Java tutorial
/* * This file is part of Droidpile: a Mailpile client for Android. * * You should have recieved a copy of the LICENSE file along with Droidpile. * If not: see <https://github.com/maikelwever/droidpile/blob/master/LICENSE> */ package org.maikelwever.droidpile; import android.content.Context; import android.content.Intent; import android.content.res.Configuration; import android.media.Ringtone; import android.media.RingtoneManager; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.preference.ListPreference; import android.preference.Preference; import android.preference.PreferenceActivity; import android.preference.PreferenceFragment; import android.preference.PreferenceManager; import android.preference.RingtonePreference; import android.text.TextUtils; import android.view.MenuItem; import android.support.v4.app.NavUtils; import java.util.List; public class SettingsActivity extends PreferenceActivity { private static final boolean ALWAYS_SIMPLE_PREFS = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupActionBar(); } private void setupActionBar() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { // Show the Up button in the action bar. getActionBar().setDisplayHomeAsUpEnabled(true); } } @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == android.R.id.home) { NavUtils.navigateUpFromSameTask(this); return true; } return super.onOptionsItemSelected(item); } @Override protected void onPostCreate(Bundle savedInstanceState) { super.onPostCreate(savedInstanceState); setupSimplePreferencesScreen(); } @Override public void onBackPressed() { startActivity(new Intent(getApplicationContext(), MainActivity.class)); } private void setupSimplePreferencesScreen() { if (!isSimplePreferences(this)) { return; } // In the simplified UI, fragments are not used at all and we instead // use the older PreferenceActivity APIs. // Add 'general' preferences. addPreferencesFromResource(R.xml.pref_general); } @Override public boolean onIsMultiPane() { return isXLargeTablet(this) && !isSimplePreferences(this); } private static boolean isXLargeTablet(Context context) { return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE; } private static boolean isSimplePreferences(Context context) { return ALWAYS_SIMPLE_PREFS || Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB || !isXLargeTablet(context); } @Override public void onBuildHeaders(List<Header> target) { if (!isSimplePreferences(this)) { loadHeadersFromResource(R.xml.pref_headers, target); } } private static Preference.OnPreferenceChangeListener sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener() { @Override public boolean onPreferenceChange(Preference preference, Object value) { String stringValue = value.toString(); if (preference instanceof ListPreference) { // For list preferences, look up the correct display value in // the preference's 'entries' list. ListPreference listPreference = (ListPreference) preference; int index = listPreference.findIndexOfValue(stringValue); // Set the summary to reflect the new value. preference.setSummary(index >= 0 ? listPreference.getEntries()[index] : null); } else if (preference instanceof RingtonePreference) { // For ringtone preferences, look up the correct display value // using RingtoneManager. if (TextUtils.isEmpty(stringValue)) { // Empty values correspond to 'silent' (no ringtone). preference.setSummary(R.string.pref_ringtone_silent); } else { Ringtone ringtone = RingtoneManager.getRingtone(preference.getContext(), Uri.parse(stringValue)); if (ringtone == null) { // Clear the summary if there was a lookup error. preference.setSummary(null); } else { // Set the summary to reflect the new ringtone display // name. String name = ringtone.getTitle(preference.getContext()); preference.setSummary(name); } } } else { // For all other preferences, set the summary to the value's // simple string representation. preference.setSummary(stringValue); } return true; } }; private static void bindPreferenceSummaryToValue(Preference preference) { // Set the listener to watch for value changes. preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener); // Trigger the listener immediately with the preference's // current value. sBindPreferenceSummaryToValueListener.onPreferenceChange(preference, PreferenceManager .getDefaultSharedPreferences(preference.getContext()).getString(preference.getKey(), "")); } public static class GeneralPreferenceFragment extends PreferenceFragment { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); addPreferencesFromResource(R.xml.pref_general); // Bind the summaries of EditText/List/Dialog/Ringtone preferences // to their values. When their values change, their summaries are // updated to reflect the new value, per the Android Design // guidelines. bindPreferenceSummaryToValue(findPreference("example_text")); bindPreferenceSummaryToValue(findPreference("example_list")); } } }