Editor

SettingsActivity.java

package com.google.samples.smartlock.sms_verify.ui;

import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceScreen;
import android.support.v7.app.ActionBar;
import android.preference.PreferenceFragment;
import android.view.MenuItem;

import com.google.samples.smartlock.sms_verify.AppSignatureHelper;
import com.google.samples.smartlock.sms_verify.R;

import java.util.ArrayList;

/**
 * A {@link PreferenceActivity} that presents a set of application settings. On
 * handset devices, settings are presented as a single list. On tablets,
 * settings are split by category, with category headers shown to the left of
 * the list of settings.
 * <p>
 * See <a href="http://developer.android.com/design/patterns/settings.html">
 * Android Design: Settings</a> for design guidelines and the <a
 * href="http://developer.android.com/guide/topics/ui/settings.html">Settings
 * API Guide</a> for more information on developing a Settings UI.
 */
public class SettingsActivity extends AppCompatPreferenceActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setupActionBar();
        getFragmentManager().beginTransaction().replace(android.R.id.content,
                new SettingsFragment()).commit();
    }

/**
     * Set up the {@link android.app.ActionBar}, if the API is available.
     */
    private void setupActionBar() {
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            // Show the Up button in the action bar.
            actionBar.setDisplayHomeAsUpEnabled(true);
        }
    }

@Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                return true;
        }

return super.onOptionsItemSelected(item);
    }

public static class SettingsFragment extends PreferenceFragment {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

addPreferencesFromResource(R.xml.pref_main);

PreferenceScreen screen = getPreferenceScreen();
            AppSignatureHelper signatureHelper = new AppSignatureHelper(getActivity());

ArrayList<String> appSignatures = signatureHelper.getAppSignatures();
            Preference pref = screen.findPreference("app_signature");
            if (!appSignatures.isEmpty() && pref != null) {
                pref.setSummary(appSignatures.get(0));
            }
        }

}
}