How to avoid repeating code in Android across classes?

Question

I need to retrieve user location in different screens of my application. I have written the code to get the location in one of screen activity, however, now I want to get the location in another screen activity too. Is there anything I can do to avoid writing the same code again?

        // variables
        // These variables will be repeated
        LocationProvider locationProvider;
        double latitude;
        double longitude;
        private String userPostcode;
        // ===============

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                      Bundle savedInstanceState) {

        // This code will be repeated
        locationProvider = new LocationProvider(getActivity());
        latitude = locationProvider.getLatitude();
        longitude = locationProvider.getLongitude();
        if (isNetworkAvailable(getContext())) {
            getPostcode();
        } else {
            Toast.makeText(getActivity(), "Internet or GPS is not available. To get the best location one or both of these must be on",
                    Toast.LENGTH_LONG).show();
        }
 // =============
        return inflater.inflate(R.layout.fragment_location, container, false);
    }




      // These two methods will be repeated
        private void getPostcode(){
                    Geocoder geoCoder = new Geocoder(getActivity().getApplicationContext(), Locale.getDefault());
                    List<Address> address = null;

                    if (geoCoder != null) {
                        try {
                            address = geoCoder.getFromLocation(latitude, longitude, 1);
                        } catch (IOException e1) {
                            e1.printStackTrace();
                        }
                        if (address.size() > 0) {
                            userPostcode = address.get(0).getPostalCode();
                        }
                    }
                }


            private boolean isNetworkAvailable(final Context context) {
                    final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
                    return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
                }
    // ====================

If its possible to avoid repeating please can someone show me/show me how it can be done please. I am new to android and might have missed something stupid.

Answer 1

Add the getPostcode() in a seperate class. You may modify it as followed.

public class Utils {


    public static String getPostcode(Context context, double lat, double lng){
        Geocoder geoCoder = new Geocoder(context, Locale.getDefault());
        List<Address> address = null;

        if (geoCoder != null) {
            try {
                address = geoCoder.getFromLocation(lat, lng, 1);
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            if (address.size() > 0) {
                return address.get(0).getPostalCode();
            }
        }
        return null;
    }


    public static boolean isNetworkAvailable(final Context context) {
        final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
        return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
    }
}

in your fragment/activity do this

if(Utils.isNetworkAvailable(this)) {
            String postCode = Utils.getPostcode(this, yourLat, yourLng);
        }

change this to getActivity() if in Fragment.

Answer 2

You can create a utility class that does all the location work you want. Pass the activity/context object as a constructor parameter to the utility class. Then use the class methods to get what you want. Look at the following code for the utility class:

public class LocationHelper {
    private double mLatitude;
    private double mLongitude;
    private Context mContext;
    private LocationProvider mLocationProvider;

    // Dont know if you need Activity or Context object.
    // Pass whatever as per requirement
    public LocationHelper(Context context) {
        this.mContext = context;
        initLocation();
    }

    // Set the latitude and longitude here.
    // You can get the latitude and longitude using
    // getter methods.
    private void initLocation() {
        mLocationProvider = new LocationProvider(mContext);
        mLatitude = mLocationProvider.getLatitude();
        mLongitude = mLocationProvider.getLongitude();
    }

    public double getLatitude() {
        return mLatitude;
    }

    public double getLongitude() {
        return mLongitude;
    }

    // Get the post code as a string. Empty if failed to get any.
    public String getPostcode(){
        String userPostcode = "";
        Geocoder geoCoder = new Geocoder(mContext, Locale.getDefault());
        List<Address> address = null;

        //It is a redundant check since it will always be true
        if (geoCoder != null) {
            try {
                address = geoCoder.getFromLocation(mLatitude, mLongitude, 1);
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            // Also make sure to put a null check to avoid NullPointerException
            if (address != null && address.size() > 0) {
                userPostcode = address.get(0).getPostalCode();
            }
        }
        return userPostcode;
    }

    //To check if device is offline/online.
    public boolean isNetworkAvailable() {
        final ConnectivityManager connectivityManager = ((ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE));
        return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
    }
}

Answer 3

Make new class file and put these below function in that class file

private String getPostcode(Activity activity, Double latitude, Double longitude) {
        String userPostcode = null;
        Geocoder geoCoder = new Geocoder(activity.getApplicationContext(), Locale.getDefault());
        List<Address> address = null;

        if (geoCoder != null) {
            try {
                address = geoCoder.getFromLocation(latitude, longitude, 1);
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            if (address.size() > 0) {
                userPostcode = address.get(0).getPostalCode();
            }
        }
        return userPostcode;
    }

    private static boolean isNetworkAvailable(final Context context) {
        final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
        return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
    }

To access these function create the object of that class and call these fucntion

Answer 4

Methods that just simply return some value, you need to reuse them often and are not tied to any object or state, you can make them static.

Create some kind of utility class. For example

public class Utils {

    public static boolean isNetworkAvailable(final Context context) {
        final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
        return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
    }

    public static String getPostCode(Activity activity) {
        ...
    }
}

Then you can reuse it anywhere you like.

boolean isNetworkAvailable = Utils.isNetworkAvailable(context);

Answer 5

Yes, refractor into a separate class. Or find a way to get the data from one activity to an other. (putExtra(), Singleton, DataBase, SharedPreferences, etc)