A sample usage of a Support Preference Fragment from Machinarius

Support Preference Fragment

package edu.msstate.nsparc.mdes.fragments;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.ListPreference;
import android.preference.Preference;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.github.machinarius.preferencefragment.PreferenceFragment;

import edu.msstate.nsparc.mdes.R;
import edu.msstate.nsparc.mdes.constants.Default;
import edu.msstate.nsparc.mdes.constants.PrefKey;
import edu.msstate.nsparc.mdes.constants.ResultCode;
import edu.msstate.nsparc.mdes.constants.SearchMethod;
import edu.msstate.nsparc.mdes.persistance.ZipCode;
import edu.msstate.nsparc.mdes.rest.MobileClient;
import edu.msstate.nsparc.mdes.rest.MobileResponse;
import retrofit.RetrofitError;

public class SettingsFragment extends PreferenceFragment
    implements SharedPreferences.OnSharedPreferenceChangeListener {

    public interface SettingsCallbacks {
    }
    private SettingsCallbacks callbacks;

    public static SettingsFragment newInstance() {
        return new SettingsFragment();
    }
    public SettingsFragment() {}

    SharedPreferences preferences;
    private SharedPreferences.Editor editor;
    private ListPreference searchMethod;
    private EditTextPreference zipCode;
    private ListPreference searchDistance;
    private ListPreference sortBy;

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            callbacks = (SettingsCallbacks) activity;
            activity.setTitle(R.string.title_fragment_settings);
        }
        catch(ClassCastException e) {
            throw new ClassCastException(activity.toString() + " must implement required interfaces");
        }
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        // http://stackoverflow.com/a/9685690/1747491
        float scale = getResources().getDisplayMetrics().density;
        int dpAsPixels = (int) (getResources().getDimension(R.dimen.activity_horizontal_margin)* scale + 0.5f);
        view.setPadding(dpAsPixels, dpAsPixels, dpAsPixels, dpAsPixels);
    }

    @Override
    public void onResume() {
        super.onResume();

        setPreferenceScreen(null);
        addPreferencesFromResource(R.xml.settings);

        preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
        preferences.registerOnSharedPreferenceChangeListener(this);
        editor = preferences.edit();

        searchMethod = (ListPreference) findPreference(PrefKey.SEARCH_METHOD);
        zipCode = (EditTextPreference) findPreference(PrefKey.Location.ZIP_CODE);
        searchDistance = (ListPreference) findPreference(PrefKey.SEARCH_DISTANCE);
        sortBy = (ListPreference) findPreference(PrefKey.SORT_BY);

        // configure preference objects
        zipCode.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object newValue) {

                // if not five characters
                if(newValue.toString().length() != 5) {
                    // set to default and don't update with newValue
                    setDefaultZip();
                }
                else {
                    // verify
                    new VerifyZipTask(newValue.toString()).execute();
                }

                return false; // signifies that we are handling the update of the Preference ourselves
            }
        });

        // remove zipCode preference if user is using GPS
        if(searchMethod.getValue().equals(SearchMethod.GPS)) {
            getPreferenceScreen().removePreference(zipCode);
        }

        // configure summaries
        searchMethod.setSummary(searchMethod.getEntry());
        zipCode.setSummary(zipCode.getText());
        searchDistance.setSummary(searchDistance.getEntry());
        sortBy.setSummary(sortBy.getEntry());
    }

    @Override
    public void onDetach() {
        super.onDetach();
        callbacks = null;
    }

    /**
     * @see <a href="http://stackoverflow.com/a/531927/1747491">Set preference summary</a>
     */
    @Override
    public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
        if(key.equals(PrefKey.SEARCH_METHOD)) {
            searchMethod.setSummary(searchMethod.getEntry());

            // enable or disable zipCode based on selection
            if(searchMethod.getValue().equals(SearchMethod.ZIP_CODE))
                getPreferenceScreen().addPreference(zipCode);
            else
                getPreferenceScreen().removePreference(zipCode);
        }
        else if(key.equals(PrefKey.Location.ZIP_CODE)) {
            zipCode.setSummary(zipCode.getText());
        }
        else if(key.equals(PrefKey.SEARCH_DISTANCE)) {
            searchDistance.setSummary(searchDistance.getEntry());
        }
        else if(key.equals(PrefKey.SORT_BY)) {
            sortBy.setSummary(sortBy.getEntry());
        }
        else
            return;

        // if a preference changed, invalidate job search results
        prefs.edit().putLong(PrefKey.LastUpdated.JOBS, 0).commit();
    }

    private void setDefaultZip() {
        Toast.makeText(getActivity(), "Invalid zip code.  Using Jackson, MS.", Toast.LENGTH_SHORT).show();
        editor.putString(PrefKey.Location.ZIP_CODE, Default.ZIP_CODE);
        editor.putFloat(PrefKey.Location.ZIP_CODE_LAT, Default.LAT);
        editor.putFloat(PrefKey.Location.ZIP_CODE_LON, Default.LON);
        editor.commit();
        zipCode.setText(Default.ZIP_CODE);
        zipCode.setSummary(Default.ZIP_CODE);
    }

    private class VerifyZipTask extends AsyncTask<String, Void, Integer> {
        ProgressDialog progressDialog;
        String newValue;
        final VerifyZipTask task = this;
        ZipCode result;

        public VerifyZipTask(String newValue) {
            this.newValue = newValue;
        }

        @Override
        protected void onPreExecute() {
            progressDialog = ProgressDialog.show(getActivity(), "", "Verifying zip code", true, true, new DialogInterface.OnCancelListener() {
                @Override
                public void onCancel(DialogInterface dialog) {
                    // if canceled just use Jackson, MS
                    task.cancel(true);
                    setDefaultZip();
                }
            });
        }

        @Override
        protected Integer doInBackground(String... params) {
            try {
                MobileResponse<ZipCode> response = MobileClient.lookupZip(newValue);

                if(response.isSuccessYN()) {
                    result = response.getResults().get(0);
                    return ResultCode.SUCCESS;
                }
                else {
                    return ResultCode.FAILURE;
                }
            }
            catch(NullPointerException e) {
                Log.e(getTag(), e.getMessage(), e);
                return ResultCode.FAILURE;
            }
            catch(RetrofitError e) {
                Log.e(getTag(), e.getMessage(), e);
                return ResultCode.FAILURE;
            }
        }

        @Override
        protected void onPostExecute(Integer success) {
            if(success == ResultCode.SUCCESS) {
                // zip code validated
                editor.putString(PrefKey.Location.ZIP_CODE, newValue);
                editor.putFloat(PrefKey.Location.ZIP_CODE_LAT, result.getLatitude());
                editor.putFloat(PrefKey.Location.ZIP_CODE_LON, result.getLongitude());
                editor.commit();
                zipCode.setText(newValue);
                zipCode.setSummary(newValue);
            }
            else {
                setDefaultZip();
            }

            progressDialog.dismiss();
        }
    }
}