类型MainActivity没有外围实例是在范围访问

Question

我有这样的代码，这是我想GPS从 GPSTracker类纬度和经度，但错误显示

  gps=new GPSTracker(MainActivity.this); 
      gps.getLatitude(); 

没有封闭的情况下类型MainActivity是在范围访问

的完整代码 BootComplete.java

public class BootComplete extends BroadcastReceiver{ 

//private static final String PREFS_NAME = null; 
public static final String PREFS_NAME = "MyPrefs"; 
String storedSimSerial; 
String currentSimSerial; 
String email;  //email address input by user, generate email and sent to this address 
String mobileno; //mobile number input by user, generate SMS and send to this address 
String sms;   //generate sms to user 
public GPSTracker gps; 


@Override 
public void onReceive(final Context context, Intent intent) { 

    SharedPreferences prefs = context.getSharedPreferences(PREFS_NAME, 0); 
    storedSimSerial = prefs.getString("storedSimSerial", ""); 
    mobileno = prefs.getString("trustedNum", ""); 
    email = prefs.getString("Email", ""); 
    TelephonyManager tm = (TelephonyManager) context.getSystemService(Service.TELEPHONY_SERVICE); 
    currentSimSerial = tm.getSimSerialNumber(); 

    if(currentSimSerial != null){ 
     if(currentSimSerial.compareToIgnoreCase(storedSimSerial) == 0){ 

     }else{ 

      prefs = context.getApplicationContext().getSharedPreferences(PREFS_NAME, 0); 
      SharedPreferences.Editor editor = prefs.edit(); 

      gps=new GPSTracker(MainActivity.this); 
      gps.getLatitude(); 

      sms = "Alert!!!\nSim card changed.\nSim Serial Number:\n"+tm.getSimSerialNumber()+ 
        "\nNetwork : "+ tm.getNetworkOperatorName()+"\nLatitude:\n" + gps.getLatitude(); 

      editor.putBoolean("SimChangeMail", true); 
      editor.putString("subjectSimChange", "Your Sim card has changed."); 
      editor.putString("bodySimChange","Sim Serial Number is :\n"+tm.getSimSerialNumber()+"\n" + 
        "This Sim serial number is unique and used to identify the owner.\nNetwork Operator is : "+ 
        tm.getNetworkOperatorName()+ 
        "\nThanks for using Mobile Security Application"); 
      editor.putString("SimChangeSms", sms); 
      editor.commit(); 

      SmsManager sm = SmsManager.getDefault(); 
      String num = mobileno; 
      sm.sendTextMessage(num, null, sms, null, null); 
     } 
    }else{ 

    } 
} 
} 

GPSTracker.java

public class GPSTracker 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 = 10; // 10 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 GPSTracker(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) { 
        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(GPSTracker.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; 
    } 

} 

Answer 1

你只能使用MainActivity.this如果BootComplete里面MainActivity嵌套类。

为您GPSTracker只需要一个背景下，你可以做

gps = new GPSTracker(context); 

Answer 2

试试这个队友：

MainActivity mainAct = new MainActivity(); 

mainAct.YouClass = mainAct.new YourClass(); 

希望它能帮助。