Java tutorial
/* * Infinity Browser 2014 Matt Blackman * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package blackman.matt.Settings; import android.annotation.TargetApi; import android.content.Context; import android.content.res.Configuration; import android.os.Build; import android.os.Bundle; import android.preference.ListPreference; import android.preference.Preference; import android.preference.PreferenceActivity; import android.preference.PreferenceCategory; import android.preference.PreferenceFragment; import android.preference.PreferenceManager; import android.view.MenuItem; import android.support.v4.app.NavUtils; import java.util.List; import blackman.matt.infinitebrowser.R; /** * 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 PreferenceActivity { /** * Determines whether to always show the simplified settings UI, where * settings are presented in a single list. When false, settings are shown * as a master/detail two-pane view on tablets. When true, a single pane is * shown on tablets. */ private static final boolean ALWAYS_SIMPLE_PREFS = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupActionBar(); } /** * Set up the {@link android.app.ActionBar}, if the API is available. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) 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) { // This ID represents the Home or Up button. In the case of this // activity, the Up button is shown. Use NavUtils to allow users // to navigate up one level in the application structure. For // more details, see the Navigation pattern on Android Design: // // http://developer.android.com/design/patterns/navigation.html#up-vs-back // // TODO: If Settings has multiple levels, Up should navigate up // that hierarchy. NavUtils.navigateUpFromSameTask(this); return true; } return super.onOptionsItemSelected(item); } @Override protected void onPostCreate(Bundle savedInstanceState) { super.onPostCreate(savedInstanceState); setupSimplePreferencesScreen(); } /** * Shows the simplified settings UI if the device configuration if the * device configuration dictates that a simplified, single-pane UI should be * shown. */ 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); // Add 'data and sync' preferences, and a corresponding header. PreferenceCategory fakeHeader = new PreferenceCategory(this); fakeHeader.setTitle(R.string.pref_header_data_sync); getPreferenceScreen().addPreference(fakeHeader); addPreferencesFromResource(R.xml.pref_data_sync); bindPreferenceSummaryToValue(findPreference("default_board")); bindPreferenceSummaryToValue(findPreference("sync_frequency")); } /** {@inheritDoc} */ @Override public boolean onIsMultiPane() { return isXLargeTablet(this) && !isSimplePreferences(this); } /** * Helper method to determine if the device has an extra-large screen. For * example, 10" tablets are extra-large. */ private static boolean isXLargeTablet(Context context) { return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE; } /** * Determines whether the simplified settings UI should be shown. This is * true if this is forced via {@link #ALWAYS_SIMPLE_PREFS}, or the device * doesn't have newer APIs like {@link PreferenceFragment}, or the device * doesn't have an extra-large screen. In these cases, a single-pane * "simplified" settings UI should be shown. */ private static boolean isSimplePreferences(Context context) { return Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB || !isXLargeTablet(context); } /** {@inheritDoc} */ @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB) public void onBuildHeaders(List<Header> target) { if (!isSimplePreferences(this)) { loadHeadersFromResource(R.xml.pref_headers, target); } } /** * A preference value change listener that updates the preference's summary * to reflect its new value. */ 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 { // For all other preferences, set the summary to the value's // simple string representation. preference.setSummary(stringValue); } return true; } }; /** * Binds a preference's summary to its value. More specifically, when the * preference's value is changed, its summary (line of text below the * preference title) is updated to reflect the value. The summary is also * immediately updated upon calling this method. The exact display format is * dependent on the type of preference. * * @see #sBindPreferenceSummaryToValueListener */ 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(), "")); } /** * This fragment shows general preferences only. It is used when the * activity is showing a two-pane settings UI. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) 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("default_board")); } } /** * This fragment shows data and sync preferences only. It is used when the * activity is showing a two-pane settings UI. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) public static class DataSyncPreferenceFragment extends PreferenceFragment { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); addPreferencesFromResource(R.xml.pref_data_sync); // 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("sync_frequency")); } } }