java - Android 错误

Question

你好，我在 android 中有一个类

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 = 5; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 30 * 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 est� activado el gps
                showSettingsAlert();
            } else {
                this.canGetLocation = true;
                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(){

        new AlertDialog.Builder(mContext)
        //.setIcon(android.R.drawable.ic_dialog_alert)
        .setTitle("Activar GPS")
        .setMessage("El GPS no esta habilitado. �Desea Activarlo?")
        .setPositiveButton("Si", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {

                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);    
            }

        })
        .setNegativeButton("No", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {

                //TO DO   
            }

        } )
        .show();

    }

    @Override
    public void onLocationChanged(Location location) {
        this.location = location;
    }

    @Override
    public void onProviderDisabled(String provider) {
        showSettingsAlert();
    }

    @Override
    public void onProviderEnabled(String provider) {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
        // Setting Dialog Title
        alertDialog.setTitle("Activar GPS");
        // Setting Dialog Message
        alertDialog.setMessage("El GPS esta habilitado.");
        // Showing Alert Message
       // alertDialog.show();
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }
    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}

它的工作并返回 GPS，但是当我在另一个类中调用时，我会发送 lopper.prepare 错误

java.lang.RuntimeException:无法在未调用 Looper.prepare() 的线程内创建处理程序

getLocation(GPSTracker.java:69)

(GPSTracker.java:47)

哪里出错了？

问候!

Answer 1

我认为解决方案很简单。为什么要延长服务。我见过很多 GPSTracker 的实现，我自己也用过一个，不需要扩展任何类。只要去掉“扩展服务”部分和所有来自扩展服务的方法就可以了。每当您需要位置数据时，请创建一个 GPSTracker 对象。

如果您想在跟踪器获取数据时收到通知，那么只需创建一个接口(interface)并在 Activity 中实现它即可。之后执行以下操作:

listener.onInterfaceMethod(location);