阅读它并遇到this。尝试阅读并实施他提出的解决方案。（我要做的是创建一个独立的位置Singelton类，它将具有停止和启动等方法，并将从AsyncTask控制。）

在你的doInBackground方法中，我会改变While循环，只需将Thread.sleep（50）放入其中。以防止忙碌的等待。

关于你的第二个问题，这里最简单的方法是检查doInBackground的while循环中经过的时间并停止必要的线程。

没有从NETWORK_PROVIDER获取更新

1 个答案: