Question

我正在开发一个应用，我希望广播接收器在启用互联网时呼叫服务。执行此操作时，应用程序将关闭。任何人都可以给我一步一步的解决方案。我的代码如下：

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;
            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) {
    //latitude = location.getLatitude();
    //longitude = location.getLongitude();

}

@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;
}

}

broad.java

公共类广泛扩展BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    // TODO Auto-generated method stub

    String mAction = intent.getAction();
    String status = NetworkUtil.getConnectivityStatusString(context);

       Toast.makeText(context, status, Toast.LENGTH_LONG).show();

       Intent i = new Intent(context,GPSTracker.class);
       context.getApplicationContext().startService(i);

}

}

错误日志

 03-15 09:31:05.116: E/AndroidRuntime(1457): FATAL EXCEPTION: main
 03-15 09:31:05.116: E/AndroidRuntime(1457): java.lang.RuntimeException: Unable to instantiate service com.example.broadcast.GPSTracker: java.lang.InstantiationException: com.example.broadcast.GPSTracker
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:1929)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.app.ActivityThread.access$2500(ActivityThread.java:117)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:985)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.os.Handler.dispatchMessage(Handler.java:99)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.os.Looper.loop(Looper.java:123)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.app.ActivityThread.main(ActivityThread.java:3683)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at java.lang.reflect.Method.invokeNative(Native Method)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at java.lang.reflect.Method.invoke(Method.java:507)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at dalvik.system.NativeStart.main(Native Method)
 03-15 09:31:05.116: E/AndroidRuntime(1457): Caused by: java.lang.InstantiationException: com.example.broadcast.GPSTracker
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at java.lang.Class.newInstanceImpl(Native Method)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at java.lang.Class.newInstance(Class.java:1409)
 03-15 09:31:05.116: E/AndroidRuntime(1457):    at android.app.ActivityThread.handleCreateService(ActivityThread.java:1926)
  03-15 09:31:05.116: E/AndroidRuntime(1457):   ... 10 more

Answer 1

每个服务都有自己的上下文，只需使用它即可。您无需传递服务和活动的上下文。

请从构造函数中删除参数，

      public GPSTracker() {

       }

当广播接收器在android中调用服务时，应用程序崩溃

1 个答案: