android構造函數undefined

我是android新手。我得到這個錯誤：構造GpsData（btnReport）是未定義這條線：android構造函數undefined

gps = new GpsData(btnReport.this);

驗證碼：

public class btnReport extends AsyncTask<String, String, Void> { 
    // GPSTracker class 
    GpsData gps; 

    @Override 
    protected Void doInBackground(String... params) { 
     String artID = params[0]; 

     // create class object 
     gps = new GpsData(btnReport.this); 

      double latitude = gps.getLatitude(); 
      double longitude = gps.getLongitude(); 
      String mlat = String.valueOf(latitude); 
      String mlon = String.valueOf(longitude); 

      // \n is for new line     
      new PostData().execute(mlat, mlon, artID); 

     gps.stopUsingGPS(); 
     return null; 
    } 

}

我能做些什麼？

這裏是GpsData：這裏

public class GpsData extends Service implements LocationListener { 

    private final Context mContext; 

    // flag for GPS status 
    boolean isGPSEnabled = false; 

    // flag for network status 
    boolean isNetworkEnabled = false; 

    // flag for GPS status 
    boolean canGetLocation = false; 

    Location location; // location 
    double latitude; // latitude 
    double longitude; // longitude 

    // The minimum distance to change Updates in meters 
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1000; // 1000 meters 

    // The minimum time between updates in milliseconds 
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute 

    // Declaring a Location Manager 
    protected LocationManager locationManager; 

    public GpsData(Context context) { 
     this.mContext = context; 
     getLocation(); 
    } 

    public Location getLocation() { 
     try { 
      locationManager = (LocationManager) mContext 
        .getSystemService(LOCATION_SERVICE); 

      // getting GPS status 
      isGPSEnabled = locationManager 
        .isProviderEnabled(LocationManager.GPS_PROVIDER); 

      // getting network status 
      isNetworkEnabled = locationManager 
        .isProviderEnabled(LocationManager.NETWORK_PROVIDER); 

      if (!isGPSEnabled && !isNetworkEnabled) { 
       // no network provider is enabled 
      } else { 
       this.canGetLocation = true; 
       // First get location from Network Provider 
       if (!isNetworkEnabled) { //! hinzugefuegt 
        locationManager.requestLocationUpdates(
          LocationManager.NETWORK_PROVIDER, 
          MIN_TIME_BW_UPDATES, 
          MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 
        Log.d("Network", "Network"); 
        if (locationManager != null) { 
         location = locationManager 
           .getLastKnownLocation(LocationManager.NETWORK_PROVIDER); 
         if (location != null) { 
          latitude = location.getLatitude(); 
          longitude = location.getLongitude(); 
         } 
        } 
       } 
       // if GPS Enabled get lat/long using GPS Services 
       if (isGPSEnabled) { 
        if (location == null) { 
         locationManager.requestLocationUpdates(
           LocationManager.GPS_PROVIDER, 
           MIN_TIME_BW_UPDATES, 
           MIN_DISTANCE_CHANGE_FOR_UPDATES, this); 
         Log.d("GPS Enabled", "GPS Enabled"); 
         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; 
    } 

    /** 
    * Stop using GPS listener 
    * Calling this function will stop using GPS in your app 
    * */ 
    public void stopUsingGPS(){ 
     if(locationManager != null){ 
      locationManager.removeUpdates(GpsData.this); 
     } 
    } 

    /** 
    * Function to get latitude 
    * */ 
    public double getLatitude(){ 
     if(location != null){ 
      latitude = location.getLatitude(); 
     } 

     // return latitude 
     return latitude; 
    } 

    /** 
    * Function to get longitude 
    * */ 
    public double getLongitude(){ 
     if(location != null){ 
      longitude = location.getLongitude(); 
     } 

     // return longitude 
     return longitude; 
    } 

    /** 
    * Function to check GPS/wifi enabled 
    * @return boolean 
    * */ 
    public boolean canGetLocation() { 
     return this.canGetLocation; 
    } 

    /** 
    * Function to show settings alert dialog 
    * On pressing Settings button will lauch Settings Options 
    * */ 
    public void showSettingsAlert(){ 
     AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext); 

     // Setting Dialog Title 
     alertDialog.setTitle("GPS is settings"); 

     // Setting Dialog Message 
     alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?"); 

     // On pressing Settings button 
     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); 
      } 
     }); 

     // on pressing cancel button 
     alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog, int which) { 
      dialog.cancel(); 
      } 
     }); 

     // Showing Alert Message 
     alertDialog.show(); 
    } 

    @Override 
    public void onLocationChanged(Location location) { 
    } 

    @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; 
    } 

}

確定是通過我的應用程序的方式： StartActivity：

 Intent intent = new Intent(StartActivity.this, ReportActivity.class); 
     startActivity(intent);

ReportActivity：

public class ReportActivity extends Activity implements OnClickListener { 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.report); 
     Button b = (Button) findViewById(R.id.report_TJ_btn1); 
     b.setOnClickListener(this); 
     b = (Button) findViewById(R.id.report_TJ_btn2); 
     b.setOnClickListener(this); 
     b = (Button) findViewById(R.id.report_TJ_btn3); 
     b.setOnClickListener(this); 
    } 
    @Override 
    public void onClick(View v) { 
     if(v.getId()== R.id.report_TJ_btn1) { 
      startActivity(new Intent(this,btnReport.class)); 
     } 
     if(v.getId()== R.id.report_TJ_btn2) { 
      startActivity(new Intent(this,btnReport.class)); 
     } 
     if(v.getId() == R.id.report_TJ_btn3) { 
      startActivity(new Intent(this,btnReport.class)); 
     } 
    } 

}

來源

2012-11-21 sarahsdev

安置自己的GpsData類 –

代碼更新 – sarahsdev

使用您activityname.this（其中使用AsycTask）而不是你的btnReport.this。

public class btnReport extends AsyncTask<String, String, Void> { 
     // GPSTracker class 
     GpsData gps; 

     @Override 
     protected Void doInBackground(String... params) { 
      String artID = params[0]; 

      MainActivity.this.runOnUiThread(new Runnable() { 
       @Override 
       public void run() { 
        gps = new GpsData(MainActivity.this); 
        double latitude = gps.getLatitude(); 
        double longitude = gps.getLongitude(); 
        String mlat = String.valueOf(latitude); 
        String mlon = String.valueOf(longitude); 

        // \n is for new line 
        // new PostData().execute(mlat, mlon, artID); 

        gps.stopUsingGPS(); 
       } 
      }); 
      return null; 
     } 

    }

來源

2012-11-21 09:43:29 Talha

你怎麼能說那？ –

我只是認爲它應該採用當前的背景。 – Talha

除非他已經發布了GpsData類，否則你正在猜測。 –

需要將什麼樣的數據類型傳遞給'GpsData`的構造函數？

你傳遞的AsyncTask一個實例，如果你想要一個Context，而不是（這是非常普遍的情況下），你可以嘗試：

gps = new GpsData(Application.getContext());

來源

2012-11-21 09:46:31 ScouseChris

android構造函數undefined

回答

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